This PDF file contains the front matter associated with SPIE Proceedings Volume 10849, including the Title Page, Copyright information, Table of Contents, Author and Conference Committee lists.

In this paper, we report a unique monolithic integrated arrayed-waveguide grating that can act as both multiplexer and demultiplexer with an all-metal rod for compensating. There are almost the same inspectrum profiles observed either the original chip or the athermalization one. A Flat-top athermal AWG modules of 100-GHz×40-ch are fabricated in this way. While changing the temperature from -40 to 85°C, the center wavelength shift is within ±25pm and the insert loss change is less than ±0.14dB.

A free space quantum communication multi-dimensional modulation system based on pulse position modulation and polarization encoding is put forward and designed and is used to send quantum information and classical information simultaneously. Atmospheric channel model and coexistence system model is built. We perform a simulation experiment for transmitting signal in atmospheric, using Optisystem and Matlab together. The binary sequence before modulation and that after demodulation are compared and analyzed. The error bit rate, eye diagram and quality factor of classical optical date are obtained. Stabilities of classical optical signal during the transmission are tested. The results show that this multi-dimensional modulation system can decrease the numbers of information channels needed and reduce the demands for power load and systematic complexity in communication terminals. The proposed quantum communication system is confirmed to be effective and applicable.

We numerically and experimentally demonstrate an all fiber parametric frequency combs generator with only one continuous-wave (CW) laser. The light from the laser is launched into a section of fiber to stimulate Brillouin scattering. The scattered Stokes wave and the transmitted wave are used as two seeds to pump parametric process in a highly nonlinear fiber (HNLF). The generated comb lines with a spacing equal to a Brillouin frequency shift of the fiber. To further improve the experimental results, the length of single mode fiber (SMF) used for pulse compression is optimized by numerical simulation. The results show that with a 100-m SMF, a 38-tone frequency comb spaced at 10.67GHz with a 10dB power variation can be obtained.

We propose to compare the hardware cost of OTN switching and IP switching to obtain the ballpark adaptation range for the two switching mode. By abstracting the switching behavior of OTN switching equipment and IP router, we present a detailed study on the hardware cost in the case of ensuring connectivity. A unified network-level connection model is established based on CLOS switching network, and then we compare hardware costs for IP switching and OTN switching. The hardware cost of the two switching mode in different L1 switching granularity and different port rate cases is simulated. Simulation results show that OTN switching has lower hardware cost than IP switching when average bandwidth for traffic demand excess 250Mbps in the cases of ODU₀ switching granularity.

A photonic approach for RF self-interference cancellation based on phase modulation wavelength selective filtering is proposed. This scheme is quite compact and simple and free of auto-bias drift control unit. This scheme provides a potential solution to RF cancellation and full-duplex transmission for 5G wireless communications. The proposed RF SIC method is applicable for the WiMax (IEEE 802.16) wireless service and other high frequency bands.

The acousto-optic tunable filter (AOTF)-based spectrometer has been widely used in hyperspectral imaging applications. The sidelobe phenomenon which is the result of sinc2 shape of the spectral response reduces the quality of the spectral data critically. Especially when a laser appears in the scene, the image point of the laser will be present in images of several bands with varying positions and intensity. This paper discussed the sidelobe phenomenon using the phase mismatching theory and proposed a sidelobe model based on the three-surface AOTF model(TSAM) which was a previous related work. This model provided a simplified method to trace laser light in the AOTF imaging system. A verification experiment was demonstrated, in which a dual-channel AOTF imaging system was introduced. The laser pixel coordinate and DN value were extracted from the panchromatic image and were put into the proposed model, which gave the predicted positions and DN values in different bands. The measured values were extracted from the spectral images. Results showed that the predicted values were in g

A system for detecting leakage of water pipeline is built based on the Raman distributed optical fiber sensing technique. Feasibility of the system is experimentally studied and a program for automatical alarm is developed. The results demonstrate that when the leakage of water causes a temperature variation no less than 1°C relative to the surrounding, the distributed optical fiber sensors are able to detect and locate the leakage. To some extent the water leakage spreading range can be shown, and when there are two or more leaks spaced by no less than 1m, the system can successfully identify the number of leaks.

In this paper, two 2×2 Mach-Zehnder thermo-optic switches with and without two deep air trenches on both sides of the active arm are designed and fabricated on silicon-on-insulator(SOI) wafer. The experimental results show that switching powers of the two switches with and without trenches are 22.33 mW and 28.44 mW respectively when operated at 1560 nm wavelength. That is to say, the switching power of thermo-optic switch is reduced by 21.5 % due to the trenches. Moreover, the extinction ratios of the cross state are both over 32 dB.

The phase-generated-carrier (PGC) algorithm is the most widely used signal demodulation method for fiber-optic interferometer sensors (FOIS), due to its distinct advantages of high resolution, wide dynamic range, good linearity and multi-channels demodulation capability. Even though significant progress has been made in PGC algorithm, the influence of phase modulation amplitude variation for PGC-differential-cross-multiplying approach (PGC-DCM) and PGC-Arctangent approach (PGC-Arc) still remains, especially on large-scale FOIS array. In this paper, a novel ameliorated digital PGC algorithm based on three-channel mixing signals has been present to mitigate this effect, which called PGC-differential-cross-dividing approach (PGC-DCD). The most distinguishing feature of this method is that it directly picks up the phase modulation amplitude from the interference signal by series of mathematical calculation and synchronically used in subsequent demodulation processing. So, the variation of phase modulation amplitude, induced by the internal or external disturbances, can be directly detected and synchronically updated in demodulation. The theoretical derivation and simulation experiment show that this approach is robust to the variation of phase modulation amplitude, and is a potential demodulation algorithm for FOIS, especially for large-scale FOIS array.

