Semiconductor laser amplifier (SLA) based technology is an enabling technology for advanced optical networks. The potential for large-scale integration of SLA technology offers economical, high-performance devices that combine monolithic and hybrid solutions. Using SLAs, various devices can be built with enhanced functionalities as required for future optical networks. In a SLA, amplification of incident optical radiation takes place in the active layer along the length of an amplifier. However, frequency response of input signal (which can be amplified by a SLA), depends upon the available bandwidth. In this paper, a new analytical technique is outlined for bandwidth measurement of a SLA. This technique is based on measurement of saturation power and input power coupled in the active layer of SLA and is successfully applied to calculate the bandwidth of FP and near traveling wave (NTW) SLAs.

In this paper, we introduce a plane-wave-based transfer-matrix method (TMM) in application to photonic crystal (PC) functional elements and integrated circuits. In this formulation, the electromagnetic fields are expanded into superposition of plane waves associated with the crystal lattice, which facilitates access to many advanced Fourier analysis techniques. In addition to the standard solution of transmission, reflection and absorption spectra for a finite PC slab and photonic band structures for an infinite PC, the TMM can be used to handle wave propagation in semi-infinite photonic crystals and related waveguide structures. This capability is particularly useful for accurate solution of the intrinsic optical properties of a variety of functional elements comprising a PC integrated circuit. The TMM possesses a great advantage over the popular finite-different time-domain approach in handling these structures that are embedded in an environment of periodic geometries. We have discussed several prominent examples to demonstrate the power and capability of the TMM in this new frontier of applications. These include 2D PC filters based on resonant waveguide-cavity coupling, analysis of 2D channel add-drop filters that exhibit wideband continuous tunability, and discussion of the performance feature and radiation loss in resonant waveguide-cavity coupling based filters which are built on 2D slab PC platforms.

Position Sensitive Detector (PSD) is a position sensor utilizing the lateral photoelectric effect produced by the non-uniform illumination of a rectifying semiconductor junction. Recently, mostly researches of PSD focus on the linear requirements or response characters of PSD with p-n junction. However, this paper concentrates on a novel characteristics of PSD based on the Schottky junction. This junction has many distinguished traits comparing with the p-n junction. Since the intrinsic excellent characteristics, the Schottky PSD has faster response and higher sensitivity to the incident radiation, lager current density, low current leakage and so on. This paper provides an analysis and model of the Schottky-barrier PSD lateral potential creation, response characteristic and position linearity condition with the Schottky junction, which is deduced by the charge conversation law and the model of carriers transport. All the study work is the theoretical basis for design of this junction with better performance.

The general format of multifrequency acousto-optic coupled wave equation including normal and abnormal acousto-optic interaction is presented in this paper. The solutions of the equations for two independent ultrasonic wave signals in the Bragg limit are put forward. These include diffraction efficiency, compression, cross modulation and additional intermodulation intensities. Especially the differences between the abnormal and normal diffraction are pointed out and analysed. The experimental results are in good agreement with theoretical analyses.

We present in this paper a method to recover the refractive index profile of graded index waveguide from the effective indices by cubic spline interpolation function. It is proved by numerical analysis of several typical index distributions that the refractive index profile can be reconstructed closely to its exact profile with the presented interpolation model. This method can reliably retrieve index profile of both more-mode (more than 4 guiding mode) and fewer-mode (2-4) waveguides.

Making use of the information redundancy introduced by the cyclic prefix (CP), a new deterministic subspace algorithm for blind channel estimation in OFDM systems is proposed. Considered that only few received signals are used to estimate channel, the algorithm is appealing for transmissions over slowly varying channels. The performances of the proposed algorithm are demonstrated by simulation results

Overlapping-image multimode interference couplers with two-dimensional confinement, a new class of devices, permit uniform and nonuniform two-dimensional power splitting. Based on self-imaging effect, positions, intensities and phases of the overlapping-images are analyzed. The overlapping-imaging properties in multimode interference couplers with two-dimensional confinement are also concluded. And the guided-mode propagation analysis method is used to confirm the analytical results.

In this paper, we present a comparison analysis between directional couplers (DC) and multi-mode interferometers (MMI) based on high-index contrast ridge waveguides. It is found that the two devices are intimately related as the MMI is structurally derived from the DC. For the first time, the continuous evolution from the two-mode coupling characteristic of DC to the two-mode interference and multi-mode interference of MMI is demonstrated. The resulting MMIs are compared with the DC in terms of coupling length, polarization dependence, excess loss, and fabrication tolerances. We show that practical directional couplers with reasonable gap size can also be quite compact and have the same coupling length for both TE and TM polarizations. Consequently, the DC can be just as polarization insensitive as the MMI. These features, however, require careful design control involving a large set of design parameters. By comparison, the MMI design is more robust and involves fewer design variables.

A theoretical and experimental study of the semicircular waveguide dependence of Tl⁺-Na⁺ ion-exchange waveguide on exchange-time and line breadth is reported. Modeling, which includes the effect of ion-exchange time t and line breadth W, agrees well with our experiments showing that a semicircular waveguide depends on the longer exchange time and the narrower line breadth. The result may be used in arrayed microlens and integrated optical circuits, such as diffractive waveguide gratings, and so on.

We discuss the two-stage approximation of coupled-mode equations and apply it to all-fiber acousto-optic modulator. We take advantage of the perturbed coupled-mode equations to discuss the form of coupled-mode equations for optical fiber when the term of two-stage approximation has been reserved. Then we discuss the two-stage approximation of all-fiber acousto-optic modulator.

The ability to create multiple-wavelength chip with high spatial bandgap selectively across a III-V semiconductor wafer for monolithic photonic integration using a simple postgrowth bandgap engineering process such as quantum well intermixing (QWI) is highly advantageous and desired. Preferably, this process should not result in drastic change in both optical and electrical properties of the processed material. In addition, the process should also give high reproducibility to both lattice-matched and strained quantum well (QW) structures. In this paper, we report a new method that meets most of these requirements. This process is performed by first implanting the InGaAs/InGaAsP laser structures using phosphorous ion at 300 keV prior to QWI, the samples were pre-annealed at 600°C for 20 min. Subsequently the annealing temperature was ramped to 700°C and stayed constant for 120s for QWI. Blue bandgap shift of over 140 nm, relative to the as grown and control samples, has been obtained from the strained InGaAs-InGaAsP laser structure. Using this process, devices such as bandgap tuned lasers, multiple-section device such as integrated optically amplified photodetector have been demonstrated.

Transmissive and reflective optical touch switch architectures based on the use of light scattering are proposed. Key features include high ON/OFF switching ratio, tunable sensitivity, ease of implementation, and no leakage optical beam incident on the user. Experimental proof of concept using a visible laser diode and a plastic Dove prism arranged in the transmissive configuration shows a high 24.4 dB contrast ratio which is a hundred times higher than obtained in the previous total internal reflection-based optical touch switch. In addition, switching response in milliseconds is also investigated for both lifting and sliding the fingertip out of the touching surface of the optical touch switch. Our light scattering-based optical touch switch also supports multiple keystroke operation.

A set of coupled wave equations of multi-channel all-fiber acousto-optic modulation is deduced. The solutions of equations are obtained. The novel 2-channel surface acoustic wave (SAW) all-fiber acousto-optic modulator is presented and developed. Experimental results show modulator performance agrees with theoretical analyses.

We present recent advances in the development of a waveguide microspectrometer chip with high spectral resolution in the near-infrared part of the spectrum. The microspectrometer is designed for a high index contrast silicon-on-insulator (SOI) platform, where high number of spectral channels can be obtained with high spectral resolution in a compact device. We present a 100-channel SOI microspectrometer with designed spectral resolution of ~0.08 nm at 1.5 μm wavelength and about 8x8 mm² in size. A number of critical design issues are discussed, including design of deep-etched tapers near the Rowland circle required for high-resolution performance as well as coupling between closely spaced waveguides. Device fabrication process is discussed in detail, including two-step e-beam patterning and two-level ICP etches, the focus being on achieving deep and smooth vertical etches in silicon with controllable sub-micron waveguide widths and gaps. The potentially available spectral range of the microspectrometer is limited by the transparency of silicon, extending from the band edge of Si at 1.107 μm to the onset of lattice phonon absorption band near 5 μm. Such compact high-resolution multi-channel integrated microspectrometers are promising for a variety of applications, including spectroscopy, telecommunications, optical interconnects, environmental and bio-sensing.

622Mbits/s free space laser communication system is developed. IT's communication rate is 622Mbits/s. The whole system include three parts which are signal in and out circuit, laser driver and receive circuit and optical antenna. The communication principle is introduced. The experiment result shows that the transmission of data and image are satisfied with demands of design. It have a definite market value.

In order to get electroluminescent devices incorporate high efficiency, easy fabrication and long-term physical stability, single layer electroluminescent devices based on soluble p-type polymer PDDOPV [poly (2,5-bis (dodecyloxy)-phenylenevinylene)] doped by n-type soluble polymer PPQ [poly (phenyl quinoxaline)] are successfully fabricated. Compared with single layer device of pure PDDOPV, the turn-on voltage of doped single layer devices is drop from 4.5V to 2.6V, at the same applied voltage, the current is higher but still at the same order of magnitude, the brightness and luminescent efficiency are both enhanced more than one order of magnitude. At 10 V, the current, brightness and luminescent efficiency of devices of blends are 1.95, 30.9 and 16 times of those of devices of pure PDDOPV respectively. The remarkable enhancement of doped devices is attributed to the reduction of injection barrier of minority carrier and enhancement of minority carrier injection caused by the doping PPQ in PDDOPV. This result demonstrates that it is an effective way to improve the device performance by doping n-type polymer in p-type polymer.

