WDM/OTDM混合光网络节点中数据格式转换的数值模拟

本文研究了基于半导体光放大器交叉增益调制(XGM -SOA)效应的波长转换器在WDM/OTDM混合光网络节点数据格式转换中的应用。利用通用的分段动态模型,模拟了速率为10Gbit/s两信道波分复用信号的时分复用和经色散移位光纤传输及色散补偿后的时分复用信号的解复用。转换后信号变换宽度宽,消光比性能好。模拟结果为系统设计和混合光网络交换节点信息处理提供了理论依据。     

光纤环形腔半导体激光器全光波长转换特性分析

提出了一种基于光纤环形腔半导体激光器的全光波长转换方案。利用稳态速率方程,导出了激光器有源区载流子密度与偏置电流及输入信号光功率关系的隐函数表达。从而研究了待转换的信号光及偏置电流对转换光功率和消光比的影响。     

基于单端SOA波长转换器的消光比特性分析

对一种基于单端半导体光放大器(SOA)的交叉增益调制型(XGM)全光波长转换器结构建立了动态理论模型,以这个模型为基础分析了抽运光功率、探测光功率、剩余反射率、转换波长转换间隔、注入电流对转换后探测光的输出消光比的影响.结果表明,利用单端SOA实现波长转换比普通SOA实现波长转换将获得更好的输出消光比特性.     

SOA-XGM全光波长变换器的特性分析

对基于半导体光放大器交叉增益调制实现的全光波长变换器的工作特性进行了分析，归纳了要取得较好的变换效果，应在输入信号光功率、波长、偏置电流、放大器腔体长度等方面作合理的选择，使输出信号的消光比、信噪比等指标符合要求。     

基于LOA的XGM全光波长转换消光比特性的研究

建立了线性光放大器(LOA)的交叉增益调制(XGM)波长转换理论模型.着重讨论了抽运光与探测光的波长和功率、LOA中分布式布拉格反射镜(DBR)的反射率和注入电流等参量对输出消光比特性的影响.结果表明,输出消光比随着抽运光(探测光)波长的增加而增加(减小);适当的减小探测光功率和选择合适的注入电流可以获得较大的消光比;波长向下转换时的消光比明显优于向上转换时的消光比;同样,提高LOA中DBR的反射率,也可以获得较高的消光比.     

基于级联半导体光放大器中交叉增益调制效应的新型全光逻辑与门

提出一种基于级联半导体光放大器(SOA)中的交叉增益调制(XGM)效应实现的全光逻辑与门新方案。该方案采用单端耦合半导体光放大器提高第一级半导体光放大器输出的消光比，合理控制第二级半导体光放大器的输入光功率，实现了两路2．5Gbit／s非归零(NRZ)信号的逻辑与运算。详细阐明了基于级联半导体光放大器的与门的工作原理和实验方案，分析了实验结果。根据实验结果，发现第一级半导体光放大器输出信号的消光比和信噪比对逻辑与运算结果影响较大，利用单端耦合半导体光放大器后能改善逻辑与运算结果，第二级半导体光放大器的输入抽运光功率对逻辑与运算输出的信号质量有较大的影响。合理控制这些因素，可以有效地提高该逻辑与门的输出特性。     

增益调制型波长转换中信号光波长的选择

增益调制型波长转换中 ,为得到转换后信号最大的消光比 (ER) ,信号光波长应该比半导体光放大器 (SOA)的小信号增益峰值波长长。采用分段模型 ,考虑了SOA中增益谱的不对称性以及增益峰值波长随载流子密度的漂移 ,深入研究了信号光功率 ,ER ,参考光功率 ,波长以及SOA注入电流对选择信号光波长λpk ,s 以及消光比改善量的影响。模拟计算表明 ,信号光功率每增加 3dB ,λpk ,s 就需向长波长移动约 7nm。信号光ER增加、参考光功率增加以及SOA注入电流的增加 ,λpk ,s 需向短波长移动。消光比改善量随信号光功率和电流的增加而显著增加 ,随信号ER的增加而降低 ,但是参考光功率和波长变化时影响不大     

基于XGM的SOA波长变换器噪声特性分析及实验研究

本文将半导体光放大器的ASE噪声功率引入到SOA分段动态模型,得到随SOA长度变化的ASE噪声功率,并讨论了偏置电流、泵浦光功率、SOA长度对变换性能影响.理论计算结果表明,大的偏置电流有利于提高消光比(ER)和信噪比(SNR);对于长度一定的SOA和一定的偏置电流,泵浦光功率存在最佳值;SOA长度存在信噪比最佳值.我们对2.5Gbit/s SDH信号进行了XGM方式波长变换,实验结果与理论分析一致.     

基于半导体光放大器-交叉增益调制波长转换器消光比特性的研究

建立了基于半导体光放大器一交叉增益调制(SOA-XGM)的波长转换理论模型，利用分段方法对交叉增益调制波长转换器同向和相向两种工作方式下消光比(ER)特性作了详细的研究。结果表明，波长转换器的输出消光比随转换速率增加而减小，而且转换速率越高，减小得越快；随着抽运波长的变化，消光比有一个对应于峰值增益波长的最佳抽运波长；波长向下转换(Δλ＜0)时的消光比要明显优于向上转换(Δλ＞0)；输出消光比也随着输入消光比的增大而增大。相同情况下相向工作方式时的输出消光比特性要优于同向工作方式。最后，从物理上对两种工作方式消光比和噪声特性的差异作了解释。     

基于QD-SOA交叉增益调制的波长转换研究

量子点半导体光放大器具有比传统半导体光放大器更快的载流子恢复时间,基于QD-SOA交叉增益调制的波长转换技术具有转换速率快,无pattern effects效应的特点.对有源区长度,输入信号光功率和转化后信号的消光比和脉冲展宽进行了研究,对提高基于QD-SOA交叉增益调制波长转换的性能具有指导意义.     