Based on the principle of phi-sensitive optical time domain reflectometry (φ-OTDR), the distributed optical fiber acoustic sensing (DAS) system can detect long distance and real-time acoustic signal by demodulating the phase change of backward Rayleigh scattering in the single mode fiber. Low sensitivity of single-mode fiber limits the underwater acoustic signal detection. In this paper, we design an elastic sensitizing layer base element encapsulation structure, and establish a theoretical analysis model. The theoretical analysis and experiment are carried out, the sensitivity of the acoustic pressure sensitivity of the elastic sensitizing layer structure is -141.6dB re 1rad/μPa, which is in good agreement with the theory.

A simplified approximate theoretical model between phase noise and Rayleigh backscattering (RS) light is introduced to analyze the performance of distributed acoustic sensing, and results show that noise is relative to the static RS amplitude. Er³⁺-doped active fiber is used to increase RS light and compress system noise. The system phase noise reduces more than 14 dB, a noise level of 9×10^-4 rad/√Hz and signal-to-noise ratio of 46.6 dB @ 100 Hz are obtained experimentally.

Based on phase-sensitive optical time domain reflectometer (φ-OTDR) and phase-generated carrier (PGC) algorithm, a real-time DAS system is built. The maximum sensing length and spatial resolution of the DAS system are 10 km and 6m, respectively. A field test of the DAS system using a single-mode telecommunication fiber cable with a length of 430 m for surface seismic measurement is presented. In the test, a series of conventional 3C-geophones are utilized as a criterion for comparison. Through the raw data absence of processing, preliminary wave, consistent with geophones, are clearly described, which means that the DAS system is capable of surface seismic detection.

Distributed acoustic sensing system can be used in the long-distance and strong-EMI condition for monitoring and inspection. In this paper, location method for optical fiber multiple dynamic disturbances signals is proposed to solve the difficulty with Distributed acoustic sensing (DAS) system in effectively locates multiple dynamic disturbances. The first step: locate multiple dynamic disturbances signals exactly by using the multiple threshold method. The second step: the Empirical Mode Decomposition(EMD) method and the Fourier transform(FFT) is proposed to extract the signal features . By analyzing the time domain signals of the intrusion location that we can look for the most efficient signal feature to form a pattern feature vectors for classification. After the first two steps, we can get feature vectors of different types of dynamic disturbances. By utilizing support vector machine(SVM) classifiers to identify feature vectors, patterns of intrusion events are recognized accurately. Experiments show that after using this method to process 300 dynamic disturbances samples generated by three different intrusion events, namely, passing, hurling and knocking, the location accuracy is about 1.6m, the recognition rates of intrusion events are over 90%.

In a pipeline monitoring system, the engines of machines passing by can lead to vibration excitation for the optical fiber. The signal generated by the vehicle driving is similar to the excavation disturbance signal. Therefore, it may generate incorrect classification for one dimensional signal recognition by the pre-warning system. An image - based signal processing method was built to solve these problems. Firstly, completing differential operation for all detection points in the whole detection range, and dividing the differential data basing on the threshold value. Then extracting the event areas based on the method of the image introduced in this paper. Finally, utilizing the Hough transform to extract the existing line segments, and analyzing the slopes to determine the type of events. This method can effectively eliminate noise interference and reduce misinformation and omission alarm at the same time. This research will ultimately provide the basis for judging the output of alarm events in distributed optical fiber vibration sensing system.

Atomic sensing devices usually contain fiber coupling systems. A two-mirror fiber coupling system is usually used in our research to couple spatial light into polarization maintaining fiber. In order to improve the axes alignment accuracy and optical extinction ratio of this fiber coupling system for atomic sensing devices, we propose an improved method based on the influence of mirrors on beam polarization. The polarization maintaining fiber can maintain the polarization of linear polarized light only when the polarization direction coincides with the fiber. However, according to theoretical analysis by Jones Matrix and experimental results, we demonstrate that mirrors have non-negligible influence on beam polarization, which causes difficulty in axes alignment. Both dielectrical mirrors and metallic mirrors have influence on the azimuth and ellipticity of polarized light, and the influence of dielectrical mirrors is more remarkable than that of metallic mirrors. Thus we propose to add a half wave plate or a quarter wave plate in the system to compensate for the influence of mirrors, and the extinction ratio of fiber output light is consequently increased. According to the experimental results, our new approach can increase the extinction ratio by about 30dB.

In this paper, a tunable dual-bandpass microwave photonic filter (MPF) based on a single broadband light source (BBS) has been proposed and experimentally demonstrated. By cascading two chirped fiber Bragg gratings (CFBG) with different reflection bandwidth and chirp parameter, the different delay of the modulated light signal in the system is introduced and consequently, a MPF with two different passbands can be realized. Two different passbands with the frequency of 6.75 GHz and 16.01 GHz is obtained in the experiment. By changing the free spectral range (FSR) of the Mach Zehnder interferometer (MZI) through an optical tunable delay line (OTDL), the central frequency of the two passbands can be changed. The dual-bandpass MPF presented in this paper is easy to implement and has good tunability and stability.

