This PDF file contains the front matter associated with SPIE Proceedings Volume 7516, including the Title Page, Copyright information, Table of Contents, and the Conference Committee listing.

We experimentally demonstrate a compact third-order silicon microring add-drop filter with high extinction ratios. Perimeter compensation method was applied to solve the coupling induced frequency shift (CIFS) problem. After carefully design and accurate fabrication, extinction ratio up to 30dB and 40dB are measured at through and drop port, respectively.

The birefringence of two-dimensional photonic crystal line defect waveguides, which is larger than that of the conventional dielectric waveguides, is numerically investigated by finite-difference time-domain scheme and spatial Fourier transform method. The birefringence line waveguides are more suitable for polarization phase engineering than the bulk perfect photonic crystal structure because they provide low beam divergence and light transmission loss. The zeroth-order quarter- and half-wave plates based on the two-dimensional photonic crystal line waveguide have merits of high transmission efficiency and low interference with other components in photonic integrated circuits. Moreover, the designed zeroth-order wave plates have achromatic characteristic with high phase accuracy ( ±0.012π ) in a large frequency range (about 16 nm) around the telecommunication band (1550 nm). In addition, for realizing the relatively high order wave plates, the formed birefringence method is introduced in detail. The physical mechanism of formed birefringence is bringing path difference between two different polarizations. Based on the formed birefringence, the relative high-order (about 80th-order) WP is achieved by line-defect photonic crystal waveguides. The wave plates presented in this letter have many potential applications in future photonic integrated circuits such as integrated optical communications, polarization control and integrated depolarizing.

The applications of Electronic Dispersion Compensation (EDC) have recently attracted attention for high speed long haul transmission. Moreover, recent progress in signal formats has gained interest in recent years such as Differential Quadrature Phase Modulation (DQPSK). This format has higher spectral efficiency and reduced symbol rate compared to binary modulation compared to binary modulation formats. In this paper, we investigate the application of different EDC schemes with DQPSK format against chromatic dispersion (CD). The schemes are nonlinear feed-forward equalizer (FFE) and Decision-Feedback equalizer (DFE) and butterfly FFE-DFE. We demonstrate that butterfly structure can mitigates nonlinearity of cross-coupling because of processing two DPQSK tributaries independently. A 40 Gb/s simulated transmission system over 160km length is established. Simulation results show that butterfly FFE-DFE has better performance than separate FFE-DFE.

Free-Space Optics (FSO) can provide an effective line-of-sight and wireless communication with high bandwidth over a short distance. As a promising field of wireless communication, FSO is being accepted as an alternative of the more expensive fiber-optic based solutions. Despite the advantages of FSO, atmospheric turbulence has a significant impact on laser beam propagating through the channel in the atmosphere over a long distance. Turbulent eddies of various size and refractive index result in intensity scintillation and phase wander, which can severely impair the quality of FSO communication system. In this paper, a new geometrical model is used to assess the effects of turbulence on laser beam in its propagation path. The atmosphere is modeled along the transmission path filled with spatial-distributed spherical bubbles. The size and refractive index discontinuity of each bubble is K-distributed. This Monte Carlo technique allows us to estimate the fluctuation of intensity and phase shifts along the path. A pair of uncollimated rays arrives at the receiver through different path, and an optical path difference is produced. This difference causes a delay between the two rays. At the receiver, as the two rays are superposed, the delay ultimately affects the judgement of the bits. In the simulation, we assume that when the delay exceeds half of the bit width, bit error is possible. On the contrary, when the delay is less than the bit width, the bit error will not happen. Based on this assumption, we calculate the BER under different conditions, and results are further analyzed.

Using 0.8μm industrial CMOS technology, a 1×2 optical switch based on the carrier dispersion effect was fabricated. The device employed the conventional P-I-N structure with a typical 1μm-wide waveguide. The main process flow is presented in detail. The switching extinction ratio and the speed of the 1×2 switch are 21dB and 20ns, respectively. The fabrication repeatability is stable and reliable.