We demonstrate a self-seeded gain-switched Fabry-Perot laser diode (FP-LD) for simultaneous generation of stable picosecond pulses at five close wavelengths. The principle of the laser is based on filtering the spectrum of one of the FP-LD modes with a tunable spectrum-split fiber Bragg grating (FBG). In addition to two wavelengths produced from the reflection end of the FBG, three more wavelengths can emerge from the transmission end of the FBG when the laser is adjusted properly. The pulse characteristics can be adjusted by controlling the gain-switching frequency and the temperature of the FP-LD and the separation of the reflection peaks of the FBG. The tradeoffs in balancing pulse intensities, optimizing side-mode-suppression ratios, and equalizing wavelength separations are studied. We also demonstrate the scalability of the laser by cascading another FBG to select a different mode of the FP-LD, which defines another set of five wavelengths. To switch from one set of wavelengths to the other, we only need to adjust the gain-switching frequency and the temperature of the FP-LD. This laser is perhaps the most cost-effective one demonstrated so far for the generation of multiwavelength picosecond pulses with close wavelength separations.

Optical switch is a kind of very important passive device, since it gets extensive application in more and more fields, therefore also gets the universal solicitude of people. the index of optical switch, conversion time is the key that affects entire optical network performance, so seeking to the optical switch of more rapid response tine is the program that people are now studying with great efforts. The optical switch is the device according to requiring that convert optical signal of a optical channel into another optical channel, and the time since one optical signal of one channel declines to the optical signal risings in another channel is defined as conversion time of the optical switch .This paper has discussed the property parameter of optical switch. And the test method of the conversion time of optical switch, have given the relation result of test installation. Besides, we have given out a kind of working principle of the whole optical logic switch of optical cable and relation installation. And have analyzed its characteristic.

A novel polymer-based switch array using a vertical waveguide structure is introduced to meet the ongoing requirements of smaller and higher integrated optical circuits. The 1×3 and 2×3 electro-optic (EO) switch arrays with the vertical waveguide structure configuration are numerically simulated based on the beam propagation method (BPM). The influences of different parameters including the length of coupler, the distance between the contiguous lower channels, the distance between the contiguous upper channels and the angle of the upper channel on the performance of the switch array are also discussed. The simulation results show that the present configuration can provide better performance on the 2×3 EO switch array.

This paper discusses that we apply the projection technique of DLP to the target generator of optics. So we carry out the imaging creation automatically. And we will apply this technique to the modern test of optics system parameter. If CCD is receiver, it can achieve auto-measuring. Thus, this testing system is more objective, exacter, better measuring efficiency, and it can replace the traditional measuring method by eyes gradually.

Highly oriented ferroelectric strontium barium niobate (Sr_0.6Ba_0.4Nb₂O₆) thin films were prepared on P-type Si(100) substrate by the Sol-Gel process. The XRD patterns of the SBN films show that SBN film prepared by using NbCl5, KOH as raw materials performed a highly c-axis preferred orientation perpendicular to the Si substrate, better than films that was prepared using Nb(OC₂H₅)₅ as starting agents. It may be duo to the existence of the potassium ion that not be filtered out completely during the preparation of the niobium alkoxide. The characteristics of D-F and C-V curves were obtained for SBN/Si film. The film exhibits high dielectric constant. In order to investigate ferroelectric characteristics further, the P-E loops of the SBN/Pt/Si were also measured. The films show better optical properties, transmittance of Sr_0.6Ba_0.4Nb₂O₆ films on MgO(001) and SiO₂ substrates was more than 60% at the range from 450 to 850nm, refractive index was measured to be 2.14 and 2.12 on the MgO and SiO₂ substrate at 633nm respectively.

Dense and crack-free SBN thin films with the preferred c-axis orientation were successfully fabricated by the sol-gel method on Si(100) substrates with a MgO buffer layer. It was found that introducing the MgO buffer layer could effectively promote the formation of TTB SBN phase from SN and BN phases at lower temperature. Effects of annealing temperature and thickness of MgO buffer layer on the structural and morphological properties of SBN thin films were investigated. The SBN film with MgO buffer layer showed excellent epitaxy and densely packed grain morphology. The capacitance-voltage (C-V) properties of SBN films deposited on silicon substrates were found completely different from those of the films deposited on MgO-buffered silicon substrates, the C-V curves of SBN/Si films and SBN/MgO/Si films represent typical shapes of asymmetric and butterfly, respectively, indicating the improvement of the electrical properties and ferroelectric properties of the SBN films by introducing the MgO buffer layer.

We present an array of electro-optic Bragg gratings for on-chip optical waveguide interconnect applications. These electro-optical gratings can serve as switchable couplers to couple high-speed optical signals from a vertical cavity surface emitting lasers (VCSEL) to on-chip polymeric waveguides and from waveguides to photodetectors. The unique switching feature provides a promising solution to facilitate dynamically reconfigurable on-chip optical interconnects architecture for intra-chip, chip-to-chip and board-to-board data communications. We demonstrate on-chip switched optical waveguide interconnect using electro-optic grating and polymeric channel waveguides on a silicon substrate.

Long period fiber gratings (LPGs) have been fabricated in photosensitive fiber by use of point to point exposure method. The fiber is mounted on a constantly moving stage with a highly precise positioning function while a frequency-doubled Argon ion laser (244 nm) is switched on/off by an acousto-optic modulator (AOM). The development of transmission spectrum (HE1,5) and resonant wavelength of the LPGs as a function of laser exposure time is obtained. We present a thermal processing technique to stabilize the LPGs characteristics. The influence of hydrogen diffusion and temperature factor on the resonance wavelength and transmission peak loss is analyzed detailedly.

The planar waveguide optical couplers are of prime importance in optical communication and optical signal processing system. Comparing with the optical fiber coupler (OFC) which fabricated by fused biconical taper technology, the planar waveguide couplers are more compact size, lower loss, better uniformity, easier manufacture and integration. Multimode interference (MMI) couplers have many advantages, such as compact size, wavelength and polarization insensitivity, fabrication tolerances and low loss, etc., which concentrate more and more attention. Conventional MMI devices are based on the uniform index waveguides. When the number of input/output waveguides becomes larger, the intrinsic propagation constant error, which will cause bad uniformity of output power, can’t be neglected. In fact, most waveguide devices are graded-index. With the enhanced compatibility of MMI coupler, the performance can be improved at the same time. Prior study shows that graded-index MMI couplers reach the best performance under certain index contrast. Among many available materials, glass is chosen to be the substrate of the coupler, because of its good features, such as low loss, ease fabrication, cheap cost, and so on. In this paper, an 8×8 MMI optical coupler is designed based on the principle of graded-index MMI. The coupler is composed of a waveguide, which is designed to support a large number of modes, and several access (usually single-mode) waveguides, which are used to launch light into and recover light from that multimode waveguide. The total length of the device is less than 3.5 centimeter, including S-bends which lead the multiple images to the output of the device with the spacing D=250μm to make the device fiber compatible. In this paper, we describe an experimental realization of the 8×8 graded-index MMI optical coupler and the measurement of its performance with the testing laser of the wavelength of 1.55μm. The device is fabricated by ion-exchange on BK7 glass substrate. During the ion-exchange process, a melting mixture of AgNO₃ : (KNO₃ : NaNO₃) (molar ratio, 0.001:1) is used at 350~380°C for different times (range from 8 to 18 hours) to fabricate the coupler. The experimental results show that the performance of the optical coupler is quite promising. For instance, while launching light from No.5 waveguide, the uniformity of the device is approximately 0.72dB. Optimization of design and fabrication is going on to improve the total performance of the optical coupler.

We report the demonstration of a fiber optic device integrated with the functions of both an electro-optic modulator and a polarizer. The device was made from thermal poling of a side-polished commercial PANDA fiber. The part of the electrode on the polished flat was of a micro-strip shape measured 60μm wide and 60mm long. The special electrode was not only as a wire to conduct electric voltage, but also as a metal waveguide to create surface plasma wave. The sample fiber was poled thermally at temperature of 260°C by applying a DC voltage of 3kV across the electrodes for 15 minutes. The device has demonstrated a polarization extinction ratio of 32 dB and an electro-optic coefficient of 0.15pm/V for the TE mode. The theoretical analysis of the poled fiber waveguide was done and its results fit in with the experiments well. The device may be used as a polarization-maintaining fiber optic phase modulator, a fiber polarizer, or both at the same time. The device can also be used as a component to construct polarization stable all fiber devices such as intensity modulators and sensors.

The paper discusses a modern method to test the out pupil diameter and out pupil distance of the optical system. It is based on DLP technique of optoelectric graph generating automatically, CCD imaging technique and l image processing technique of computer. This method takes advantages of fast testing, high precision, high automatization and numeralization.

In the system of size measurement by laser scanning, the laser intensity is necessarily kept stability. But in practice, output intensity of laser is continuously attenuated as time passed, so that precision accuracy of detecting system becomes poor. The paper analyzes the effect of laser intensity changing on accuracy of size measurement by laser scanning, provides with the auto-measured circuit and the measuring methods of the output laser intensity, and the method of electrical compensation for intensity change. The method has been applied to the instrument of diameter measurement by laser scanning on line successfully, which is effective and feasible.

A new, compact laser Doppler velocimetry is proposed, which is composed of a single-mode vertical-cavity surface-emitting laser modulated by a dynamical triangular current and a collimating lens. It can indicate the direction of velocity without ambiguity in the wide dynamic range of 5.2mm/s to 479.9mm/s when the sampling time is 0.1 second in the measurement. The accuracy of velocity measurement is better than 3.1% in the whole velocity range. What's more, this LDV works very well on different diffusing surfaces, even on a black glossy photographic paper.