In general, conventional resistance strain balances are used to obtain aerodynamics forces in hypersonic wind tunnels. Owing to the advantages of fast response, high sensitivity and anti-electromagnetic interference, fiber optic sensors provide a new technical approach to wind tunnel strain balance. In this paper, a three-component fiber optic balance based on MEMS Fabry-Perot strain sensor has been developed. The MEMS strain sensor based on Fabry-Perot interference was fabricated by surface and bulk MEMS techniques. The MEMS FP strain sensor has a high finesse factor by adapting high-reflection films deposited on the surfaces of FP cavity. The three-component fiber optic balance has been calibrated, and evaluated in a hypersonic low density wind tunnel. The results of static calibration and wind tunnel tests have declared a good performance compared to the results of resistance strain balance.

Due to the military and commercial demands, space activities have become more frequent, and the exploration of the space around the world has been accelerating. The demand for high-speed data communications has prompted the development of satellite laser communication technology. Satellite laser communication has the advantages of large communication capacity, low transmitting power, long transmission distance, strong anti-electromagnetic interference capability and high security, which makes it gradually become an important direction for the development of space backbone network. Satellite laser communications terminals continue to become miniaturized volume, light weight and low power consumption, which makes it possible for small satellites applying laser communications technology. This paper introduces the development history and latest research progress of satellite laser communication in foreign countries, and the development status of domestic satellite laser communication, and summarizes some inspirations for the development of satellite laser communication technology.

In this paper, we proposed a new approach to measured humidity by polymer-coated micro-nano Bragg grating. The FBG was written in a 21.85-μm –diameter micro-nano fiber by 244-nm UV laser. Humidity changed the force that acting on the micro-nano fiber, thus the bandwidth of the reflection spectra was introduced and humidity measurement was therefore realized. When the humidity increased, the linearity value was 99 % and the bandwidth changed 0.00312 nm/%. The linearity is 97% and 98% in the stages of humidity reduction in 90 to 65 %RH and 65 to 30 %RH, respectively.

An all-fiber microstructure Mach–Zehnder/Michelson interferometer (MZI/MI) fabricated from dual-mode elliptical multilayer-core fibers (EMCFs) is proposed and experimentally characterized. The index profile of the EMCF is particularly designed to support a distinct dual-mode operation, LP₀₁ and LP₁₁^even modes, with approximately equal excitation coefficients. Thus, the detected interference patterns, rather clean due to the few-mode property, shift as the environmental parameters due to strong interaction between high-order modes and measurands through evanescent waves. The MZI/MI has potential for improving the surrounding refractive indexes (SRI), axial micro-strain and liquid-level measurement resolutions. Both the propagation characteristics and operation principle of such a sensor are demonstrated in detail. A sensitivity of ~213 nm per refractive index unit (RIU) within the SRI range of 1.333–1.373, ~4.98 pm/μɛ within the axial strain range of 0-800 μɛ and ~32 pm/mm within the liquid-level range of 0-35mm are obtained through simulation, respectively.

A 3-section deep etched Q-modulated slotted Fabry-Perot laser (QMSFP) composed of a modulator, a gain section and a filter is designed and simulated with transfer matrix method and traveling wave method and finally experimentally demonstrated in this paper. This QMSFP has been fabricated in 1550 nm InGaAsP/InP-MQW wafer with Quantum Well Intermixing (QWI) technology. The static measurement results show that an extinction ratio (ER) of 13.6 dB can be achieved with the modulator length of 66.4 μm and the reverse bias of 0 V and 6.5 V at specific injection current in the gain section and filter section. The lasing threshold current difference between ON and OFF states can approach 10 mA under fixed current of the filter section. The Side Mode Suppression Ratio (SMSR) of the ON state is >34 dB with the measured output power from the front face >149 μW. There is no mode-hop between ON and OFF state. The dynamic simulation results under high speed modulation will also be presented.

This paper presents a kind of highly nonlinear fiber (HNLF) sensor for distributed monitoring. In order to realize the high performance of the stimulated Brillouin scattering (SBS) in HNLF, the experiments diagram based on the topological structure of Brillouin optical time domain analysis (BOTDA) is optimized through two-stage modulation by two electro optical modulators (EOMs) to realize high extinction ratio. The SBS characteristics of the HNLF have been studied, including the Brillouin gain bandwidth, Brillouin gain center frequency and SBS threshold. It is found that the HNLF has a wider Brillouin gain bandwidth. The SBS threshold of HNLF is larger than that of single mode fiber, which are 78 mW and 7.9 mW respectively. The larger SBS threshold is useful to avoid SBS in some situations that Spontaneous Brillouin Scattering is necessary. Based on the Brillouin gain center frequency, the Brillouin frequency shift coefficients of strain and temperature in HNLF have been studied, which are 0.0308 MHz/με and 0.413 MHz/ °C respectively.

The scale factor and other performance of high-precision fiber optical gyro(FOG) is directly related to the performance of the gyroscope using the Fiber source. High-precision fiber optic gyroscope with wide spectrum fiber source used to output spectral width and high power and get high mean wavelength stability. because the fiber gyro scale factor is calibrated by mean wavelength, the mean wavelength stability directly determines the stability of the scale factor of FOG, which is the mean wavelength stability that is the most important parameter in high precision fiber optic gyroscope with wide spectrum source. For erbium doped super-fluorescent fiber light source, the change of average wavelength is mainly due to the change of ambient temperature.

In this paper, based on the theory and concept of photonic crystal, an erbium doped photonic crystal fiber light source based on a double backwards structure is constructed, and the optical path and circuit driving scheme of the erbium doped photonic crystal fiber light source are designed. By optimizing the parameters of erbium-doped photonic crystal fiber, including the length of the erbium-doped photonic crystal fiber, the power loss and pumping power and so on, we finally get the prototype of the erbium doped photonic crystal fiber source. Through the experiment of the light source, the wavelength and the temperature correlation coefficient of the fiber light source reach 1ppm/ degrees.