Optical filters with box-like response were designed and realized based on parallel-coupled double microrings in silicon-on-insulator. The properties of this design are simulated, considering the impact of the center-to-center distance of two rings, and coupling efficiency. Flat-top passband in the drop channel of the fabricated device was demonstrated with a 1dB bandwidth of 0.82nm, a 1dB/10dB bandwidth ratio of 0.51, an out of band rejection ratio of 14.6dB, as well as a free spectrum range of 13.6nm.

In this paper, we introduce our recent developments in the design techniques for high channel-count fiber Bragg gratings (FBG). Based on a double sampling method, we theoretically demonstrate a linearly chirped FBG with channels up to 153, which could be used as the dispersion compensator. Moreover, we propose a novel technique for the realization of a multi-channel notch filter by using a thermally-induced phase-shift of this kind of FBG. As an example, a multi-channel narrow band-pass filter is realized and successfully used to implement a multi-wavelength fiber laser.

White LED combining of blue chip and YAG:Ce phosphor suffers from a red spectral deficiency, resulting in a relatively low value of color rendering index (CRI). In our study, for an effort to improve color rendering properties of YAG:Ce phosphor-based white LEDs, highly luminescent red-orange emitting CdS/ZnS QDs were blended with YAG:Ce phosphors. Core/shell CdS/ZnS quantum dots with the emission wavelength of 618nm, was synthesized by thermal deposition using cadmium oxide and selenium as precursors in a hot lauric acid and hexadecylamine trioctylphosphine oxide hybrid. YAG:Ce phosphor was synthesized by high-temperature solid state reaction at 900-1200°C in a slightly reducing atmosphere for 4 hours. Blends of phosphors and QDs exhibited the prominent spectral evolution with an increasing content of QDs. A hybrid white LED, which combines a blue LED with the blend of YAG phosphor and QDs with a weight ratio of 1.5:1,was demonstrated with an improved CRI value of 86.

A high efficiency Silicon-on-Insulator (SOI) grating coupler between submicron waveguides and fibers was designed and fabricated. The experimental study showed that a maximum coupling efficiency of 38% and 3dB bandwidth of larger than 40 nm at each end of a waveguide is achievable in a fiber in- fiber out setup.

SOI promises a good platform for dense integration of optical devices. However, as dimensions scale down, propagation losses mainly caused by the scattering loss at sidewall had been serious problems. ICP etching of SOI is proved to be an available anisotropic etch technique to make submicron optical waveguide devices. With the help of e-beam lithography, We fabricated Single-mode submicron rib SOI waveguide with propagation loss as low as 1.2 dB/mm. Examples of SOI optical waveguide devices are also presented, such as sharp bends and ring resonators with a quality factor larger than 50,000.

An electro-optic modulator based on Mach-Zehnder interferometer and embedded PIN diode is demonstrated using silicon nanophotonic waveguide. Measurement results show that the device has high modulation efficiency with a V_πL figure of merit of 1.14 V·mm, high modulation depth of 96.27%, and large optical bandwidth from 1500 to 1600 nm. Transmission data rate up to 0.2 Gbps is demonstrated and the rise and fall time are 3.74 ns and 640 ps, respectively.

A detailed model of the diffraction of plane and Gaussian beams on plane uniform phase Bragg gratings based on Kogelnik's theory of coupled waves is presented. The model describes reflecting gratings with arbitrary orientation in a plane-parallel plate taking into account spectral width and angular divergence of diffracted beams. Extra formulas for angular and spectral selectivity are derived. The model results are compared with transmitting grating, the results show that the diffraction efficiency of reflecting volume Bragg gratings (VBGs) is higher than that of transmitting VBGs for beams with Gaussian spectral profile or angular divergence.

