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Time Domain Synchronous OFDM System for optical fiber communications

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China communications 2019年第9期16卷 155-164页

作者： Chenxin Jing Xianfeng Tang Xiaoguang Zhang Lixia Xi Wenbo Zhang State Key laboratory of Information Photonics and optical communications Beijing University of Posts and Telecommunications

A spectrum efficient OFDM scheme named Time Domain Synchronous-OFDM(TDS-OFDM)is introduced into coherent optical transmission system,in which the pseudo noise(PN)sequence is exploited as guard interval to realize frame synchronization,compensate the carrier frequency offset(CFO),and estimate and equalize channel *** there is no pilot signals or training symbols in TDS-OFDM,the proposed scheme can achieve higher spectral efficiency(SE)above 10%improvement comparing with *** proposed method is implemented and verified in a 28GBaud QPSK OFDM system and a 28GBaud 16QAM OFDM *** is demonstrated that the proposed scheme shows high CFO estimation accuracy and synchronous *** CFO and linewidth of laser source set as 100MHz and 100kHz respectively,BER of QPSK OFDM system is below 3.8e-3 at the optical signal-to-noise ratio(OSNR)of 13dB,and BER of 16QAM OFDM system is below 3.8e-3 at the OSNR of 20dB.

关键词： channel estimation carrier frequencyoffset (CFO) compensation pseudonoise (PN) sequence synchronization timedomain synchronous OFDM (TDS-OFDM)

Generation of multi-wavelength light sources for optical communications in aperiodic optical superlattice

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Chinese Optics Letters 2005年第12期3卷 708-711页

作者：吴飞陈险峰曾祥龙陈玉萍夏宇兴 Department of Physics State Key Laboratory on Fiber-Optic Local Area Communication Networks and Advanced Optical Communication SystemsShanghai Jiao Tong UniversityShanghai 200240

A method for generating multi-wavelength light source is theoretically investigated by optical parametric oscillation （OPO） in aperiodic optical superlattice （AOS）. The effects of domain errors caused by the ro om-temperature electric poling process are checked. The relationship between the linewidth and the block length is also discussed.

关键词： Dense wavelength division multiplexing Light sources Microstructure optical communication

A novel decoding algorithm based on the hierarchical reliable strategy for SCG-LDPC codes in optical communications

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Optoelectronics Letters 2013年第6期9卷 469-472页

作者：袁建国仝青振黄胜王永 Key Lab. of optical fiber Communication Technology Chongqing University of Posts and Telecommunications

An effective hierarchical reliable belief propagation(HRBP)decoding algorithm is proposed according to the structural characteristics of systematically constructed Gallager low-density parity-check(SCG-LDPC)*** novel decoding algorithm combines the layered iteration with the reliability judgment,and can greatly reduce the number of the variable nodes involved in the subsequent iteration process and accelerate the convergence *** result of simulation for SCG-LDPC(3969,3720)code shows that the novel HRBP decoding algorithm can greatly reduce the computing amount at the condition of ensuring the performance compared with the traditional belief propagation(BP)*** bit error rate(BER)of the HRBP algorithm is considerable at the threshold value of 15,but in the subsequent iteration process,the number of the variable nodes for the HRBP algorithm can be reduced by about 70%at the high signal-to-noise ratio(SNR)compared with the BP *** the threshold value is further increased,the HRBP algorithm will gradually degenerate into the layered-BP algorithm,but at the BER of 10-7and the maximal iteration number of 30,the net coding gain(NCG)of the HRBP algorithm is 0.2 dB more than that of the BP algorithm,and the average iteration times can be reduced by about 40%at the high ***,the novel HRBP decoding algorithm is more suitable for optical communication systems.

关键词： LDPC码译码算法光通信阳离子光学通信系统 BP算法低密度奇偶校验解码算法

A novel QC-LDPC code based on the finite field multiplicative group for optical communications

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Optoelectronics Letters 2013年第5期9卷 378-380页

作者：袁建国许亮仝青振 Key Lab. of optical fiber Communication Technology Chongqing University of Posts and Telecommunications

A novel construction method of quasi-cyclic low-density parity-check(QC-LDPC) code is proposed based on the finite field multiplicative group,which has easier construction,more flexible code-length code-rate adjustment and lower encoding/decoding ***,a regular QC-LDPC(5334,4962) code is *** simulation results show that the constructed QC-LDPC(5334,4962) code can gain better error correction performance under the condition of the additive white Gaussian noise(AWGN) channel with iterative decoding sum-product algorithm(SPA).At the bit error rate(BER) of 10-6,the net coding gain(NCG) of the constructed QC-LDPC(5334,4962) code is 1.8 dB,0.9 dB and 0.2 dB more than that of the classic RS(255,239) code in ITU-T G.975,the LDPC(32640,30592) code in ITU-T G.975.1 and the SCG-LDPC(3969,3720) code constructed by the random method,*** it is more suitable for optical communication systems.