For the current multi-optical sensor cross-communications algorithm, the main method is the centralized algorithm. However, this algorithm has the characteristics of complex calculation, low effectiveness. Different types of optical sensors detect the target multi-layer attributes, and based on a predetermined priority sequence, they are finally judged by the global data fusion system, and the level of the target is divided. The target response level function is established by fuzzy algorithm to improve the communication efficiency of the sensor network. Based on the established target response level function, this paper proposes a multi-optical sensor cross-communication algorithm based on auction algorithm. The auction algorithm belongs to a distributed algorithm, and simulation experiments show that the auction algorithm proposed comparing with the centralized algorithm, the auction algorithm has the characteristics of small communication network demand, fast calculation speed, and good convergence and stability of the algorithm.

Narrowband Internet of Things (NB-IoT) is a new radio access technology, in 3GPP, NB-IoT has been introduced to support the Internet of Things. This paper summarizes the application of NB-IoT in the wireless sensor network, and describes how NB-IoT can solve the problem of Internet of things, including deployment, battery life, equipment complexity and other common problems. Considering that stand-alone as a dedicated carrier can cover wider range, does not conflict with the existing system, and has low power consumption, it’s very suitable for smoke alarm which care more about wide coverage, low power requirements. This article presents a detailed model that describes how to use NB-IoT can make smoke alarm working in the power saving mode (PSM) and how to setup parameters in this mode. This paper also shared some requirements of GA1151-2014 General requirements for wireless communication function of fire alarm system, and pointed out the requirement of smoke alarm to NB-IoT.

In recent years, more attention has been paid to FSO(free space optical) communication system for the advantages of high security, easy installation and deployment and high transmission data compare to conventional frequency wireless communication. FSO communication has a wider prospect in application of civilian and military. However, the FSO link is easily affected by the atmospheric effects such as cloud, rain, fog and so on, which leads to the decline of the performance of the communication system. Orthogonal frequency division multiplexing (OFDM) is a kind of multicarrier transmission in which high data rate streams are split into lower rate streams and then transmitted simultaneously over several narrow-band subcarriers. OFDM subcarrier can use many different modulation modes. One of the main modulation modes is multilevel quadrature amplitude modulation (MQAM). OFDM is known for its increased robustness against frequency selective fading, narrow-band interference, and high channel efficiency and it is widely used in broadband wireless communication systems. Meanwhile, most of the current studies about free space optical communication are based on atmospheric turbulence models with lognormal, Gamma-Gamma and M distribution. There are not appropriate for aperture averaging reception condition. In 2012, Barrios R and Dios F proposed a new Exponentiated Weibull atmospheric turbulence model for the first time. Exponentiated Weibull atmospheric turbulence model is suitable for the weak to strong turbulence and the average diameter of the aperture. Therefore, this paper aimed at the combined effects of the Exponentiated Weibull atmosphere turbulence, geometric spread and pointing errors on airborne FSO communication system, the bit error rate (BER) performance of the OFDM airborne FSO communication link is investigated. The OFDM optical communication link model based on M-QAM is built, and the electrical carrier to noise ratio for OFDM optical communication link is obtained. The closed form mathematical expression for the total average BER performance is theoretically derived. The relationship between the BER performance and the transmitted optical power under different parameters such as the atmosphere turbulence, the normalized jitter standard deviation and the normalized beam-width is analyzed by simulation. The simulation results show that with transmission optical power increased, the performance of optical link which only under the influence of atmospheric turbulence is better improved than which combined effect of atmospheric turbulence and pointing error. The pointing error has a obvious deterioration in the performance of the system. The performance of the bit error rate improved by increasing the transmission optical power when not considered pointing error is 3 orders of magnitude higher than when considered pointing error. The bit error rate increases with the increase of turbulence intensity, the normalized jitter standard deviation and the normalized beam-width. The airborne system performance is similarly improved in different modulation orders by increasing the transmitted optical power. The BER performance is obviously improved by increasing the transmitted optical power when the normalized jitter standard deviation is less than 0.7. In practical application, the derived average error rate closed expression can be used to estimate the performance of the system and provide reference for the design of the airborne FSO communication system.

Microwave photonics (MWP) is an interdisciplinary topic that studies the interaction between microwave and optical signals, for different applications such as photonic microwave waveform, phased-array antennas (PAAs), broadband radio-frequency (RF) channelization, and optical-wireless access networks (OWANs). In this paper, we focus on two aspects: part recent progresses of MWP and its optical wireless system applications in OWANs. Based on the reported works, a brief overview of research progress in MWP is then presented. In addition, the low-loss and wide bandwidth advantages of MWP make it attractive for the transmission and processing of signals, while the development of highcapacity optical wireless access systems has required the use of MWP techniques in optical transmitters and receivers. These have led to the development of the research issues of MWP. Therefore, we summarize and discuss some recent progresses of MWP and its featured applications in OWANs. And an overview about our works on MWP and its applications is also presented. Finally, the trends in technology development and key issues of MWP are indicated.

In this paper, a sensor for simultaneous measurement of seawater temperature and depth using polarization-maintaining fiber Bragg grating (PM-FBG) and extrinsic Fabry-Perot interferometer (EFPI) is presented. The PM-FBG and the EFPI are cascaded into the sensor. Epoxy resin is used to increase the temperature sensitivity of PM-FBG while an aluminum sleeve is used to reduce the pressure sensitivity of PM-FBG. And the EFPI is formed by the pigtail of the PM-FBG and the stainless steel diaphragm at the end of the aluminum sleeve. The new sensor design, fabrication, packaging, and measurement are addressed. The performance of the sensor for the concurrent measurement of pressure and temperature is investigated by analyzing the experimental data, and the characteristic curves for the measurement of the sensor are presented. Experimental results show that the temperature sensitivity is about 25.18 pm/°C (left peak) and 24.69 pm/°C (right peak) and the pressure sensitivity is about 35.78 um/MPa.