In this study, the amorphous Ba_0.7Sr_0.3TiO₃ (BST0.7) thin films were grown onto fused quartz and silicon substrates at low temperature by using a metal organic decomposition (MOD)-spin-coating procedure. The optical transmittance spectrum of amorphous BST0.7 thin films on fused quartz substrates has been recorded in the wavelength range 190~900 nm. The films were highly transparent for wavelengths longer than 330 nm; the transmission drops rapidly at 330 nm, and the cutoff wavelength occurs at about 260 nm. In addition, we also report the amorphous BST0.7 thin film groove-buried type waveguides with 90° bent structure fabricated on Si substrates with 1.65 μm thick SiO₂ thermal oxide layer. The design, fabrication and optical losses of amorphous BST0.7 optical waveguides were presented. The amorphous BST0.7 thin films were grown onto the SiO₂/Si substrates by using a metal organic decomposition (MOD)-spin-coating procedure. The optical propagation losses were about 12.8 and 9.4 dB/cm respectively for the 5 and 10 μm wide waveguides at the wavelength of 632.8 nm. The 90° bent structures with a small curvature of micrometers were designed on the basis of a double corner mirror structure. The bend losses were about 1.2 and 0.9 dB respectively for 5 and 10 μm wide waveguides at the wavelength of 632.8 nm. It is expected for amorphous BST0.7 thin films to be used not only in the passive optical interconnection in monolithic OEICs but also in active waveguide devices on the Si chip.

BaTiO₃ ferroelectric films were prepared on Si(111) substrate by sol-gel method with glacial acetic acid as solvent, and acetylacetone as stabilizer, barium acetate and tetrabutyl titanate as precursor. The photoluminescence of BaTiO₃ ferroelectric films were studied. Intense photoluminescence of amorphous BaTiO₃ ferroelectric films excited by blue light was observed at room temperature (RT). The emission band is in a range of 540nm to 660nm in wavelength. The ferroelectric films annealed (at 673K for 8 hours) had the best photoluminescence property, when the films excited by 450nm line, the peak width is about 30nm from 580nm to 610nm, towards the yellow region. Moreover, the photoluminescence of BaTiO₃ ferroelectric film is stable. The emitting region, peak wavelengths and width are not dependent on excitation wavelength and/or film thickness. The luminescence intensity increases with film thickness increasing, but decreases with the excitation wavelength raising. The crystalline BT ferroelectric films had no properties above.

Electronically controlled phased-array antennas can adaptively scan radiated beams in three-dimensional space without mechanically moving parts. While most of the research on phased-array antennas has been focusing on broadband beam steering less attention has been devoted to null steering. Broadband null steering requires a beamformer that can generate variable and frequency independent true time-delays (TTD). In this paper we propose and demonstrate the concept of an Opto-VLSI-based tunable true-time delay generation unit for adaptive null steering in phased array antennas, where arbitrary single or multiple true-time delays can simultaneously be synthesized. Simulated azimuth gain patterns for a 4- element antenna arrays is presented, and experimental results are shown, which demonstrate the principle of the proposed true-time delay unit.

Radio frequency (RF) signal processors based on photonics have several advantages, such as broadband capability, immunity to electromagnetic interference, flexibility, and light weight in comparison to all-electronics RF filters. It still requires innovative research and development to achieve high-resolution reconfigurable photonic RF signal processors featuring high selectivity, resolution, wide tunability, and fast reconfigurability. In this paper, we propose and experimentally demonstrate the concept of a reconfigurable photonic RF filter structure integrating an Amplified Spontaneous Emission (ASE) source, an Opto-VLSI processor that generates arbitrary phase-only steering and multicasting holograms for wavelength selection and attenuation, arrayed waveguide gratings (AWGs) for waveband multiplexing and demultiplexing, high-dispersion fibres for RF delay synthesis, and a balanced photodetector for generating positive and negative processor weights. Independent control of the weights of a reconfigurable photonic RF filter is experimentally demonstrated.

In this paper, we propose and experimentally demonstrate the principle of a novel reconfigurable optical add-drop multiplexer (ROADM) structure employing an Opto-VLSI processor. The ROADM structure integrates two arrayed waveguide gratings for wavelength division multiplexing and demultiplexing, a 4-f imaging system comprising a fiber array, an imaging lens array and a reflective Opto-VLSI processor. The Opto-VLSI processor is driven by phase holograms to switch the various wavelength channels between the fiber ports to achieve "through" or "drop" operations. Phase hologram optimization is investigated, for maximising the number of wavelength channels while keeping adequate insertion loss and crosstalk levels. Experimental results are shown, which demonstrate the principle of the ROADM with crosstalk of less than -30dB and insertion loss of less than 6dB for the drop and through operation modes.

