An experiment of automatic PMD compensation in 40-Gb/s RZ optical communication system

An experiment of adaptive polarization mode dispersion (PMD) compensation for 40-Gb/s return-to-zero (RZ) optical communication system is reported. In the experiment, degree of polarization (DOP) is used as feedback signal and particle swarm optimization (PSO) method is adopted as logic control algorithm.The compensation time is about 200 ms, the compensated differential group delay (DGD) is up to 30 ps,and bit error rate (BER) of 10-9 is reached when PMD compensation is employed.     

外色散腔半导体激光器的单模运转

本文对外色散腔半导体激光器单模工作条件及机理进行了理论分析和实验研究。采用将多纵模输出的半导体激光二极管置于外色散腔内,不论二极管表面镀不镀增透膜,都实现了室温连续稳定单纵模运转。激光线宽小于50MHz,调谐范围200(?),单模功率大于无外腔时的多模输出功率,可达3mW。     

实现20Gbit/s的OTDM孤子信号56km色散位移光纤的传输

在国内最先采用孤子的方式将8×2.5Gb/s的OTDM信号在色散位移光纤中传输了56.1km,对8×2.5Gb/s的OTDM进行解复用后进行了误码测量,系统功率代价为2.9dB.系统采用增益开关半导体激光器作光孤子源,高Q电滤波方式提取时钟,非线性光学环路镜解复用。孤子脉冲最大半宽度为20ps,传输光纤平均色散1.2ps/nm/km。     

Two-stage adaptive PMD compensation in 40-Gb/s OTDM optical communication system

An experiment of two-stage adaptive compensation for polarization mode dispersion (PMD) iu a 40-Gb/s optical time-division multiplexed communication system is reported. The PMD monitoring technique based on degree of polarization was adopted. The particle swarm optimization (PSO) algorithm was introduced in adaptive PMD compensation. The comparison was made to estimate the effectiveness between PSO algorithms with global neighborhood structure (GPSO) and with local neighborhood structure (LPSO). The LPSO algorithm is shown to be more effective to search global optimum for PMD compensation than GPSO algorithm. The two-stage PMD compensator is shown to be effective for both first- and second-order PMD, and he compensator is shown to be bit rate independent. The optimum searching time is within one huudred milliseconds.     

Multi-wavelength pulse generation using flattop optical frequency comb and arrayed waveguide grating

A scheme of multi-wavelength pulse generator using optical frequency comb and arrayed waveguide grating (AWG) is proposed and experimentally demonstrated. A flattop optical frequency comb is shaped into multiple narrowband Gaussian spectra by using an AWG which contains a number of Gaussian channels, and then multi-wavelength optical pulses are achieved. In the experiment, six wavelength pulses with full width at half-maximum (FWHM) of 14.6 ps at 10 GHz are obtained, and two wavelength-interleaved pulse trains at 20 GHz and four wavelength-interleaved pulse trains at 40 GHz are demonstrated by using the multi-wavelength optical pulses. This scheme has flexibility because the pulse width, the repetition rate, and time-interval can be readily controlled.     

Two-stage adaptive PMD compensation in 40-Gb/s OTDM optical communication system

An experiment of two-stage adaptive compensation for polarization mode dispersion (PMD) in a 40-Gb/s optical time-division multiplexed communication system is reported. The PMD monitoring technique based on degree of polarization was adopted. The particle swarm optimization (PSO) algorithm was introduced in adaptive PMD compensation. The comparison was made to estimate the effectiveness between PSO algorithms with global neighborhood structure (GPSO) and with local neighborhood structure (LPSO).The LPSO algorithm is shown to be more effective to search global optimum for PMD compensation than GPSO algorithm. The two-stage PMD compensator is shown to be effective for both first- and second order PMD, and the compensator is shown to be bit rate independent. The optimum searching time is within one hundred milliseconds.     

An experiment of automatic PMD compensation in 40-Gb/s RZ optical communication system

An experiment of adaptive polarization mode dispersion (PMD) compensation for 40-Gb/s return-to-zero (RZ) optical communication system is reported. In the experiment, degree of polarization (DOP) is used as feedback signal and particle swarm optimization (PSO) method is adopted as logic control algorithm. The compensation time is about 200 ms, the compensated differential group delay (DGD) is up to 30 ps, and bit error rate (BER) of 10-9 is reached when PMD compensation is employed.     

基于异步光取样的频率空间压缩法瞬时测频方法

瞬时测频技术是一项重要的电子技术。首次提出了一种基于异步光取样的频率空间压缩法瞬时测频方法。测量带宽可以从直流到40GHz,实验结果表明,响应曲线基本保持平坦响应,测频精度超过0.5MHz,可同时测量多个载波信号频率,在0.2μs或者更短时间内就可以完成一次测频。数值模拟表明,抗噪声性能可达-13dB以上,可以提取掩藏在100倍功率人为干扰中的有用信号频率。     

用光电振荡器提取帧时钟实现4×10Gb/sOTDM信号165km传输

本文报道了一个以光电振荡器(OEO)为帧时钟提取装置的4×10Gb/s光时分复用通信实验系统.复用信号在165km SMF中传输的功率代价是0.47dB.     

一种新型高速光保持模块

针对光电混合模数转换系统中采样光脉冲很窄,高速积分保持电路实现较困难这一问题,本文提出了一种新型的高速光保持模块.通过使用多个耦合器组成的无源结构,将采样后的超窄光脉冲转换成一族脉冲簇,再经过光电转换和电低通滤波,得到了顶部较平、脉宽较宽的脉冲,有助于降低后续处理电路的复杂度.实验结果表明,这种结构能够较好地实现将超窄脉冲展宽成平顶宽脉冲的功能.