Nonlinearity in few-mode fiber (FMF) communication is investigated. Numerical systems with six-mode fiber links are simulated to analyze the impacts of modal dispersion and mode-dependent loss on nonlinear propagation in FMF.

Plastic optical fiber (POF) probe with macro-bending (U-shaped) biconical tapered structure is proposed and optimized for the relative humidity (RH) sensing in this paper. And the probe was coated with a fluorescent moisture-sensitive film containing rhodamine 6G (R6G). Its sensing performance was optimized by changing the probe's curvature radius and biconical tapered transition length. The experimental result shows that its sensitivity and linearity are greatly increased. Also, this probe has good repeatability, photostability, and long-term stability.

With the rapid development of micro-nano satellite technology, the light and compact design of laser communication receiving terminals has become the current development trend. Quadrant detector is a kind of photodetector of which photosensitive surface quadrant distribution. This characteristic makes quadrant detector not only detect signal of light, but also detect the position of spot. In this paper digital tracking and communication composite receiver for four-quadrant detector is designed. First, the quadrant detector converts the optical signal into an electrical signal. And then the pre-transimpedance amplifier circuit amplifies the signal and converts it into a voltage signal. Next, the A/D module photoelectric signals are converted into digital signals, and the FPGA based digital algorithms perform tracking and communication related signal processing. By theoretical analysis, when the bit error rate is 10^-6, the communication rate is 10Mbps and the signal to noise ratio is 90.09, the detection sensitivity is -45.06dbm. Also it is realized the position resolution of 6.29 μm. Through the software implementation of tracking and communication function, the feasibility of the design is further verified, which lays the foundation for further development of the receiver.

Inside a service function chain (SFC), traffic flow follows a certain route, namely a service function path (SFP), to travel through each service function (SF) entity. A SFP consists of several end-to-end segments, whose source and destination are named anchor node (AN). SFs are located in multiple datacenters (DCs), and inter-DC light-paths need to be provisioned between separated SFs. In this paper, we introduce geography information of optical nodes and DCs, define special geographic distance between ANs in inter-DC elastic optical networks (EONs). Then following minimal geographic distance principle, we propose a geography-based SFP provisioning solution, which contains two heuristic algorithms, named geography-based shortest path and first-fit algorithm (GSP-FF) and geography-based k-shortest paths and first-fit algorithm (GK-FF). These algorithms can compress AN selection procedure extremely in fixed time, which cost little time for the AN selection of resource allocation. And benchmark algorithm use Dijkstra shortest path calculation and first-fit FS selection to allocate IT resources in DCs and FS resources in EONs. Then GSP-FF and GKFF are proposed to provision SFPs efficiently. In our simulation, we compare our proposed algorithms with benchmark algorithm deeply on blocking probability, running time, average hops, average geographic distance, et al. under different traffic load and other simulation environment. We also analyze the trend and reason for the performance difference among these algorithms. According detailed evaluation, simulation proves that the proposed algorithms in this paper could use geographic information efficiently, and achieve lower blocking probability with lower running time compared with the benchmark algorithm.

In view of the demand of space application field for long-life and highly reliable fiber optic gyroscopes, a life evaluation method for fog in space is presented in this paper. The effect of various physical fields on the performance of fiber optic gyroscope is analyzed in this paper. The temperature field and irradiation are the main environmental factors affecting the operating life of fiber optic gyroscope on orbit. The acceleration test method of temperature field and irradiated double stress double temperature point is carried out, and the performance of fiber optic gyroscope under the action of multi physical field is built. An accelerated life test evaluation method for fog is put forward. The life assessment method of fog in space can provide technical support for the design, selection and verification of the long life fiber optic gyroscope.

The traditional underwater laser communication system has less electro-optic conversion efficiency, short lifetime, large volume, low reliability and complex communication systems. Meanwhile, Underwater communication system with bandwidth above 1Mbps level is in urgent need. To solve these problems, a novel LED optical communication system is present which based on full-duplex mode. In order to improve the communication distance and reduce the influence of backscattering and reflection light, a novel method of blue light LED array placement is proposed. A practical optical attenuation estimation algorithm based on different chlorophyll concentration is used to evaluate the feasibility of 50m underwater communication link distance. The MATLAB numerical calculation are given. The simulation results show that the design method of LED array light source proposed in this paper has small size, light weight and simple structure, which can be applied to underwater optical communication in low channel attenuation, Mbps level bandwidth and long distance(>50m).

Polarimetric imagery is a powerful tool in remote sensing because the polarization information of the targets contains surface features, shape, material composition, and surface roughness, which improves applications such as target detection, shape extraction and anomaly detection. For the importance of the quantitative polarmetric remote sensing, the quantitative estimation of the physical characteristics of the target has attracted considerable scientific interests and become the trend of polarimetric imagery. However, because of the spatial scale effect, specifically, in the large detection distance, the quantitative estimation accuracy of the target can be affected by the inhomogeneous target. In this paper, a novel method based on polarization imaging detection to estimate the roughness of inhomogeneous paint surface in outdoor is proposed. A shadowing method was used to eliminate the effect of skylight and improve the estimation accuracy in outdoor experiment. In addition, the correction method based on local variance of roughness distribution was performed to improve the estimation accuracy of inhomogeneous paint. The results showed that the estimation error of roughness for homogeneous paint in two distances were both below 8%. Especially for the target with smaller roughness, after the correction, the estimation accuracy of inhomogeneous paint were below 6% in two detection distances, which confirms the effectiveness of estimation approach and verifies the practicality of the correction method to improve the estimation accuracy of inhomogeneous target in polarimetric imaging remote sensing detection. The approach presented in this paper has important significance for the development of the quantitative remote sensing, especially for targets with inhomogeneous surface.