Erbium-doped fiber (EDF) lasers with active coupling cavities have recently shown to enable the production of multiwavelength oscillations with various novel functions. This paper reviews the advances of such lasers. The lasers may be designed to produce multiwavelength oscillations in both C and L bands, either as a combined band or as two separate bands. In the C band, the laser can operate in a multiwavelength regime with controllable output powers and tunable wavelengths for any one individual lasing line. Wavelength-switching is also possible; switching responses of about 100 Hz are typical. In the L band, the laser exhibits multiwavelength bistable phenomena. The bistable hysterisis behaviors for a dual-wavelength laser evolve in antiphase with respect to each other. The width of the bistable region can be controlled; it could be designed to be as wide as a few hundred milliwatts. The two wavelengths can be switched from one to the other, with typical switching times of 4 to 15 ms. By suitably controlling the bistability, simultaneous multiwavelength oscillations in the L band alone, or in combination with the C band, can be obtained. A new wavelength-tuning and switching mechanism can be achieved by using such bistabilities. With this scheme, widely tunable and switchable lasers in fiber ring and linear configurations have been constructed with two commercially available tunable ordinary fiber Bragg gratings (FBGs). The lasers can be tuned over the whole L-band although the tunable range of each of the FBGs is only about 15 nm.

We will describe recent results in all-optical packet switching with all-optical header processing using Fabry-Perot laser diodes (FP-LD). First, we will report an all-optical header processor and control signal generator using a single FP-LD with a special two-intensity-level control signal and a novel self-routing address format for the data packets. We then show that the special control signal can be generated by direct modulation of a DFB laser with square electrical pulses thus simplifying implementation. We will demonstrate that a single Fabry-Perot laser diode can also serve as an all-optical on/off switch with all-optical header processing. The header rate is 5 Gb/s and the payload rate is 10 Gb/s. The all-optical on/off switch can also be realized by using a FP-LD as the header processor only and executing the packet switching at a separate stage. The two-stage implementation of all-optical on/off switch eliminates the residue header bits problems if only a single FP-LD is used. Finally, we propose an all-optical packet-switched ring network which can be constructed from the all-optical on/off switches demonstrated.

An efficient and tunable Er³⁺/Yb³⁺ co-doped cladding pumped fiber ring laser operating in L-band is demonstrated. Rejecting the amplified spontaneous emission (ASE) of C-band by a fiber Bragg grating (FBG) into the same Er³⁺/Yb³⁺ co-doped fiber, the laser can operate in L-band stably. The insertion of the FBG can reduce the lasing threshold, and narrow the 3dB line-width of output laser. Using a two-section high-birefringence fiber loop mirror as a wavelength filter, the output wavelength can be tuned over 40nm range. The lasing threshold is about 48.80mW and the side mode suppression ratio is better than 51dB.

A tunable Er³⁺/Yb³⁺ co-doped cladding-pumped all fiber ring laser is presented. Under the maximum pump power of 3594.5mW, the absorbed pump power of the fiber is measured to be 2737.37mW, the maximum output power of the fiber laser is 438mW, and the slope efficiency is greater than 15.9%. By using a fiber Bragg grating (FBG) as a wavelength filter, the linewidth of output laser is as narrow as 0.04nm by 3 dB, and by compressing or stretching the FBG, tuning range of 4.0nm is realized, the side mode suppression ratio is about 42dB. We also study the relationship between the output power and the splitting ratio of the output coupler, and it is found that there is an optimum splitting ratio of the output coupler at which the highest output power can achieve 647mW.

High efficient coupling between waveguide amplifier and single mode fiber is an important aspect for component integration in the optical communication. Mode matching degree between waveguide and fiber straightly affects coupling loss and actual light intensity distribution in waveguide. In this paper, Bessel function field in step refractive index fiber excites erbium-doped Al₂O₃ rib waveguide amplifiers on silicon substrate with SiO₂ buffers with large refractive index changes. Rib height is selected 0.8μm for 1μm film thickness and 3μm rib width waveguide amplifier for single mode operation at signal wavelength. Signal and pump guided modes are calculated by finite element method. Mode excitation fractions of signal and pump are obtained. The dependences of coupling loss and subsequent gain on fiber core radius and fiber-waveguide offset are analyzed in detail. The coupling losses between fiber and three different geometry structure waveguide amplifiers (rectangle, trapeze, trapeze upside down) with the same active core cross-section area are compared. The gains of corresponding waveguide amplifiers are compared as well as.

Recent developments of Bismuth-based erbium-doped fibers (Bi-EDFs) have demonstrated their potential applications for broadband amplifiers, particularly for the L-band in DWDM systems, for short pulse amplifiers to be used in very high bit-rate transmission systems (up to 160 Gbps), and for ultra wideband tunable fiber ring lasers. The low concentration quenching of erbium ions in Bi-based glass permits efficient high erbium concentration Bi-EDFs (up to 26,000 ppm) to be fabricated allowing the realization of ultra-short length erbium-doped fibre amplifiers and fiber lasers. In this paper, we reported the performance of two Bi-EDFs with different erbium ions concentrations for signal amplification. One fiber was doped with 6,470 wt-ppm of erbium ions and the other was doped with 3,250 wt-ppm of erbium ions. The performance of a 253-cm long Lanthanum co-doped Bi-based EDF (3,250 ppm of erbium) for the amplification of 142 wavelength channels was evaluated. 140 of the input signals were located at the 50-GHz ITU grid. Signal gains of over 20 dB and NF less than 6.7 dB were measured for all the channels with wavelengths ranging from 1554.13 nm to 1612.22 nm (i.e. over 58 nm). 3-dB bandwidth of 53.9 nm and quantum conversion efficiency of about 60 % were attained when the fiber was pumped with 350 mW and 623 mW of pump power, respectively. The performance of an ultra-short length Bi-EDFA, using 23-cm of Bi-EDF doped with 6,500 ppm of erbium ions pumped at 980 nm, for the amplification of picosecond pulses will be discussed. The results of an ultra wideband (106 nm) tunable fiber ring laser based on the higher erbium concentration Bi-EDF will also be presented.

A wideband double-pass discrete Raman amplifier with high gain efficiency and improved gain polarization dependence is reported. In this Raman amplifier, by using a one-end gilded fiber as the broadband reflector, both signals and pumps are reflected to propagate through the gain fiber in the opposite direction of the input. An increase in net gain and an improved polarization dependence of Raman gain have been achieved compared with that in a typical co-pumped Raman amplifier. The advantages of this proposed new configuration have been studied experimentally.

Theoretic characteristics of Er³⁺-Yb³⁺ co-doped phosphate glass waveguide amplifier are studied by resolving rate-propagation equations with overlapping integral method. Considering the effect of the up-conversion and ASE, the amplifier gain and ASE spectrum are obtained. The relations between the amplifier gain and several parameters are analyzed, such as the waveguide length, pump power, up-conversion coefficient, propagation loss and so on. The experiment result agrees well with the numerical result.

A novel technique to introduce tunable linear chirp to a uniform fiber Bragg grating (FBG) without shift of central Bragg wavelength based on a magnetic field applied to a magnetostrictive rod capable of tuning polarization mode dispersion (PMD) is proposed. This all-fiber PMD compensation technique is cost-effective and flexible in designing the differential group delay (DGD). Based on the numerical simulations, a 10 Gb/s NRZ transmission system is compensated by this grating. The result demonstrates a significant improvement can be achieved in the eye pattern of the received signal.

In order to find the optimal design for a given specification of an optical communication link, an integrated simulation of electronic, optoelectronic, and optical components of a complete system is required. It is very important to be able to simulate at both system level and detailed model level. This kind of model is feasible due to the high potential of Verilog-AMS language. In this paper, we propose an effective top-down design methodology and employ it in the development of a complete VCSEL-based optical links simulation. The principle of top-down methodology is that the development would proceed from the system to device level. To design a hierarchical model for VCSEL based optical links, the design framework is organized in three levels of hierarchy. The models are developed, and implemented in Verilog-AMS. Therefore, the model parameters are fitted to measured data. A sample transient simulation demonstrates the functioning of our implementation. Suggestions for future directions in top-down methodology used for optoelectronic systems technology are also presented.

Ytterbium-doped silica fibers exhibit very broad absorption and emission bands, from 800nm to 1064nm for absorption and 970nm to 1200nm for emission. Therefore wide band lasers can be obtained using a wide variety of pump lasers. In this paper, the characteristics of high-doped Yb³⁺ fiber are analyzed and verified by experiment and a highly-doped Yb³⁺ fiber ring laser with short cavity has been presented. Comparing with normal Yb³⁺doped fiber, the relationship between the important characteristics of the Yb³⁺doped fiber laser such as threshold power, output power and laser parameters such as pump power, fiber length, output couple ratio is analyzed. Numerical results are coincident with the experiment phenomenon very well. A 1053 nm pulse has been achieved in our fiber laser. The output power is 6mW as pump power is 110mW and the slope efficiency is 17%. The Yb³⁺ fiber laser we produced can be used as a stable source in obtaining ultrafast pulse, fiber sense and optical communications.

Polyimide (PI) /silica (SiO₂) nanohybrid composite waveguide films prepared from Pyromellitic dianhydride (PMDA), 2,2-Bis(3-amino-4-hydroxyphenyl)hexafluoropropane(6FHP) , nonlinear optical (NLO) molecule, coupling agent APTES and hydrolysate of TEOS via sol-gel process and thermal imidization. The silica content in the hybrid waveguide films varied from 0 to 22.5/wt%. The PI hybrids prepared were characterized by IR, thermogravimetric analysis (TGA), X-ray diffraction (XRD), scanning electron microscopy (SEM),etc. They exhibit fair good optical transparency. The SiO₂ phase is well dispersed in the polymer matrix. DSC and TGA results show that these hybrid waveguide materials have excellent thermal stability.

Photoelastic effect which is the result of the external stress on the fiber causes inductive birefringence. In general, the photoleastic effect induces the differential group delay (DGD) between two orthogonal states of polarization (PSPs). Then the polarization mode dispersion (PMD) can be shown by DGD. In this paper, a digital emluator is present to validate a new method which uses PMD to pinpoint stress-location of optical-fiber cable .The major point about this new location method is how to pick up signal from a mass of random polarization states. Based on a waveplate model and Monte Carlo analysis, a more physical digital emulator is shown to find the possibility of the stress-location in optical fiber.