A new procedure for fabricating a periodic structure on a UV polymer at submicron range using holographic interferometry and molding processes is described. First, holographic interference using a He-Cd (325 nm) laser was used to create the master of the periodic line structure on an i-line sub-micron positive photoresist film. A 200 nm nickel thin film was then sputtered onto the positive photoresist. Final line pattern on a UV polymer was formed from casting against the master mold. Initial results show the technique can accurately control the grating's period and depth. A high aspect ratio of grating period (gp) to depth (d) is about 1.35.

The propagation of polarized optical pulses in a birefringent nonlinear waveguide has been studied by nonlinear coupled equations which is presented in a new normalized format. It is found that the polarization coupling features of two orthogonally polarized components of the optical pulses are determined by a dimensionless parameter: the ratio of the dispersion length to the intrinsic beat length, L_D/L_B. When πL_D/L_B 1, the pulse has the same coupling features as the continuous wave, only the energy of the peak part of the pulse can couple forth and back between the two orthogonally polarized components. When 1 > πL_D/L_B, the perpendicularly polarized component of the pulse, i.e. instable mode, can efficiently couple to the parallel polarized component, i.e. stable mode. When πL_D/L_B lies in the rest region, the pulse will be significantly compressed and break into multi-peak pulses. The peaks of the pulse show different propagation speeds, thereafter the separation of the peaks increases while the pulse propagates.

There are many preparation methods of porous silicon(PS), such as electrochemical etching(ECE), photochemical etching, chemical etching and so on. ECE, also known as anodic etching, is more common among these methods. A lot of holes are given priority to be etched on the surface of silicon. The top and vertical aspects of the holes are easily etched while horizontal aspects wall of the holes are quiet different, and then tree-like or sponge-like porous structure is formed. In this paper, we obtained porous structure on the surface of silicon using lithography and dry etching method. The diameter of the hole was 2μm or 6μm. The etching depth of the samples was about 70nm, 140nm and 260nm. Photoluminescence (PL) phenomenon was observed by using light of 270nm, 280nm, 330nm, 455nm and 460nm wavelength to excite the samples. The results showed that PL intensity was the best when excitation wavelength was 270nm or 280nm, compared with 330nm, 455nm and 460nm. From PL analysis of all samples, It exists three emission peaks about at 372nm, 425nm and 473nm. When the diameter of the PS was the same, it was found that PS with etching depth at 140nm was more efficient. It means that PL intensity of the was better than other samples when the etching depth was 140nm. Likewise, samples of which the diameter was 2μm has much better PL than that of the other samples.

High efficiency coupling from fiber to slot and strip waveguides using a double-tip coupler is presented. The double tips are inverse tapered, while their distance is decreased. The coupling efficiency reaches 90.9% with a taper length of only 30μm for coupling fiber to slot waveguides. With a mode transformer, the slot waveguide mode can be converted to strip waveguide mode with an efficiency of 99.3% in a length of 15μm. The impact of several parameters, such as distance between tips, taper length, and tip-end width, are simulated and optimized to improve the coupling efficiency.

Samples of various of various concentrations are prepared and kept unsintered for a period of three years to study the consistency of composition prepared and structural evolution of glass. The expanded peaks in the Raman Spectra arise due to thermal agitation and a Boltzman type of distribution is expected in the silicate gels. The behavior of the gels during the dehydroxylation and dehydration is conditioned by its microstructure which depend upon the physical conditions i.e. pH, drying conditions.

Copper (Cu) interconnect has been used for communication systems at shorter length scales for both latency and bandwidth sensitive applications. However, as the computational bandwidth of the integrated circuits increases dramatically, Cu interconnect at short distances especially in bandwidth sensitive applications is struggling to keep up. This presents a good opportunity for optical interconnect to penetrate the short distance world. This paper reviews the latest advances of optical interconnect for off-chip high bandwidth communications. The focus will be on the materials and processing aspects for realizing optical interconnects through low cost and manufacturable approaches, especially on various novel schemes to achieve passive optical alignment between optical device and waveguide, and on novel package architectures to achieve high bandwidth using the optical interconnects.