We designed and implemented a dynamic simulation platform for software defined optical satellite networking. It can simulate all nodes in satellite network on one computer. It can refresh the network in real time in a highly dynamic and complex environment, including changes in the connection between nodes caused by the dynamic periodic motion of the satellite and changes in link quality, etc. In addition, the platform can apply other algorithms in the simulation network so that the platform is practical and scalable. We also conducted the test of the small satellite constellation on this platform. The experimental results obtained are in line with expectations and reflects the practical capabilities of the platform.

The performance monitoring of fiber-optics communication is an important task in nowadays communication system. Link optical noise-to-signal ratio (OSNR) is one of the most important parameters that affect the performance of optical networks. The traditional internal measurement method may increase the network construction cost and operation complexity. To overcome these drawbacks, an ANN based link OSNR estimation method with external measurement is proposed in this paper. Route level OSNR values are measured at the edge nodes and are used for link level OSNR estimation with the trained ANN. Besides, a heuristic method for route set generation is proposed to generate the route set that introduce fewer extra network load. The experiment results demonstrate that the ANN based method can meet the practical requirement in both estimation accuracy and computation complexity. The proposed method can be an important part of optical network OSNR monitoring to ensure robust and intelligent network operation.

One of the main tasks of the spacecraft is to carry out long-term spaceflights, science research and other activities. For different scientific applications, we need to know about the strain of cabin for evaluating the health condition of spacecraft. Here, two factors mainly work. One is the temperature, and another is refueling operations. For the latter, it is necessary to carry out the unscheduled refueling for life or experiments. The advantages of FBG sensor is suitable for application in aircraft. This paper shows the detection of static and dynamic strain under in flight environment of a certain aircraft by FBG sensors and resistance strain gauge. In the static strain detection, taking the resistance strain gauge as measurement standard, FBG sensors have a large measurement error. For example, for testing position "A", the initial error is around 28.13%. After thermal compensation of bulkhead for FBG sensors, error value reduces to 5.95%. After thermal compensation of bulkhead both for FBG sensors and resistance strain gauge, error value reduces to 0.36%. In the dynamic strain measurement, the impact test of different positions in the same height and different heights on the same position for the bulkhead is carried out. The results show that the two measurement methods are accordant in high frequency and able to identify impact signals effectively. It is very important for structure prediction and health assessment.

We experimentally demonstrate a 8×8, 200 GHz cyclic AWG router using silicon oxynitride waveguides. The relative refractive index difference between the core and cladding layers is 9.75%. The output spectral response when light of TM polarization is input from the central input channel shows the central channel loss, non-uniformity and crosstalk are -1.51 dB, 2.23 dB, and -19 dB, respectively. And when light is input from the edge input channel, the central channel loss, non-uniformity and crosstalk are -3.68 dB, 2.38 dB, and -19 dB, respectively. Crosstalks vary from -19 dB to -21 dB for all channels. The device is polarization sensitive and a polarization dependent wavelength shift occurs in the spectral response of each output channel. The central wavelengths from central input channel to central output channel for the TE and TM polarization are 1553.8 nm and 1550.2 nm.

Ultrasonic nondestructive testing plays a more and more important role in modern production and construction. In this paper, a novel ultrasonic energy transfer technique based on peanut shape structure is proposed and demonstrated. The ultrasonic device is able to effectively couple the laser energy in the fiber core to the cladding of the single-mode fiber (SMF) by using the micro machined fiber structure. The laser energy coupled to the cladding can be absorbed by the ultrasonic conversion material coated on the surface of the SMF. Due to the ultrasonic conversion material has high thermal elastic coefficient, it can produce mechanical expansion and contraction process after absorbing the laser, resulting in the generation of the ultrasonic signal. The ultrasonic transducer based on peanut shape taper only needs to be fused by SMF and fiber splicer. The proposed laser-ultrasonic transducer has many advantages, such as simple preparation, cost-effective, and high energy conversion efficiency. Such characteristics makes the proposed laser-ultrasonic transducer attractive for practical applications.

An all-fiber Fabry-Perot interferometer (FPI) strain sensor based on offset splicing fibers and Vernier effect is proposed and experimentally demonstrated. The proposed sensor consists of two separated air-cavity FPIs connected by a long section of single mode fiber (SMF) in a fiber link. The two separated FPIs have approximately equal optical paths, so that the Vernier effect can be generated. One FPI is used as the sensing FPI (SFPI) for strain measurement, which is formed by splicing a section of microfiber between two SMFs with large lateral offset. The other FPI is used as the reference FPI (RFPI) to employ the Vernier effect and amplify the sensitivity, which is formed by splicing a section of silica tube between two SMFs. Compared to a single FPI based sensor, the strain sensitivity of the proposed sensor with Vernier effect can be improved by tens of times. The strain sensitivity of our proposed sensor reaches 1.3 nm/με, which is the highest strain sensitivity of fiber sensor based on FPI and wavelength demodulation mechanism. Since the aircavity SFPI is insensitive to temperature, the proposed sensor also exhibits low temperature sensitivity of 50.2 pm/℃. With the advantages of high strain sensitivity, low temperature cross-sensitivity, compact size and easy fabrication, the proposed sensor has great applications in many fields.