ZnO were deposited on sapphire and silicon substrates by RF magnetron sputtering from a metallic zinc target. The structural and optical propertied of ZnO films were studied by X-ray diffraction, and UV-VIS-NIR scanning spectrophotometer. XRD measurements show ZnO films had a preferential orientation along the c-axis. Only one peak, (002) phase, appears on the diffraction spectra. The transmittance spectra indicate that ZnO films possessed a transmittance of about 80% in the visible region and a sharp absorption edge at wavelength of about 390nm. The refractive index n and the extinction coefficient k are all sensitive to the oxygen partial pressure and the substrate temperature. Furthermore, based on the ideal five layers symmetrical waveguide films, the relationships of the loss and the thickness of the waveguide layer and the buffer layer were analyzed using ZnO as waveguide layer and SiO₂ as buffer layer.

The band gap characteristics of one-dimensional and two-dimensional photonic crystals made of uniaxial anisotropic materials were analyzed with a focus on the band gap characteristics as a function of optical axis orientation in the aniostropic material. For one-dimensional case, with optical axis normal to periodicity axis, the two polarization of on axis light will experience different refractive indexes and thus the degeneracy in photonic band will disappear. Theoretically we show that in some nonlinear materials, with presence of certain symmetry, the band lines correspond to two polarizations will degenerate under a high electric field. It is also shown that the gap position and size varies as the position of the optical axis varies and the range is limited by the birefringence of the anisotropic material. In two dimensional photonic crystal, we showed that, changing the position of optical axis in the propagation plane is simply change of symmetry in photonic band structure. If the position of the optical axis is varied in the transversal direction, we can open or close the band gap. The characteristic of anisotropic material, the direction dependant refractive index can be used to improve the band structure of conventional isotropic photonic crystal.

Polymeric waveguide optical CDMA encoders and decoders based on a promising coding scheme are proposed that allows significent reduction of the cross-correlation noise. The new encoding and decoding scheme is based on the orthogonal property of the eignvectors of the encoding/decoding matrices. The orthogonal property of the eignvectors ensures an untra-low cross-correlation noise level and allows several time more active users than existing systems. In this paper, polymer electro-optic waveguide optical CDMA encoder and decoder modules based on the orthogonal coding scheme are analyzed. Simulation results are presented.

Polymer films with high optical transmission have been investigated for making optical devices for several years. SU8 photoresist and optical adhesives have been investigated for use as thin films for optical devices, not what they were originally designed for. Optical adhesives are typically a one component thermoset polymer and are convenient to use for making thin film optical devices such as waveguides. They are prepared in minutes as thin films unlike SU8, which has to be carefully thermally cured over several hours for optimum results. However SU8 can be accurately patterned to form the geometry of structures required for single mode optical waveguides. SU8 in combination with the lower refractive index optical adhesive films such as UV15 from Master Bond are used to form single and multi mode waveguides. SU8 is photopatternable but we have also used dry etching of the SU8 layer or the other polymer layers e.g. UV15 to form the ribs, ridges or trenches required to guide single modes of light. Optical waveguides were also fabricated using only optical adhesives of different refractive indices. The resolution obtainable is poorer than with SU8 and hence multi mode waveguides are obtained. Loss measurements have been obtained for waveguides of different geometries and material combinations. The process for making polymer waveguides is demonstrated for making large multi mode waveguides and microfluidic channels by scaling the process up in size.

Fabrication of Polymer microlens array based on UV-molding techniques is presented. UV-molding enables for the integration of polymer microlens array on top of arbitrary substrates like glass, silicon other polymeric films. In this technique, photoresist or glass mold is first fabricated by conventional photolithnic method and subsequently served as transparent replication tool. UV curable polymer resin is then coated on patterned or unpatterned substrates and a contact mask aligner is used to align substrates and replication mold tool and then make the mold immersed into the resin. Replication of polymer on substrates is achieved by UV photopolymerisation of the resin. Resin thickness and gap distance between mold and substrate are carefully controlled in order to obtain acceptable thickness of cured polymer base. The UV molding technique was used to molding of a polymer film carring microlens array on the surface of an experimental CCD imaging sensor chip in this paper to enhance its fill factor and sensitivity.

A novel copolymer optical fiber with high azobenzene concentration is reported (more than 3.2 mol %). The orientation process of the preform was fitted with corrected bi-exponential equation. Compared with the doped one, the photosensitivity of this kind of copolymer optical fiber preform is analyzed. The influence of azobenzene concentrations and write conditions on photosensitivity of copolymerized PMMA was analyzed. Then, long-period of 120um birefringent grating was fabricated in the single mode fiber with core refractive index of 1.485 (at wavelength of 1.5um), and relative index difference delta of 0.008. The duty cycle is 50%, and the refractive index change in the exposed area is about 4*10^-4 for the ordinary or extraordinary ray.

This paper summarizes the material synthesis and properties of transparent electro-optic ceramics, namely OptoCeramic®, including PLZT and PMN-PT. Material structure, dielectric, optical and electro-optic properties are discussed. OptoCeramic materials feature in high E-O effect, low optical loss, broad transmission wavelength range, ceramic ruggedness, and low cost. A variety of devices made from OptoCeramic materials are discussed, including variable optical attenuators, polarization controllers, sinusoidal filters, dynamic gain flattening filters, tunable optical filters, and Q-switches.

In this paper, we report the design and fabrication of a long-period waveguide grating (LPWG) in a polymer ridge waveguide, which has a benzocyclobutene (BCB) core and an epoxy cladding of the same width. We first apply an accurate perturbation theory to evaluate the phase-matching condition of the grating and derive simple analytical expressions to highlight the temperature dependence of the resonance wavelength. The possibility of achieving a polarization-independent resonance wavelength is also discussed. We next describe the fabrication of an LPWG in a BCB/epoxy ridge waveguide by a UV-writing technique using a KrF excimer laser and present the transmission spectra of the grating measured at different UV dosages. By controlling the waveguide width, we produce an LPWG with a resonance wavelength that is polarization insensitive at a specific temperature. The temperature dependence of the LPWG is also discussed. Our results provide a better understanding of the operation principle of LPWGs, which should facilitate the design of LPWG-based devices for various applications.

A review is presented on some progress we have made recently in planar integrated photonics including arrayed-waveguide gratings (AWGs) and etched diffraction gratings (EDGs), multimode interference (MMI) couplers/splitters, and spot-size converters. Some novel structures and design methods are summarized and presented.

In photonic integration, high index contrast waveguides (e.g. ridge waveguides) have been widely used for interconnection and device construction because of their compactness. However, the strong confinement also means that the ridge waveguide is generally more multi-moded laterally than other waveguides of similar dimensions. A laterally single mode ridge waveguide is typically about 0.5 micrometer or less in width, which could incur high propagation and fiber coupling losses. Hence, a wider waveguide is often used to minimize loss at the expense of the single-mode characteristic, especially for long devices. However, many devices, such as Mach-Zehnder interferometers and directional couplers, require single-mode waveguides for proper operation. In these cases, the multimode waveguides can still be used if appropriate mode-filters are strategically located at the input and within the device to remove potential higher-order modes. We propose a higher-order mode filter using two back-to-back lateral waveguide tapers, which could be as short as 150 micrometers. Mode discrimination occurs in the down-taper where the higher-order modes become leaky when the taper width reaches their cut-off points (i.e., points where the modes are no longer guided by total internal reflection). The taper imposes only about 0.2dB loss to the fundamental mode itself. The up-taper at the other end restores the fundamental mode back to the original size. Simulations using Beam Propagation Method (BPM) shows that this mode filter is insensitive to the taper lengths and has reasonable fabrication tolerances.

This paper provides a description of the research for the development of an integrated high speed true-time-delay module for synthetic aperture radars. The unique feature of the approach is that the true-time-delay waveguide circuit and electro-optic switching elements are integrated. As a result this integration significantly reduces the device size while simplifying the difficult packaging problem associated with the interfaces between optical fibers and optical switches. Such a monolithic approach provides greater precision for the RF phase control that the phase control provided by fiber-delay-lines as a result to the submicrometer accuracy of lithography-defined polymeric waveguides. More importantly, the optical switched true-time-delay network requires less electrical power due to the low power consumption of electrically-switchable waveguide gratings. Furthermore, the electrically-switchable waveguide gratings have a very fast switching speed (<50 μs) that is at least 100 time faster than any existing commercial optical switching matrix.

Current technological issues arising to meet rapidly grwoing demand on 3-D measurements in the field of microelectronics packaging and integration are addressed with special emphasis on white-light interferometry. We first discuss the problem of phase change upon reflection which causes significant measurement errors unless properly compensated for measuring composite targets made of dissimilar materials. Next, an extended application of white-light interferometry is described with aims of measuring not only the surface height profile but also the thickness profile of target surfaces coated with transparent thin-film layers. Finally addressed is the dispersive white-light interferometry that draws much attention for high-speed implementation of surface metrology, which is found useful for in-situ inspection of micro-engineered surfaces.

Photo-generated carriers' transmission delay of a CMOS-Process-Compatible double photo-diode (DPD) is analyzed by using device simulation in this paper. The carriers' transmission delay of a DPD in CMOS N-well process consists of three parts: the delay in the P⁺ region, in the depletion region and in the N-well. The DPD equivalent circuit model, including photo-generated carriers' transmission delay, is given by means of device simulation. By comparing with different depth of the N-well and different area of the DPD, the delay of the diffusion part in the N-well and the delay of the junction capacitance are the most significant factors to determine the delay time of a DPD. In addition, the diffusion delay is relative to the depth, the doping concentration of the N-well and the bias. Adopting smaller size CMOS process is of benefit to improving the speed due to the shallow well, nevertheless the shallow well can cause the responsivity reduce. The responsivity reduce can be compensated by increasing the junction area.

As an optical communication component with considerable potential, the Integrated Optical Acousto-optic Tunable Filter (IAOTF) has been paid great attention in recent years. With the advantages of low insertion-loss, broad tuning range, continual electric-tuning with high speed and simultaneous multiple-channel filtering, it has promising prospect in the future in a1l-optic networks. At first, the paper introduces acousto-optic coupling principle of AOTF briefly. Secondly, it concretely analyses the existing problems and the solutions of every developing stage with the research work of our laboratory. Finally, according to the developing trend of optical communication, we put forward a simple analysis of AOTF's developing direction and the method of improving AOTF's performance.