A 1550 InGaAsP-InP multiple-quantum-well (MQW) transistor laser is numerically modeled. The proposed structure has a deep-ridge waveguide and asymmetric doping profile in the base (i.e. only the part below QWs of the base is doped) which provides good optical and electrical confinement and effectively reduces the lateral leakage current and optical absorption. The important physical models and parameters are discussed and validated by modeling a conventional ridge-waveguide laser diode and comparing the results with the experiment. The simulation results of the transistor laser demonstrate a low threshold (< 10 mA) and a > 25 % slope efficiency with the current gain of 2 ~ 4. The optical saturation and voltage-controlled operation are also demonstrated.

We proposed and theoretically simulated an optically switchable and tunable ultrawideband monocycle generator based on wavelength conversion in a semiconductor optical amplifier (SOA), and optical tunable delay in an optical delay line (ODL). The system is optically switchable in pulse polarity, and tunable in both pulsewidth and radio frequency (RF) spectrum.

SOI based waveguide devices are becoming more and more active. The main results of the devices investigated in our team are presented in the paper. Photonic crystal with sharp bends was made and its excess loss is 1.1±0.4dB per mirror. Two kinds of couplers, slot coupler and grating coupler, were successfully fabricated. Coupling loss of the slot coupler is < 3dB between sub-micron optical waveguides and micronscale optical fibers. A coupling efficiency of 40.7% and 3-dB bandwidth of > 40nm of the grating coupler are obtained. Microring and microdisk resonators were simulated and optimized. Their Q factors and extinction ratios are 5.3×104, 14dB, and 2.8×105, 10dB, respectively. SOI PIN diode electro-optical switches with microring, microdisk and MZI were developed. Rise and fall time is 0.37 ns and 2.57 ns, respectively, for a microdisk optical switch.

Spectrum analysis technique is introduced to measure the time delay of the silicon-on-insulator (SOI) micro-ring slow light device. The interference spectra of the TE and the TM polarization are obtained based on dual-quadrature spectral interferometry technique. By analyzing the observed spectral interference, the phase and time delay of the output optical pulse of SOI micro-ring is estimated. This method has a very high accuracy of time measurement because it avoids the impact of response speed of optoelectronic device, and moreover, it provides a complete measurement of the complex electric field as a continuous function of frequency.

Pushbroom Hyperspectral Imager (PHI) is a new intensively researched subject in the spectral imaging field. Hyperspectral imaging is getting wide attention due to their high spectral resolution. The conventional imaging spectrometer uses prism and grating as dispersive component. As the Fabry-Perot (F-P) cavity has high resolution and excellent frequency selectivity, in this paper, MEMS F-P array filter is used as the light splitting device. It is compact, fast modulate rate, high precise and easy to be integrated. In this paper, the optical property of the integrated micro F-P cavity tunable filter has been studied. Optical thin film design software TFCalc has been adopted to design the optical thin film of the micro filter. Design and analysis of antireflection coatings, high reflection and the F-P cavity interference filter. The test results show that the optical properties of the fabricated samples are consistent with the design results. In order to simulate the working mechanism of the micro F-P cavity, two filters were fixed together to form an F-P cavity. The filter effect of the F-P cavity was tested using a spectrometer, the comb filter pattern was observed. The feasibility of the optical F-P cavity tunable filter is confirmed.

We study numerically the focusing effects when a Gaussian beam pass through a two-dimensional photonic crystal consisting of triangular structure of air holes. By using plane wave expansion (PWE) and finite difference time domain (FDTD) methods, we find the width of convergent beam is about 2μm. Meanwhile, the focusing effects also are influenced by the Gaussian half-width, the numbers of the layers and the incident angle. The structure can be used for light-coupling and near-field scan image application.