关键词： LDPC码光通信系统有限域乘法群迭代译码算法低密度奇偶校验加性高斯白噪声 ITU-T

optical Tamm state polaritons in a quantum well microcavity with gold layers

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Chinese Physics B 2012年第5期21卷 532-536页

作者：张伟利饶云江 Key laboratory of optical fiber Sensing and communications of Ministry of Education University of Electronic Science and Technology of China

A new type of cavity polariton,the optical Tamm state（OTS） polariton,is proposed to be realized by sandwiching a quantum well（QW） between a gold layer and a distributed Bragg reflector（DBR）.It is shown that OTS polaritons can be generated from the strong couplings between the QW excitons and the free *** addition,if a second gold layer is introduced into the bottom of the DBR,two independent free OTSs can interact strongly with the QW excitons to produce extra OTS polaritons.

关键词： semiconductor microcavity polariton optical Tamm state surface plasmons

Performance of DRA with different pumping schemes based on coupling equation

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Optoelectronics Letters 2011年第3期7卷 209-212页

作者：袁建国梁天宇何丽何清萍 Key laboratory of optical fiber communications Technology Chongqing University of Posts and Telecommunications

After the coupling equations of co-pumping,counter-pumping and bidirectional-pumping distributed Raman amplifiers(DRAs) are theoretically analyzed,the power distributions of these three DRAs are acquired with numerical *** performance factors,such as net gain(NG),amplified spontaneous emissions(ASE) noise,double Rayleigh backscattering(DRB) noise,noise figure(NF) and optical signal noise ratio(OSNR),are discussed in *** can be found that the NGs of the three DRAs are almost *** counter-pumping scheme will induce higher *** the co-pumping DRA has greater DRB noise,but its NF and OSNR are both better than the others'.Furthermore,the relations between signal power and NG,NF,OSNR are also *** is shown that the NF and OSNR of the co-pumping scheme are superior to those of the other two schemes at small input signal *** above conclusions can play a very important role in guiding the optimum design of DRA.

关键词： Amplifiers (electronic) Light amplifiers Numerical analysis optical signal processing

Experiments and simulation on the overall DMG of long-haul cascade FM-EDFA systems

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Chinese Optics Letters 2024年第4期22卷 53-59页

作者：江歆睿武保剑严伟文峰邱昆 Key laboratory of optical fiber Sensing and communications Ministry of EducationUniversity of Electronic Science and Technology of ChinaChengdu 611731China

All-fiber few-mode erbium-doped fiber amplifiers(FM-EDFAs) with isolation and wavelength division multiplexers(IWDMs)have been developed to enable flexible pumping in different directions. The FM-EDFA can achieve >30 ... 详细信息

关键词： mode division multiplexing few-mode erbium-doped fiber amplifier gain equalization

Phase-Sensitive optical Time-Domain Reflectometry Amplified by Gated Raman Pump

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Photonic Sensors 2015年第4期5卷 345-350页

作者： Yi LI Yi ZHOU Li ZHANG Mengqiu FAN Jin LI Key laboratory of optical fiber Sensing & communications (Ministry of Education) University of Electronic Scienceand Technology of China Chengdu 611731 China

A long-range phase-sensitive optical time-domain reflectometry is proposed and experimentally demonstrated, based on the gated Raman amplification （RA）. This technique can reduce the amplified spontaneous emissions （ASE） noise of the Raman pump while extend the sensing distance. A direct-detection based phase-sensitive optical time-domain reflectometry （O-OTDR） with an operation range of 50 km and a spatial resolution of 20 m has been demonstrated. The influence of different delay time of the gated Raman pump on the O-OTDR system is also discussed.

关键词： fiber optic sensors Rayleigh scattering stimulated Raman scattering

Free-moving-state microscopic imaging of cerebral oxygenation and hemodynamics with a photoacoustic fiberscope

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Light(Science & Applications) 2024年第1期13卷 33-46页

作者： Xiaoxuan Zhong Yizhi Liang Xiaoyu Wang Haoying Lan Xue Bai Long Jin Bai-Ou Guan Guangdong Provincial Key laboratory of optical fiber Sensing and communications Institute of Photonics TechnologyJinan UniversityGuangzhou510632China

We report the development of a head-mounted photoacoustic fiberscope for cerebral imaging in a freely behaving *** 4.5-gram imaging probe has a 9-µm lateral resolution and 0.2-Hz frame rate over a 1.2-mm wide *** probe can continuously monitor cerebral oxygenation and hemodynamic responses at single-vessel resolution,showing significantly different cerebrovascular responses to external stimuli under anesthesia and in the freely moving *** example,when subjected to high-concentration CO_(2) respiration,enhanced oxygenation to compensate for hypercapnia can be visualized due to cerebral regulation in the freely moving *** studies exhibit significantly weakened compensation capabilities in obese *** new imaging modality can be used for investigating both normal and pathological cerebrovascular functions and shows great promise for studying cerebral activity,disorders and their treatments.

关键词： cerebral anesthesia moving