Vertical coupling between waveguides is a critical component for three-dimensional (3-D) integrated optics. Vertical integration adds flexibility in integrating different devices that require different materials, and facilitates coupling of the miniature devices with optical fibers. We propose a systematic design of a relatively simple and versatile vertical coupler that provides not only vertical interconnection, but also mode-size transformation and polarization mode selection all in one. As a vertical polarization splitter, it separates the TE and TM polarizations onto different vertical levels of a 3-D photonics structure, and is thus uniquely different from conventional splitters based on directional couplers or other planar devices. The vertical coupler consists of a larger bottom waveguide that serves to improve the fiber coupling, and a smaller top waveguide that contains the actual photonic device. As a polarization-independent coupler the vertical coupler is shown to transfer light with more than 90% efficiency for all polarizations over a transfer length of only 150 µm. As a polarization mode splitter, the vertical coupler preferentially couples TE or TM polarization with a contrast ratio up to 20dB. This versatility renders the vertical coupler a compact and useful input-stage device that improves the fiber coupling to small active devices and also provides a mechanism of polarization control.

The high quality Ge islands material with 1.55μm photo-response grown on SOI substrate is reported. Due to the modulation of the cavity formed by the mirrors at the surface and the buried SiO₂ interface, seven sharp and strong peaks with narrow linewidth are found. And a 1.55 μm Ge islands resonant-cavity-enhanced (RCE) detector with narrowband was fabricated by a simple method. The bottom mirror was deposited in the hole formed by anisotropically etching in a basic solution from the backside of the sample with the buried SiO₂ layer in silicon-on-insulator substrate as the etch-stop layer. Reflectivity spectrum indicates that the mirror deposited in the hole has a reflectivity as high as 99% in the range of 1.2~1.65 μm. The peak responsivity of the RCE detector at 1543.8 nm is 0.028 mA/W and a full width at half maximum of 5 nm is obtained. Compared with the conventional p-i-n photodetector, the responsivity of RCE detector has a nearly threefold enhancement.

Solid state optical gyrometer is a novel integrated optical gyrometer which consists of a waveguide coil fully integrated on a substrate. The planar coil design implies waveguide crossings, so called X-junction. X-junctions are loss generating. In this paper, the power loss of X-junction is simulated by beam propagation method. The relationship between the power loss and the intersection angle is illustrated, and the power coupling corresponded with the intersection angle is given. The simulation shows the power loss due to the X-junction could be neglected by increasing the intersection angle properly.

Optical absorption, excitation and emission spectra of Nd³⁺ in PLZT ceramics have been studied. Based on the Judd-Ofelt (J-O) theory, the J-O intensity parameters are calculated to be Ω₂=0.7199x10^-20 cm², Ω₄=1.045x10^-20 cm², Ω₆=0.9234x10^-20 cm² from the absorption spectrum of Nd³⁺-doped PLZT. The J-O intensity parameters have been used to calculate the radiative lifetime (0.385 ms) of the excited ⁴F_3/2 level. The stimulated emission cross-sections and the fluorescence branch ratios for the ⁴F_3/2 -> ⁴I_J transitions are also evaluated. We have also measured 1.068 mm fluorescence lifetime (0.168 ms) and calculated its Quantum efficiency (0.44). Under 807 nm excitation, the green and red upconversion luminescence from Nd³⁺ centers in the ceramic was observed at room temperature. Analysis reveals that Nd³⁺-doped PLZT is promising for the use as efficient optically amplifying or zero-loss electro-optical devices in telecommunication networks.

In this paper, the photo-detected and controlled functions based on silicon photo-electronic Lambda transistor (PLBT) are reported. PLBT is composed of a npn vertical bipolar transistor as main device and a enhancement-mode MOSFET transistor as feedback device which connected in parallel across the base and collector terminals of bipolar transistor. Photo-electronic-lambda bipolar transistor (PLBT) is one important member of Si-photo electronic negative resistance devices. It has wide applications in photo-electronic coupler, light detector, light sensor and other photo-electronic circuit modules, which is significant for the further study of photo-electronic devices and circuits. When the Si-photo-electronic negative transistor device works as a load, it has two stable output states (bistability characteristics) with the change of the input light signals. Using the photo-bistable and self-locking characteristics of the PLBT, a photo-controlled Bistable Logic Circuit Element has been set up successfully. Through detail studying and analyzing to the operation feature and load feature of the photo-controlled bistable circuit, the nonlinear characteristic of the circuit is demonstrated. Furthermore the applications of this circuit element have been studied and verified.

A curved image plane is usually used in a conventional Rowland-type AWG. For some applications (e.g., sensing), a straight image plane is desirable so that the output field at the image plane can be received directly with a detector-array. If one simply chooses a flat output plane (instead of a circular output curve) without optimization for a conventional AWG of Rowland circle type, some considerable aberrations will be introduced, which degrade the performances of the AWG. The aberrations are calculated and analyzed with an optical path function. A three-stigmatic-point method is used to optimize the design of an AWG with a straight image plane and minimize the aberrations. In this design, the aberrations at three special wavelengths are removed. The first order aberrations at all wavelengths are also eliminated. An 80-channel flat-field AWG is designed as an example. The results show that the aberrations are reduced greatly and a good spectral response with tolerated side-lodes is obtained.

In this paper, a novel all-fiber Q-switched single mode Er/Yb co-doped double clad fiber ring laser operating in 1548.11nm is reported, which exploits fiber Bragg grating Sagnac loop mirror as a wavelength-selective device. To obtain higher output power, the laser is pumped by six CW laser diodes operating at 976nm through six pigtails of a Tapered Fiber Bundle connected with the EYDF. When the pump power is 718.9mW, stable self Q-switched pulse series with pulse width of 2.8μs, repetition rate of 50kHz and peak power of 274.3mW are achieved. Self mode-locked pulse is also obtained in such experimental setup.

In this paper, a new and simple numerical computational method simulating the gain characteristics of erbium and ytterbium co-doped phosphate glass waveguide amplifier is presented. This algorithm is the wavelets based Finite-Differences Time-Domain Method, which takes advantage of compression properties of wavelet transforms. Especially multi resolution analysis (MRA). Simulation results show the validity of the algorithm.

We present a novel numerical model for an ytterbium-doped fiber ring laser. A comprehensive numerical model based on an iterative solution of propagation rate equations is used to analyze the impact of various laser variables. The dependence of laser output power on pump power, ytterbium-doped fiber (YDF) length, and emission wavelength has been investigated, with the aim to optimize laser parameters with respect to emission wavelength and output power. Close to emission wavelength, the optical signal-to-noise ratio is higher than 65 dB. We also investigate that the initial oscillation is damped oscillation, and the laser output become steady-state output one millisecond later.

SM-LDV (Self-Mixing Type Laser Doppler Velocimeter) using single mode VCSEL (Vertical Cavity Surface Emitting Lasers) has many characteristic such as high accuracy of velocity measurement, low power dissipation and low cost. The saw-tooth waveform of Doppler signal can be used to discriminate the motion direction. Because of low light power of single mode VCSEL, the backscattered light is so weak that the saw-tooth waveform is not good enough to discriminate the motion direction. SM-LDV direction discrimination using single mode VCSEL modulated by triangular wave is not obviously dependent on the light power of Laser and its reliability is better. The dynamic range is very narrow when the VCSEL is modulated by constant frequency triangular wave. We present a method that VCSEL is modulated by triangular wave whose frequency is tracking the divided frequency of Doppler frequency shift (fD) and it can expand the dynamic range more than one order of magnitude. The results show that the dynamic range of direction discrimination can reach 5-500mm/s when the wavelength of single mode VCSEL is 850nm and the operating current is 8.6mA, the frequency of triangular wave is fD/16,the modulation current of triangular wave is 0.042mA.

The experiments show that the single-mode vertical-cavity surface-emitting laser (VCSEL) Laser Doppler Velocimetry (LDV) is better than the multilongitudinal-mode laser diode LDV in many characteristics, such as the accuracy of velocity measurement and the temperature range of the laser. Because the output power of the single-mode VCSEL is very low and only 0.7mW, the backscattered light received by the photodiode in the laser house is so weak that the signal-to-noise ratio (SNR) of Doppler signal is low. And the Doppler signal spectrum width spread and amplitude modulation envelope badly influence the velocity measurement accuracy. Analog phase-locked loop (PLL) has many characteristics, such as narrow band tracking filter, locking the signal with peak voltage and high rejection ratio of amplitude modulation. Using the analog PLL, the SNR of Doppler signal and the velocity measurement accuracy can be improved obviously. But because the locking range of the common analog PLL is narrow, we use difference frequency analog PLL to expand the locking range, and the dynamic range of velocity measurement can be greatly expanded. As a result, the velocity measurement accuracy of the single-mode VCSEL self-mixing LDV is better than 1% when the velocity range is from 30mm/s to 480mm/s.

Large mode area (LMA) Yb-doped double clad fiber lasers with high power are theoretically and experimentally investigated. For a Fabry-Perot cavity structure, we show the dependence of output power on the output mirror reflectivity, coupled pump power and fiber length, respectively by using power propagation equations and rate equations. Stable CW operation of the fiber laser at 1064 nm with maximum power 4.6 W and slope efficiency 82.6% is achieved in the experiment.

The extreme divergence and the astigmatism of the high power laser diode array (LDA) require optics with complex lens structure and high performance. A monolithic micro- optic system is designed to shape the beam of LDA and couple the output of LDA with low NA fiber. The structure and principle of the micro-optic system is described in detail. The actual performance of the micro-optic system is studied by measuring P-I properties for both fiber coupled output and the LDA output, and their dependences on deviations in x, y, z directions. The light output of 980nm, 19-emitter LDA is shaped by this micro-optic system and coupled into a fiber with 400µm diameter, Numerical Aperture (NA) 0.22. The overall efficiency is more than 60%. The main factors effecting coupling efficiency are analyzed.

