SAC-OCDM/TDM system for upgrading the TDM PON

A spectral amplitude coded-optical code division multiplexing time division multiplexing(SACOCDM/TDM) passive optical network(PON) for upgrading the traditional TDM PON is proposed.To the best of our knowledge,our work is the first to report on the use of both spectral and orthogonal code domains,which are transparent to optical network unit(ONU) for hybrid PON,in order to upgrade TDM PON seamlessly.The fewer encoder/decoders and cheaper optical source under the conditions of high bite rate and large ONU ac...     

光频域反射技术中激光相位噪声影响分析

研究了光频域反射技术(OFDR)中因激光线宽有限而造成的激光相位噪声对系统性能的影响.理论推导了相位噪声的分布函数,仿真分析和实验测试了激光相位噪声与激光相干长度、反射信号强度之间的内在关联性.研究结果表明,激光相位噪声是OFDR中的重要噪声来源,影响着系统的测试精度和可测距离,当测试距离接近相干长度、链路中存在强的反...     

10 Gb/s symmetric WDM-PON using stable multi-longitudinal mode Brillouin/SOA fiber laser as upstream colorless source

We propose a stable multi-longitudinal Brillouin/semiconductor fiber laser(BSFL) as the upstream source in a bidirectional single-fiber wavelength-division multiplexing-passive optical network(WDM-PON).The downstream wavelength serves as the pump of the BSFL.Brillouin-frequency-shifted(～10.8 GHz) upstream carrier is generated to suppress the Rayleigh backscattering and back reflection-induced crosstalk.The stable multi-longitudinal operation of the BSFL,attributed to the four-wave mixing(FWM) effect in the semiconductor optical amplifier(SOA) reduces the difficulty of generating a stable single-longitudinal fiber laser-based upstream carrier.Bidirectional symmetric transmission at 10 Gb/s over a 12.5-km single mode fiber with less than 2-dB power penalty is demonstrated.     

All-optical reconfigurable multi-logic gates based on nonlinear polarization rotation effect in a single SOA

We demonstrate an all-optical reconfigurable logic gate based on dominant nonlinear polarization rotation accompanied with cross-gain modulation effect in a single semiconductor optical amplifier (SOA).Five logic functions,including NOT,OR,NOR,AND,and NAND,are realized using 10-Gb/s on-off keying signals with flexible wavelength tunability.The operation principle is explained in detail.By adjusting polarization controllers,multiple logic functions corresponding to different input polarization states are separately achieved using a single SOA with high flexibility.     

Performance analysis of all optical swapping networks with a label eraser made of a Gaussian filter

In this paper, a simple label eraser employing Gaussian apodized fiber Bragg grating (FBG) for all optical label swapping (AOLS) networks is proposed. Relying on the analysis of the payload through multi-stage erasers, this kind of eraser significantly improves the cascadability in comparison with the traditional fiber-loop mirror (FLM) eraser. The influences of the residual labels on the intermediate swapping node labels through the eraser are also investigated. It is shown that the power penalty is only less 1 dB when the optical power ratio of residual label to the new label signal arrives at -8 dB. The influence is negligible due to the sharp notch filtering effect of the Gaussian apodized FBG.     

两个错解 一个错因

例1判定函数‘(X’“二一,,i少通-X的奇偶性解:j(一二)二(一x一l)_}牛等丫1个x一(二+,).{旱· V孟一3I+工一广一.l一Xl一Xl+xC山、、.,/义X一十/诊飞、、一(义十,,了l+x1一义_,.、{1+二_,,一、弄一l产.1.--一一J气X) 、l一义-.’. j(x)为偶函数.(二;)(C)(一Jo。,,1 00二〕;(方夕之一、,o〕〔Zk汀ZL,::十一乒)寿〔z 公上的非周期函数是(),周期为2二的周期函数是(). 答:非周川函数是(C).局拟为2二的函数是(A)和(B). 仔细检查上述两题的解答.发现它叮沛是错误的. 关于题1,函数具有奇(偶)!生的一个必要条件是梦定义城关于原点对称.九)’…     

相干激光通信系统光学锁相环路载波恢复技术

基于科斯塔斯(COSTAS)光学锁相环路载波恢复进行建模分析,得到系统的闭环传递函数、误差函数及需要恢复的载波信号;设计系统采用复合控制,内环借助声光移频器实现快速、小范围跟踪,外环通过环路直接控制激光器拉进快捕带;为了得到良好的载波恢复和信号解调,设计基于异或门的COSTAS环鉴相模块对鉴相器进行分析,实现鉴相范围为[-42°,42°],鉴相增益为14.4mV/(°),在环路带宽为1.5 MHz时,搭建实验进行测试。实验结果表明在码速率5Gb/s时,载波恢复、信号解调良好,信号光功率为-40.4dBm时,误码率为1.55×10-8,随着速率的提高或降低,系统性能虽有下降,但仍能恢复载波信号并解调数据,为零差相干通信实验室验证提供了参考。     

非线性相位噪声对DQPSK调制系统性能影响研究

为了研究非线性相位噪声对差分正交相移键控（DQPSK）调制系统性能的影响,在理论推导非线性相位噪声数学模型的基础上,通过固定接收端信噪比不变,仿真分析了40Gb/s速率时DQPSK调制系统误码率随输入信噪比的变化情况。结果表明:与二进制差分相移键控（DPSK）调制相比,DQPSK调制对非线性相位噪声的影响更为敏感,当非线性效应较大时,非线性相位噪声将使系统误码率显著增大,严重影响系统通信质量。因此,当采用DQPSK调制时,必须考虑非线性相位噪声对系统性能的影响。     

面向天线组阵的光载微波光纤稳定传输技术

光载微波光纤稳定传输技术解决了天线组阵中所需的延时（或相位）稳定的微波信号远距离分配难题，在多天线协同的新一代微波测量中具有不可替代的作用。本文介绍了光载微波光纤稳定传输的基本理论，分析了制约传输稳定性的关键因素，并展示了基于相位预补偿和基于光延时校正的提高传输稳定性的技术途径。通过光电双外差混频的相位检测高灵敏地感知光纤链路延时变化，并分别利用微波相位调控和光延时调控来对这一变化进行高精度的补偿，最终实现了多路时间抖动在数十fs量级的高稳定光载微波传输，为天线组阵等多天线协同微波测量中的信号级同步提供了有效的解决方案。