To meet the need of the measurement in high temperature and high pressure in oil and gas well, an optical fiber extrinsic Fabry Perot (F-P) cavity pressure sensor based on bellows is developed. The probe of the sensor is fabricated by CO2 laser thermal bonding in high temperature technique, and is fixed and sealed by high temperature hot melt of low melting point glass solder and adhesive. The measured medium is isolated from the fiber F-P cavity by corrugated diaphragm which can transmit pressure simultaneously, and the change of the length of F-P cavity is compensated in temperature changing with cascading fiber bragg grating.The sensor has characteristics of large dynamic range, high resolution, high repeatability, long term operation stability and high temperature resistance. The pressure measuring range is 0~71MPa, the repeatability is 0.02% F·S, the hysteresis is less than 0.02% F·S, the long term stability is less than 0.03MPa/y, and the sensor can satisfy the requirement of the measurement in the oil and gas well.

A compact temperature sensor with highly germanium-doped fiber (Ge-fiber) is experimentally demonstrated. It is based on an in-line Michelson interferometer, which is constructed by splicing a 1mm-long, 75 mol.% GeO₂-doped fiber to a single mode fiber (SMF) and fusing the tip into rounded shape. Since the differential refractive index of the Ge-fiber is much higher than that of normal fibers, length of the proposed sensor probe has been greatly reduced. The rounded surface provides as a concave mirror to enhance the reflection, thus leads to a high extinction ratio to the interference fringes. By monitoring wavelength shift of the reflection spectrum, temperature measurement was realized with a high sensitivity of 89.5 pm/°C, which is much higher than normal fiber based MI sensors owing to higher thermo-optic coefficient of the Ge-fiber. The advantages of the sensor are its compact size, facile fabrication and high sensitivity, which make it a potential candidate in point measurement of temperature.

We propose a simple distributed sensor with millimeter-order spatial resolution using a multichannel fiber Bragg grating (FBG). The multichannel FBG was designed by using the layer peeling (LP) algorithm with a tailored group delay characteristic, in which each channel is spatially separated. The multichannel FBG can be easily used in a low cost WDM sensing system for distributed sensing with millimeter-order spatial resolution.

A accurate position method for distributed fiber grating system based on code division multiplexing technology is proposed. In this paper, by using the fiber grating characteristics and code division multiplexing technology, the system are optimized. By designing delay interferometer, the optical signal modulation and demodulation are gained , which effectively improve the system's signal to noise ratio. Through the simulation experiment, the positioning detection is realized by discriminating the fiber gratings at different positions on the optical fiber. Experiments were carried out on 6m and 2.2km optical fibers respectively, the preliminary results proved the correctness and feasibility of the method.

Compared with the traditional geosynchronous orbit earth and medium earth orbit satellite communication systems, the low earth orbit (LEO) satellite communication system has the real-time communication capability of all time, all weather and all terrain, which is the only way to achieve seamless coverage of global mobile communication. A seasonal autoregressive integrated moving average (S-ARIMA) model is used for satellite load forecast. Traffic load measured by the first N satellites is processed to obtain stationary sequence via difference and seasonal difference. Then on the basis of traffic load forecast, the corresponding resource management strategy is selected in light load scenario or heavy load scenario. Light load scenario is limited-coverage, satellite parameter adjustment can enlarge the coverage of beams to reduce resource waste as far as possible. Heavy load scenario is limited-capacity, satellite parameter adjustment can narrow beam coverage and reduce the amount of traffic load. Simulation results show that S-ARIMA model can accurately forecast the load of satellites, and the proposed method can improve resource utilization and reduce energy consumption of satellites.

As light emitting diode (LED) based visible light communication (VLC) is getting increasingly widely used, amplitude jitter is still a common phenomenon in pulse amplitude modulation (PAM) VLC system, which deteriorates the system performance to a large extent. In this paper, we propose a novel signal decision method employing density-based spatial clustering of applications with noise (DBSCAN) of machine learning to distinguish different signal levels with jitter. Not only do we experimentally demonstrate that the Q factor of a PAM-4 VLC system employing DBSCAN is improved by up to 3.9dB, but also investigate the influence of jitter with different levels on PAM-4 system. As far as we know, this is the first time that DBSCAN has been successfully employed in PAM-4 VLC system.

The core of the high-precision aerostatic rotary table is the aerostatic bearing shafting, including radial bearing and axial bearing. The axial bearing is composed of floating plate and thrust bearings. While, the axial bearing is still processed by manual grinding in China, leading to low machining efficiency, high labor costs and difficult consistency of accuracy.

This paper presents a technology about processing high-precision aerostatic rotary table by SPDT (Single Point Diamond Turning) based on LODTM (Large Optics Diamond Turning Machine) to improve the deficiencies leading by manual grinding. The technology uses single crystal diamond cutting tools for ultra-precision machining, and thus can obtain high-precision optical mirror, which can be adopted in the aerostatic rotary table. An experiment for tin bronze samples has been done to demonstrate the availability of the technique, and a pair of high-precision thrust bearings are obtained. The precision of the thrust bearings, detected through precision optical measurement and precision coordinate measuring technology, is better than the designed requirement. The experiment results show that thrust bearings generated by deterministic ultra-precision machining technique based on LODTM will have advantages in figure accuracy and roughness and so on, which can be helpful to improve the precision and low the cost of high-precision aerostatic rotary table. The high-precision thrust bearings are processed by this way, and the high-precision aerostatic rotary table has been assembled.