基于半导体光放大器的四波混频效应对正交频分复用光信号进行全光波长变换

实验研究了基于半导体光放大器(SOA)的四波混频(FWM)效应的单抽运光正交频分复用(OFDM)信号的波长变换系统.信号光源和抽运光源分别由两个不同输出波长的可调分布反馈式激光器(DFB-LD)产生.信号光源经2.5 Gb/s OFDM的电信号直接调制后再和抽运光源耦合,经光放大器后在SOA实现波长变换.实验结果显示,耦合信号经SOA四波混频效应后,产生新波长的信号光将携带OFDM信号,且转换效率与信号光和抽运光的功率、波长以及两者的偏振夹角有关.同时也测量了转换的OFDM信号的功率-误码曲线和接收星座图.     

Structural modification of semiconductor optical amplifiers for wavelength division multiplexing systems

In this paper, the semiconductor optical amplifier is analyzed for in-line and pre-amplifier for wavelength division multiplexing (WDM) transmission having minimum crosstalk and power penalty with sufficient gain. It is evaluated that the cross gain saturation of the SOA can be reduced by settling crosstalk at lower level and also minimizing the power penalty by slight increase in the confinement factor. At an optimal confinement factor of 0.41069, high amplification is obtained up to saturation power of 20.804 mW. For this confinement factor, low crosstalk of −9.63 dB and amplified spontaneous emission noise power of 119.4 μW are obtained for −15 dBm input signal. It has been demonstrated for the first time that twenty channels at 10 Gb/s WDM can transmit up to 5600 km by use of this optimization. In this, cascading of in-line SOA is done at the span of 70 km for return zero differential phase shift keying modulation format with the channel spacing of 100 GHz. The optical power spectrum and clear eye are observed at the transmission distance of 4340 and 5600 km in RZ-DPSK system. The bit error rate for all channels increases more than 10⁻¹⁰ with the increase in launched input power.     

全光光孤子WDM到OTDM转换的概念系统

提出了在未来的光孤子波分复／时分复用网络中由ＷＤＭ到ＯＴＤＭ节点处的转换复用的概念系统，主要的模块是完成波长转换的基于交叉增益调制的半导体光放大器，同步和延时及时分复用模块。通过ＳＯＡ可以实现全光的ＷＤＭ到ＯＴＤＭ的波长转换复用，是ＷＤＭ／ＯＴＤＭ网络实用化的一个关键部分。     

Increasing input power dynamic range of SOA by shifting thetransparent wavelength of tunable optical filter

Gain-saturation-induced self-phase modulation (SPM) leading to pulse distortion in a semiconductor optical amplifier (SOA) is overcome by shifting a tunable optical filter (TOF). A recovered or broadened pulse can be obtained after filtering the amplified pulse in the SOA even if the short pulse is only 2-3 ps long. The input power dynamic range (IPDR) can be strongly increased by shifting the TOF and the direction of the shifted transparent wavelength is different for 10 Gb/s return-to-zero (RZ) or nonreturn-to-zero (NRZ) signals. The transparent wavelength of the TOF should be shifted to a longer wavelength for RZ signals and to a shorter for NRZ signals. 80-Gb/s optical time division multiplexing (OTDM) signal amplification in the SOA is demonstrated for the first time. We also demonstrate that a large IPDR for the 80-Gb/s OTDM signal can be obtained by shifting the TOF     

基于半导体光放大器的四波混频型全光波长转换器

本文报道了基于自行研制的半导体光放大器（SOA）的四波混频（FWM）型全光波长转换,采用环型腔掺铒光纤激光器（EDFL）作为泵浦源,实现了转换波长的连续可调。并就波长转换间距、光放大器的小信号增益和输入泵浦光功率对转换效率的影响进行了理论与实验分析,结果表明高的SOA增益和较大的输入泵浦光功率须利于转换效率的提高。     

OTDM transmitter using WDM-TDM conversion with an electroabsorptionwavelength converter

An all-optical multiplexing technique using wavelength division multiplexing (WDM)-time division multiplexing (TDM) conversion with an electroabsorption wavelength converter has been proposed and demonstrated. The effectiveness of this WDM-TDM conversion technique for various pulsewidth settings was experimentally investigated. The fluctuation of the signal performance, which was inevitably caused by the coherent crosstalk between adjacent pulses in the conventional optical time division multiplexing (OTDM) technique, were successfully suppressed, even in the case of wide pulse duration. High Q-factor performance has been maintained for a wide range of duty ration from 36% to 74%. By introducing this technique to the optical time division multiplexer, a highly stable and high-quality 40-Gb/s optical signal can be effectively produced without generating the short pulse or setting two tributaries at orthogonal polarization states, and without introducing high-speed electronics for signal multiplexing. The WDM-TDM conversion with an electroabsorption wavelength converter was extended to 60-Gb/s operation by using three 20-Gb/s tributaries. A clear eye opening was confirmed for a waveform after the WDM-TDM conversion of the 60-Gb/s signal