Recently, the scheme of bi-directional optical communication with a mutual-pumped phase conjugate mirror (MPPCM) has attracted attention. Bi-directional communication enables the integration of devices because input port and output port can be shared. We propose a new design for all-optical bi-directional interconnection with double MPPCMs. This interconnection is composed of two photorefractive crystals and a polarized beam splitter which is located between two crystals. The bi-directional connection is formed via two MPPCMs produced by illumination of the signal beams and the control beam. In this interconnection, the wiring pattern can be reconfigured flexibly by changing the spatial distribution of the control beam without any adjustment of the signal beams. The signal beams and the control beam are orthogonal polarized, so the signal beams can be transmitted without energy loss in dividing with control beam. In addition, the signal beams transmitting through the two crystals enhance the MPPCMs efficiently under the appropriate condition. After the buildup of MPPCMs, the connection is maintained without consecutive illumination of the control beam. Therefore the self-holding is achieved and it enables the interconnection with lower power consumption. In this paper, we analyze the optimum intensity ratio of the control beam for the signal beam in order to obtain high connection efficiency. Moreover, we confirm the self-holding of connection experimentally using BaTiO₃ crystals and Ar⁺ laser without consecutive illumination of the control beam and show the connection can be maintained for several hundred times as long as the time constant of the crystal.

Position sensitive detectors (PSD) use the lateral photo effect to determine the centroid position of an incident light spot focused on it. A 65-pin ceramic packaged 4×4 arrayed position sensitive detector was fabricated first time as a new prototype of Hartmann-Shack wavefront sensor. The detector, consisting of 16 tetra-lateral sensitive areas, is a p-n-n+ configuration made on 3-inch <111> n-type high resistance crystal silicon substrate. A 100nm antireflection SiO₂ thin film was formed on the surface and a multi-layer cover glass with transmissivity > 98% from 400nm to 950nm. The main parameters of the arrayed as wavefront detector, such as reverse voltage, dark current photosensitivity, response time were reported in the paper.

One-dimensional magneto-optical (MO) photonic crystals display enhanced MO effect due to the localization of light, it can be used to fabricate small-size optical isolator with only tens of micros which can enlarge the integration of system. A transfer matrix method (TMM) that is suitable for solving the problems of the propagation of polarized light in anisotropic media at an arbitrary incidence angle, is described detailedly in this paper. Using this method, we discussed two types of reflection-mode "sandwich structure" of MOMF isolator, and found that the structure with thicker MO layer has advantages in working stability and fabrication.

The optical reflector based on two-dimensional photonic crystal constructed by a square lattice of dielectric rods has already been reported in recent years, But the enormous difficulties to fabricate this structure are well-known, because the height of the rods must be finite in a real system so in this case no guided modes appears when air waveguides are created. On the contrary, there is not this inherent limitation for the photonic crystal waveguide made of air holes. In this paper, I will demonstrate an optical reflector based on photonic crystal,which constructed by air holes introduced into high index material. We design a monomode waveguide with even symmetry and discuss the characteristic of the reflector obtained by inserting several defects into the monomode waveguide in FDTD method.This kind of reflectors still have guided mode even if it possess finite thickness. This will make optical reflector based on two-dimensional photonic crystal nearer to practical application.

A design idea of extended blue NEA GaAs photocathode is given in this paper. A new structure is presented by changing the composition of GaAlAs in grads in order to get the short wavelength response and in the same time to reduce the stress in the photocathode material, so that an extended blue GaAs photocathode with a higher sensitivity of image intensifier can be obtained. Finally, the spectrum responses of both ordinary and extended blue GaAs image intensifier are given, the relationship of material structure and the result of blue extending is discussed.

Recently, the propagation characteristics of waveguides or fibers filled with homogeneous chiral media were studied widely. But most of the chiral molecule was at the state of liquid. So further basic research and application research has been restricted and seeking suitable solid chial material was becoming the key of minimizing and practical development. One way of manufacture solid chiral material is sol-gel method. In this paper, using TEOS, C₂H₅OH and N, N-dimethyl formamide dimethyl aceta as precursor, the chiral molecule C₁₇H₁₇ClO₆ was uniformly incorporated in gel by sol-gel process. So the sol-gel material containing C₁₇H₁₇ClO₆ was fabricated successfully. Its polarization response was investigated. By using several different kinds of light sources which own different wavelength, we test the optical rotatory dispertion of chiral sol-gel material containing C₁₇H₁₇ClO₆. By calculation, we obtain chiral parameter at different optical wavelength. In order to find out which state the chiral molecule C₁₇H₁₇ClO₆ maybe in the sol-gel material, the infrared absorption spectra are measured.

We report on a theoretical analysis of a channel dielectric waveguide consisting of periodically interlaced negative refractive index medium and positive index medium. The dispersion relation for TM modes is obtained. The properties of guided wave modes have been numerically disclosed. It is shown that the waveguide can exhibit negative group velocity dispersion as well as extraordinarily large group velocity dispersion. The Poynting vector within the waveguide can change both sign and magnitude. The distribution of energy flux density of different sections relates to the frequency and the width of the channel waveguide.

This paper studies testing technology of photoelectrical transmittivity, analyses the reason of error occurred in testing system, and find out the method for resolving it. It is high automation and accuracy than traditional methods. The system uses parallel light-pipe as lamp source, which is revised by correction filter, to obtain the white light of approaching visible spectrum trait. The white light is divided into two lights: reference light and measuring light. Reference light is coupled to modulator by optic fiber coupling device, modulator turns it into fixed frequency light and then it enters integral ball through ancillary lens. After measuring light passes by testing-piece, it is assembled to modulator by collector lens, modulator turns it into particular frequency light and then it enters integral ball through ancillary lens. The lights diffused reflection heaps of times in integral ball become the equality lights and are in proportion to flux of incidence. Electric eye converts light signal to electric signal. The electric signal contains two frequency signals, it is magnified by synchronous amplifier, and at last gains the electric signal in proportion to the light from pupil.

In this paper, optical trigonometry measurement principle and wok principle of linear CCD are introduced, which are based on to design optical focusing and imagery system with He-Ne laser instrument as illuminant. peripheral circuit of linear CCD is designed in theory and experiment. non-contact thickness measurement instrument is constructed, using CCD as photoelectric transformation element and microprocessor as the controller. The principle of measurement system is inclined trigonometry measurement principle and CCD is photoelectric transformation element. The time order driving circuit of CCD is designed.

Long wavelength InGaAs/InGaAsP multiple quantum well laser is grown by MOCVD. The characteristics of spontaneous emission, amplified spontaneous emission and modal gain of the MQW is investigated by using single-pass multi-section technique. The amplified spontaneous emission is around a wavelength of 1500nm, dependent on the temperature and the current density. The modal gain spectra show a red shift with increasing temperature. The peak modal gain exhibits a decrease with increasing temperature from 140K to 300K. The loss measurements shows that the main loss mechanism in the structure might be the free carrier absorption in the doped cladding layers and a internal modal loss of about 10cm^-1.

A series of image processing methods of fringe analysis is given, which is important for the interference fringes. Through image smoothing course such as homomorphic filtering and thresholding, then thinning, disbranching with chain, fitting, a single-pixel fringe can be obtained, which will be prepared for the coming computing the tested parameters. All which have been proved by experiments.

Theoretical study and simulation research on atmospheric effect in airplane-ground laser communication are developed in this paper, which establishes refraction, attenuation and turbulence models of laser atmospheric transmission, uses communication speed and error rate as objective function to do digital simulation research for the whole communication process based on theoretical model of laser communication system. In simulation, various picture tools are used for observing the changing of laser energy with external environment effects, such as atmospheric effect, free-space loss, background radiation; as well as observing laser beam position and energy distribution when laser arrives at the satellite receiver. Moreover, local simulation model is established for analyzing thoroughly effects of various external factors to the laser communication performance.

Computer simulation theory and realization of Acquisition, Pointing and Tracing (APT) for laser beams is discussed in this paper. It includes two aspects: I. function Simulations on APT corresponding module units, which focus on the relationship among initial pointing uncertainty, acquisition probability, scanning pattern, CCD detect signals and facula position error. II. HLA (High Level Architecture) application, which uses three unattached machines to represent two communication terminals and satellite's independent movement, gives the simulation federate design, object design and realization. This simulation scheme can simulate open loop process of APT system perfectly, realize the distributed APT simulation, and improve the confidence. Moreover, combined with the three-dimensional engine, it shows the APT process visually and vividly.

Heat sinks with impedance matching circuit have been designed and fabricated for the packaging of high-speed electroabsorption (EA) modulators. Ti/Cu/Ni/Au metallization system is adopted for the coplanar waveguide (CPW) electrodes and a 50-ohm Ta₂N thin-film resistor in parallel with the EA modulator is used for impedance matching. By a matching resistance optimization, a reflection coefficient S11 better than -21 dB has been demonstrated up to 40 GHz. The heat sinks are applied successfully in the 40 GHz Modulator packaging.

Based on the difference of photonic band structures between TE and TM polarization modes in periodic multiplayer and the combining effect of one-dimensional (1D) hybrid dual-periodical photonic crystals (PCs), a novel method to design polarization band-pass filters used in wavelength division multiplexing system is presented. Such the polarization band-pass filters can be fabricated by dual-periodical TiO₂/SiO₂ thin film PC structures and theoretical calculation shows that they can have excellent optical properties with TM polarization transmission and TE polarization reflectance. And we try to physically discuss and explain the relation between the parameters of PC heterostructures and the optical characteristics of the filters, such as the number of TM polarization passbands, peak transmittance, half-band width and rejection and so on.

A novel digital micro-machined variable optical attenuator (VOA) capable of 40dB dynamic range is described. The device consists of an electromagnetically actuated shutter interposed in a fiber collimator gap and allows adjustment of optical attenuation stepwise in response to inputting TTL pulses. A linear response with respect to driving pulses was achieved by incorporation of a compensation mechanism in the design. Measured performance of the VOA is reported and the characteristics of the device were analyzed with a numerical simulation based on scalar wave theory. The VOA is scalable to a discrete array for the implementation of channel equalization in WDM systems for the realization of high capacity cross-connects.