Coating material has been considered as being made up of a lot of small tablets. These tablets have plane surface during the whole film preparation process. Based on the assumption that a column etching pit will form in coating material when electron beam is used for heating, influences of the etching pit's dimension and the internal structure of the vacuum chamber on films thickness uniformity have been investigated. Results reflect that the appearance of etching pit does not always cause negative influence on films thickness uniformity. The negative impact of etching on films thickness uniformity can be reduced by optimizing the internal structure of the vacuum chamber and preparation technical parameters. But, it is difficult to achieve the beneficial action. This investigation is useful to help us understand physical meaning of the emission characteristics of the evaporation particle and design experimental scheme.

Quantum dots have many applications in optoelectronic device such as LEDs for its many superior properties resulting from the three-dimensional confinement effect of its carrier. In this paper, single chip white light-emitting diodes (WLEDs) were fabricated by combining blue InGaN chip with luminescent colloidal quantum dots (QDs). Two kinds of QDs of core/shell CdSe /ZnS and core/shell/shell CdSe /ZnS /CdS nanocrystals were synthesized by thermal deposition using cadmium oxide and selenium as precursors in a hot lauric acid and hexadecylamine trioctylphosphine oxide hybrid. This two kinds of QDs exhibited high photoluminescence efficiency with a quantum yield more than 41%, and size-tunable emission wavelengths from 500 to 620 nm. The QDs LED mainly consists of flip luminescent InGaN chip, glass ceramic protective coating, glisten cup, QDs using as the photoluminescence material, pyroceram, gold line, electric layer, dielectric layer, silicon gel and bottom layer for welding. The WLEDs had the CIE coordinates of (0.319, 0.32). The InGaN chip white-light-emitting diodes with quantum dots as the emitting layer are potentially useful in illumination and display applications.

We propose and theoretically demonstrate multi-channel all-optical non-return-to-zero (NRZ) format to return-to-zero (RZ) format conversions for wavelength division multiplexing (WDM) network. By using two fiber based delay interferometers (DIs) with free spectral range (FSR) of 20GHz and 40GHz, 8*10Gb/s (200GHz spacing on ITU grid) RZ signals can be converted to corresponding NRZ signals with small penalty. The principle and simulation are analyzed in both time and frequency domains. Format conversions are demonstrated for multi-channel RZ signals with duty cycle of 33%, 50% and 66% respectively. Q factors before and after the multi-channel RZ-to-NRZ conversions show a good performance and thus the practicability of the proposed format converter.

A novel microwave photonic notch filter structure is proposed and experimentally demonstrated. The structure is based on a recirculating delay line loop consisting of an optical variable delay line, a semiconductor optical amplifier (SOA) and a tunable narrowband optical filter. Negative tap is generated using wavelength conversion based on cross-gain modulation of amplified spontaneous emission spectrum of the SOA. A narrow bandpass response with negative coefficients and a broadband all-pass response are combined to achieve a narrow notch response with flat passband which can eliminate interference with minimal impact on the expected signal. Experimental results show good agreement with theoretical analysis.

We present a multiwavelength mode-locked fiber ring laser incorporating a semiconductor optical amplifier (SOA) and a Fabry-Perot semiconductor optical amplifier (FP-SOA). SOA is mode-locked by an injected external optical signal, act as loss modulator, and FP-SOA serves as a tunable comb filter. Our laser source can generate 19 synchronized wavelength channels with the extinction ratio of about 21 dB, each mode-locked at 10 GHz, and modelocked pulse width is about 40 ps. Oscillation wavelengths band and wavelength spacing can be tuned by adjusting bias current and a tunable optical delay line (ODL) or a temperature controller, respectively. Polarization insensitive devices ensure that the output power is rather stable.

the splitting properties of the polarization beam splitter (PBS) have been numerically studied using the finite difference time domain method. Based on the analysis of relationship between the self-collimating transmission frequency and radius of air hole for two-dimensional square lattice in photonic crystals, a self-collimating polarization beam splitter is designed. Low-loss transmission, wide angle bending and high splitting ratio can be realized in this structure.