The investigation of using FBGs to sense chemical and biological reactions/targets is relatively new, the main reason is that the evanescent field generated in FGBs is largely confined within the core, resulting in its insensitivity to the environment. Several approaches have been proposed to enhance the evanescent field of FBGs, e.g. decladding, long period grating optical fiber biosensor, the coupled cladding mode by tilted FBG, functionalized Penta micro-structured optical fiber with FBG. All the approaches above require sophisticated manipulation of FBG or complicated sensor system design, or have extreme limits on the RI range of targets, which induce uncertainty in the preparation of the sensors, reduce the repeatability and accuracy of these methodologies, and increase the biosensor cost. This paper proposes a methodology to combine Surface Plasmon Resonance (SPR) and FBGs. SPR biosensor has been reported to deliver a sensitivity of the order of 10-7 RIU, which is about 100 times better than the sensitivity that can be achieved by FBG biosensors according to published results so far. Microfluidic system is specially designed for this SPR-FBG biosensor, enabling specified various types of surface treatment for each SPR-FBG binding site while minimizing the request of sample volume. The FBGs is designed in such a way that the sensing sites can be rearranged to arbitrary pattern in order to best fit into applications, possessing a potential of manufacturing compact and wearable sensitive biosensors in the future.

In order to reduce the false alarm rates of optical fiber perimeter systems, this paper proposes a signal recognition method based on optoelectronic reservoir computing (RC) to identify pedestrian intrusion signals from various vibration signals acting on the sensing fiber. The optoelectronic reservoir consists of a single nonlinear node and an optoelectronic feedback loop. The nonlinearity of the reservoir is provided by a Mach-Zehnder intensity modulator. The walking signals were acquired in the laboratory through a distributed optical fiber sensing system based on an in-line Sagnac interferometer. The input data of the reservoir is a random combination of walking signals and the output signals of the sensing system under no interferences. The training input data contain three walking signals at different times. The testing input data contain one walking signal according to the most common case. The average identification rate (IR) for the testing data of 10 different walking signals is as high as 97.3%. The highest IR is 99.3%. The simulation results show that the proposed recognition method of intrusion signals of optical fiber perimeter systems is feasible and effective. RC, as an improved training algorithm of recurrent neural networks, has no need of a large number of samples in the training process and seeking the signal features for the signal recognition task. Therefore, the proposed intrusion signal recognition method based on optoelectronic RC is fast in recognition speed and low at cost.

The conventional electronic accelerometer meets electromagnetic compatibility problem in environments with strong electromagnetic filed. We herein design an all-optical accelerometer to solve this problem. A series of miniature plane spring-mass components were micromachined on silicon wafer by means of lithography and reactive ion etching. These components were served as sensitive structures. The fiber-optic extrinsic Fabry-Perot interferometer is adopted as the sensing structure. Two reflectors, one of which is cleaved fiber end while the other is sensitive structure with Au film, are used to constitute the F-P cavity. The proposed structure did not require high-precision alignment. Therefore, it is easily fabricated. The assembled sensor possesses small volume, which is 5 mm in radical and 12 mm in longitudinal. High-precision interferometric optical phase detection technique is used for signal recovery. The sensitivity of the fabricated sensor is about -11.2 dB re. rad/g with the resonance frequency at 2530 Hz. The equivalent noise acceleration is about 31.2 μg/√Hz. All these experimental results indicated a high-performance accelerometer. The fabricated accelerometer has potentials in large engine testing.

Phase-sensitive optical time domain reflectometry (Φ-OTDR) is a promising approach for detecting and locating vibration signals along the whole fiber link. In this paper, a novel high-speed and complete signal transmission scheme based on field programmable gate array (FPGA) and universal serial bus (USB) 2.0 is proposed and applied in the Φ-OTDR system to obtain real-time vibration location. By using the novel scheme, only the effective data is selected and transmitted to the upper system for post-processing in real time. In the experiment, the vibration signals are simulated by hand-clapping, 50 Hz square waves and 400 Hz sine waves. The experimental results demonstrate that the proposed system exhibits good frequency response for vibrations below 1 kHz over 12 km fiber length. In addition, repetition vibration tests are carried out on 4.633 km and 10.022 km, and the location error is within the range of -7 m to +11 m. Therefore, the proposed system holds considerable potential for real-time vibration location and may have a wide application range in areas such as intruder detection, premier security, oil/gas pipeline leakage detection, and railway infrastructure monitoring, etc.

The long-range pipelines for coalbed methane (CBM) transport are generally laid in the field with wide coverage and under harsh operating condition. Most conventional electronic sensing technologies are not appropriate for CBM pipeline safety monitoring featuring long distance, large-capacity measuring points, and severe working condition. In view of above problems, the multi-parameter optical fiber sensing is proposed. For preventing third-party damage, a vibration sensing scheme is designed based on Φ-OTDR principle. For leakage prewaring, a ROTDR-based temperature detection scenario is realized. For pipe deformation precaution, a BOTDR-based strain sensing solution is exploited. Additionally, a cloud database is built on the server for online monitoring. The experimental results demonstrate that: the sensing range of vibration can be 12km with the 20-m spacial resolution and 8-m positioning accuracy; the temperature measurement accuracy is ±1° within the temperature range -25°~200° over the range of 10 km optical fiber; the strain measurement range is 11000 με when the measured distance is about 10 km and the spatial resolution is 1.23m. The multi-parameter detection approach by optical fiber sensing provides a new monitoring method for the safety prewaring of long-range CBM pipelines.