Our configurable optical add/drop multiplexers (OADM) are based on thermally tunable silicon-on-insulator(SOI) Bragg gratings. We have simulated the whole device and get ideal performance. We also tried experiments to explore the process of grating waveguide and got useful results.

This paper discussed CCD used for faint target detection in clear sky, realized detection of the contrast less than 0.006. In order to improve CCD'S detecting capacity, the spectrofilting technology is used to raise the contrast of target to background Research has proved that speatrofilting can improve the contrast of faint target with stable and obvious effect, and provide theoretical basis for CCD used to detect faint target.

With the development of high performance focal plane arrays (FPAs) which provide very good sensitivity, operability, and excellent image quality, FPAs are applicable to wide-field-of-view, long range surveillance and targeting missions. However, many applications, like space- and air-borne surveillance telescopes, emphasize wide field of view (FOV) over resolution, permitted the most rapid survey of the entire field of regard. This is typically limited by large, complex, and costly corrector optics to flatten the wavefront. An alternative approach is to design a curved focal plane to alleviate the designing burden of optical system. Conventional approach is by the way of providing the ability to produce FPAs with a specified degree of curvature while preserving required electro-optical characteristics. This paper presents a novel method by utilizing spot-to-curved-line converter based on normal FPAs.

The measuring way of verticality of elevator's guide way is studied in this paper and a measuring apparatus is made too. The apparatus regards the laser beam, emanating from the laser device, which can emit the perpendicular laser to the earth, as the measuring norm. The facula on the autodyne, which clings to the guide way during the measuring, is sampled to computer with a CCD camera and an image acquisition card. By computer image processing, the measuring apparatus can identify the displacement of the facula center. By this way it determines the verticality error of the guide way at the measuring position, which can be recorded automatically at the same time. For the facula after threshold segmentation, the apparatus can recognize it automatically. If it is circular, its center can be worked out by centroidal equation; if it is cirque, after edge detecting, its center can be figured out with Hough transform. For the Hough transform of circle, the dimension of its parameter space can be brought down from 3 to 2 with the derivative of the circle equation and thus its calculating quantity can be reduced greatly. The measuring way is proved by testing that it had improved more greatly and is more accurate, faster and simpler than ever before.

The availability of the E-band with full spectrum fiber is possible by a new fiber manufacturing process. This increased bandwidth let the full spectrum fiber superior choice for metropolitan and access optical networks. In optical fiber application, the hydrogen aging effect is important factor in the long-term reliability of an optical fiber. In this work, we report a test results for hydrogen aging effect of full spectrum fiber. The attenuations of the fibers are varying even in a hydrogen-free environment after aging test. It is also found that so small bending of full spectrum fiber in hydrogen aging test chamber cause significant variations in optical characteristics.

In this paper, a new converter for plastic optical is proposed .The whole system is divided into 5 parts and each of them are introduced. In this experimental system, the M array is used to replace the actually data sources. Then change the M array into the CMI code. Through the optical-electric transmission part, the signals are sent to the CMI decode part in which the original M array is recovered. The circuit board by which the data signals can be transmitted has been achieved in lab. The parameters of the system are discussed. The relationship between the system clock and BER(bit error rate) is analyzed. Several different factors which have effects on the system's performance are discussed. In order to patch with RJ-45, the further work mainly focus on the connection with the nowadays netcards which are widely used in PC and LAN.

A design of micromachining based direct-coupled variable optical attenuator (VOA) is presented. The device, fabricated by using CNC engraving and laser spot welding techniques, operates by misaligning a fiber-to-fiber coupling through a lateral displacement of one of the fibers mounted on a micro-machined flexure driven electromagnetically. An FET software package ANSYS was employed to optimize micro-mechanical structure and simulation of the device operation was described in detail. The measured performance of a VOA prototype is reported, featuring a fast dynamic response (<2.3 ms), great dynamic range (0~65dB) and wide bandwidth.

The planar lightwave circuit (PLC) on silicon substrate offers a promising on-chip integrated solution to polarization-mode dispersion (PMD) compensation for long haul high speed communications. A novel cascaded PLC based PMD compensator is proposed in this paper and a detailed statistical analysis of PMD generated by cascaded PLC circuits is presented. Using Gisin and Pellaux's approach the distributions of first-order PMD produced by various multiple-stage PLC circuits were obtained by Monte Carlo simulation with respect to the phase shift introduced by heating elements in the circuits. The generated PMD was compared with a standard Maxwell distribution and that of a 12-stage nonlinear crystal based PMD compensator. It was found that a 3-stage cascaded PLC circuit yields a performance close to that of the crystal-based PMD compensator, while with a significant reduction in packaged size and enhancement in stability.

The characteristic of polarization of random laser is investigated by numerical method. We use the random laser model coupling semi-classical laser theory with Maxwell's equations. The model couples electronic number equations at different levels with field equations. The equations are solved by finite-difference time-domain method. We calculate the evolvement of transverse electric wave and transverse magnetic wave in a two-dimensional laser system, respectively. We draw conclusions as follows. Polarization influences the frequency and the position of mode in a random laser system. The threshold is affected by polarization as well.

We use the semi-classical random laser model, which is described by the Maxwell equations and the rate equations, and utilize the finite-difference time-domain method (FDTD) to investigate the differential characteristic of one-dimensional random laser. The results of the calculation indicate that emitting frequency changes continuously with the slight modification of the thickness of film. Thereby, the random laser is a stable system, not a chaotic system. Those thin films in the center of localized regime have stronger effect on the emitting frequency than those beyond the position of localized regime. The thin films in the center of localized regime form a resonant cavity actually and those thin films beyond the position of localization form reflecting mirrors of cavity. Modifying the thickness of the thin films in the center of the localized regime mean modification of the length of cavity, consequently the emitting frequency is changed. Modification of thickness of the thin films out of localized regime mean change of the reflectivity of the reflecting mirrors of cavity. So it has no effect on the emitting frequency, but it affects the emitting energy of laser. If the modification of the thickness is very great, it maybe changes the position of the localized regime and the emitting frequency of mode.

GaAs PCSS's can work under linear and nonlinear modes. When the PCSS's work at the field below 3.5 kV/cm, current pulse string and corresponding light pulse string have the same rise time and pulse width. The resistance of PCSS's recovers, as soon as the light pulse disappears. When the electrical field is larger than 4.3 kV/cm, the light energy is greater than 0.46 mJ, GaAs-PCSS's work at nonlinear mode, which also is called high gain mode or lock-on effect. By calculation, Gunn domains come into being in GaAs in lock-on effect, and the high-gain mechanism is explained by optically activated charge domain model. So the microcosmic conditions of lock-on have been found. The requirement on the triggering laser energy is essential to meet the requirement of Gunn-domain formation by generating enough carriers. The requirement on the electrical field threshold is borne on the requirement of NDR threshold (Gunn threshold), which ranges from 3.2 kV/cm to 4 kV/cm for GaAs. In our experiments, the electric field threshold of high-gain mode is from 4.1 kV/cm to 11 kV/cm, which is higher than NDR threshold of GaAs. We can reduce the electrical field down to Gunn threshold by designing the external circuit. In this paper, two circuits are introduced which is designed by Sandia National Laboratories, and can be used to induce fast recovery from lock-on.

Monte-Carlo method is adopted in GaAs PCSS's simulation, In the case of high optical fluence, space-charge field can intensity influence the movement of the carrier. Thus, space-charge field can intensity influence not only the shape of photo-electric current of PCSS's, but also the terahertz out put of photo-conducting antenna. In this paper, the forming and movement of space-charge field are simulated by means of Monte-Carlo method. And the result of simulate indicates that optically activated charge multi-domain exists in photoconductor. The forming of multi-domain is also explained in this paper.

We report the experimental results of a large-aperture biased semi-insulating GaAs photoconductive dipole antenna, with a gap of 3 mm between two Au/Ge/Ni electrodes, triggered by 800 nm Ti-sapphire laser pulses with 82 MHz repetition rate. A direct comparison is made between insulated GaAs dipole antenna with a Si₃N₄ layer and bare GaAs dipole antenna. The radiation amplitude present linear to the exciting power when the applied voltage is fixed. The Si₃N₄ insulated GaAs dipole antenna can hold higher biased voltage than normal GaAs dipole antenna; its terahertz radiation generation efficiency is significantly higher than normal GaAs dipole antenna. The maximum voltage can be hold by the Si₃N₄ insulated GaAs dipole antenna is about 2 times higher than normal GaAs dipole antennas. We simulate the THz radiations from insulated GaAs dipole antenna with Si₃N₄ layer and bare GaAs dipole antenna. The waveforms of the simulated normalized surface field are in close agreement with the waveforms of the experimental results.

A novel design of micromachining-based high speed 1x2 optical switch array is presented. Employing a triangle-shaped micromachined mirror for beam directing, the design achieved a high level integration of multiple switches on a single substrate, significantly shortened switch time to below 1 ms. An array of four 1x2 switches was fabricated and the performance of the switch array prototype was reported, attaining a fast switch time of less than 750us, extremely low cross-talk <-70dB, an insertion loss of between 0.6 and 0.8 dB, and with an overall size of only 60×36×7 mm³. The experimental result was compared with that from a finite element analysis and a good agreement was obtained.

In this paper we researched principles of three-dimensional (3-D) isotropic acousto-electro-optic (AEO) modulator, including coupled wave equations and diffraction efficiency formula of the 3-D AEO effect. The AEO crystal is worn into a column of six side-faces. Three transducers are stuck on adjacent side-faces and they can produce three acoustic energy channels of 60° each other in acoustic plane. Direct current (DC) electrodes with central holes are plated on the end-faces. Through the hole, incident light propagates along axis of the column, which is perpendicular to the acoustic plane. So the acousto-optic (AO) effect must be Raman-Nath effect, it can realize 3-D light deflection. The DC electric field is supplied along the axis of the column too. So the electro-optic (EO) effect must be longitudinal, it can realize light modulation. We designed and made a 3-D isotropic AEO modulator of centre frequency 50 MHz using Potassium Hydrogen Phosphate (KDP) crystal, and measured its modulation curve of relative diffraction efficiency vs DC voltages. Measured results agree with theoretical calculation. Multi-dimensional AEO modulator has applications in multi-channel optic communication and optic signal processing.

In this paper, a specialized instrument of measuring inclination and deflection is proposed, which is developed by adopting photoelectric detection technique combined with design technique of precision instrument. This instrument adopts one-dimensional position sensitive detector PSD as the sensor of position, using simple pendulum structure to measure the inclination between a surface being measured and the earth's core. the measuring principle, structural design of the instrument has been introduced. It makes emphasis on the application research of the position sensitive detector PSD based on photoelectric transform, the research of high-accuracy data acquisition and processing technique, the linearization calibration method of PSD, etc. The measurement result can be shown directly on liquid crystal display, at the same time, for being convenient to communicate with the computer, the instrument also can send measurement data by infrared transmission and the computer can gather the data by the same means. This clinometer is of simple structure, high response speed , high measuring accuracy, strong interference rejection ability , low consumption , high characteristic of performance-cost ratio.

A compact polarization-insensitive 8×8 arrayed waveguide grating with 100GHz channel spacing at 1.55µm is presented on the material of silicon on insulator (SOI). Increasing the epitaxial layer thickness can reduce the birefringence of the waveguide, but the wvaeguide's bend radius also increases at the same time. We choose the SOI wafer with 3.0μm epitaxial layer to reduce the device's size and designed the appropriate structure of rib waveguides to eliminate the polarization dependant wavelength shift. Compared to the other methods of eliminating the polarization dependant wavelength shift, the method is convenient and easy to control the polarization without additional etching process. The index differences between TE0 and TM0 of straight and bend waveguides are 1.4×10^-5 and 3.9×10^-5, respectively. The results showed that the polarization dependant wavelength shift is 0.1nm, and the device size is 1.5×1.0 cm².

In this paper, a LiNbO₃ optical-fiber modulator with CPW electrode is discussed. Being use the LiNbO₃ optical fiber as the transmission channel of light in this structure, the modulator has less LiNbO₃ than the conventional LiNbO₃ waveguide modulator. It effectively decreases the effective dielectric coefficient of microwave and realizes velocity matching and low half-wave driving voltage. The characteristic impedance, refractive index and bandwidth of the modulator have been derived using finite element method. The optimal structure of modulator is presented.

An enhanced technique for interrogating fiber Bragg grating wavelength shift using cascade wavelength division multiplexer(WDM) couplers was proposed and demonstrated. Three WDM couplers which show a linear filter function over the expected wavelength range are employed and cascaded to track Bragg wavelength shifts. Compared with single WDM demodulator, sharper spectral slope is obtained and considerable linear filter range is kept. The static and dynamic strain sensor demodulation experiments demonstrated that the simple passive technique improves the sensitivity approximately two times and keeps 5nm linear demodulation range based on our devices. The cascade WDM coupler demodulation system has high scan rate which can be used to monitor fast vibration.

A high bit rate more than 10Gbit/s optical pulse generation device is the key to achieving high-speed and broadband optical fiber communication network system .Now, we propose a novel high-speed optical transmission module(TM) consisting of a Ti:Er:LiNbO3 waveguide laser and a Mach-Zehnder-type encoding modulator on the same Er-doped substrate. According to the standard of ITU-T, we design the 10Gbit/ s transmission module at 1.53μm on the Z cut Y propagation LiNbO₃ slice. A dynamic model and the corresponding numerical code are used to analyze the waveguide laser while the electrooptic effect to design the modulator. Meanwhile, the working principle, key technology, typical characteristic parameters of the module are given. The transmission module has a high extinction ratio and a low driving voltage, which supplies the efficient, miniaturized light source for wavelength division multiplexing(WDM) system. In additional, the relation of the laser gain with the cavity parameter, as well as the relation of the bandwidth of the electrooptic modulator with some key factors are discussed .The designed module structure is simulated by BPM software and HFSS software.

We present an all-fiber G-T resonator formed by cascading two fiber loop mirrors. Based on the superposition theory and the transfer function, the wave filtering and nonlinear phase feature of the all-fiber G-T resonator is studied and the related phase shift formula of the output beam is derived. The effect of the parameters on the phase characteristics are analyzed. An novel interleaver based on the all-fiber G-T resonator is designed. The theoretic model is simulated and calculated to meet the need of the flatness and the sharpness in the 50GHZ DWDM systems.

A design of spectrometer is presented, which uses a holographic grating and a two-dimensional color CCD camera connected with PC via video format port. And in the image post-procession, a real-time frame calculus technique and a non-linear filter were applied to provider higher image quality and better resistant to background noise. With improved designed zoom mechanics, the device has a wide resolution dynamic range and high frequency, since it can gather more spectrum information than linear black-white CCD. The spectrum analysis experiments for water quality detection indicate that the device can meet variant requirements of analysis at low cost.

Microcavity structures are widely utilized as resonators in many optoelectronic devices to improve their optical performance. We present an analytic approach to study the angle-dependent properties in active microcavities with dielectric Bragg reflectors. Based on the hard mirror (HM) model and paraxial propagation approximation, the angle dependent resonance properties can be expressed analytically in virtue of the cavity parameters and incident angle. Making use of these expressions, we found both the position of the active layer and the configuration of dielectric Bragg mirrors contribute to the angular characteristics of resonance in the active microcavity. The varying trend of the standing wave effect, intracavity electrical field and the degradation of quantum efficiency due to different incident angle are discussed in detail. It's found that there exists an optimal cavity configuration where the enhanced intracavity resonance can keep high value within a broader incidence range. Then further performance optimization of the whole devices can be performed.

A chip-to-chip optical interconnection solution on PCB is presented in this paper. Both electrical and optical interconnections are used in common printed circuit board (PCB) to construct electro/optical PCB (EOPCB). An additional optical layer with waveguide structure is used in the PCB. So the EOPCB integrates the information medium "light" into the board. Optical transmitter is vertical cavity surface emitting laser (VCSEL) array. Optical receiver is PIN array. VCSEL array with its driver IC chip and PIN with its receiver IC chip are bonded with LSI chip by ball-grid array (BGA) technology. Then the LSI chips with VCSEL and PIN arrays are bonded on PCB by surface-mount technology (SMT). Multimode waveguides are used as optical layer in PCB. In order to couple light beam between optical transmitter/receiver with waveguide layer, a direct coupling method by the waveguide with 45° end face is presented. VCSEL chip is placed close to the 45° end face of the waveguide. The light beams from VCSEL array are emitted into the 45° end face directly and reflected by 90°, then coupled into the waveguide layer. No microlens arrays are needed for collimating light beam array in this configuration. A proof-of-principle experiment is made to verify the feasibility of this approach.

This paper presents a theoretical and numerical analysis of polarization properties used as Doppler velocimetry in Vertical-Cavity Surface-Emitting lasers. A good match is found between numerical results and reported experiment results. We show that condition of generating square waves is the VCSELs must operated inside the bistable region and frequency difference between two linear polarization modes is equal to several certain values. We can select proper VCSELs which frequency difference between two linear polarization modes is multiple of ±3G to obtain asymmetric waveform of self-mixing signal.

Inexpensive PMMA based Polymer Optical Fiber (POF) has the feature of a large core diameter, high numerical aperture and great flexibility, thus allow low connection cost and cheap LED source. These advantages make it a promising candidate for short distance communication. In this article, coarse wavelength division multiplexing (CWDM) test was performed with commercially available POF using its low loss transmission window. Light of two different wavelengths (650nm and 530nm) were sending on a single POF. Here 650nm red light was used for duplex IP data digital signal transmission and 530nm green light was used for voice signal transmission. Light sources are LEDs. A POF Coupler (Splitter) of 1:1 ratio was employed as multiplexer and prisms were used for demultiplexing. The channel isolation and insert loss of both channels were measured, for 650nm channel they are 20.5dB and 17.65dB, for 530nm channel they are 19.16dB and 20.55dB.

Azobenzene polymers show large optical anisotropy, and one can control the optical anisotropy by changing the alignment of the molecules with light. Azo groups fall perpendicularly to the direction of the electric field vector of the linear polarized light by photoisomerization. This reorientation induces anisotropy and the difference of refractive index parallel and perpendicular to the irradiating laser polarization direction. In this paper, the photoinduced birefringence induced with 532 nm light in films of azobenzene polymer has been studied as a function of temperature, light intensity. From the evolution of the birefringence induced by laser, the temperature effects on photochemical trans-cis-trans isomerization cycles have been probed and analyzed. The effect of laser-induced heating has been introduced to the buildup of photoinduced birefringence in azobenzene-side-chain copolymer. The curves for the buildup of birefringence were fitted with a modified function, namely, biexponential curves and Gaussian curves. The relationship of each parameter has been also presented. With the modified fitting function, we obtained better fitting result.

Multimode interference optical pulse power splitters for 1.053μm wavelength have been designed in this paper. The guided mode propagation analysis method is used to analyze the working principle of MMI power splitter. We designed the power splitters base on the analysis. Then finite difference beam propagation method (FDBPM) was used to analyze the splitting performance of the devices. At last, we analyzed the temporal performance of the device (such as pulse broaden) working for optical pulse input with the Finite Difference Time Domain (FDTD) method. The dispersion properties for ultra short 1.053μm optical pulses input were analyzed.

The theoretical spectral response formula of the PIN Gallium phosphorus photodetector is given. At the same time, considering the process requirements, the optimum device structure parameters of GaP photodetector are obtained by numerical calculation and simulation. Under the condition of these structure parameters, the responsivity of the GaP photodetector will be obtained at a given wavelength.