基于环行腔激光器四波混频型可调谐波长转换的理论研究

建立了完整的基于半导体环行腔激光器四波混频型可调谐波长转换器的宽带理论模型.模型中考虑了半导体光放大器的材料增益谱、载流子的空间分布、光场的纵向空间分布和宽带放大自发发射等关键因素，并通过数值模拟，从理论上研究了这种波长转换器的各种性能与输入信号光功率、注入电流、输出耦合器的耦合比和环行腔激光器激射光波长的关系.理论上所得结论与文献中实验结果符合得很好. 关键词： 半导体环行腔激光器 四波混频 波长转换 放大自发发射     

掺铒光纤非线性耦合器的实验研究

提出一种耦合参量可用光调控的掺铒光纤非线性耦合器.用熔融拉锥法熔合两根掺铒光纤，拉制成工作波长为155nm的3dB掺铒光纤耦合器.通过调变输入耦合器一臂的980nm泵浦光功率，可以改变两臂的传播常量差，从而改变耦合器两臂信号光的相对输出功率.通过测量输入泵浦光功率和两臂信号光输出功率，得到直通臂耦合比依赖于泵浦光功率的实验曲线.实验研究表明，当泵浦光功率从0 mW变化至20 mW时，耦合比的变化可达到40％.与理论模拟的结果一致.     

半导体激光器型全光波长转换器的啁啾分析

利用速率方程分析了转换信号光的频率啁啾,考虑到了外界注入信号光的放大.转换过程中,信号光的注入将会导致了光腔内载流子数发生变化,进而引起激光器输出频率的改变,产生啁啾.研究发现,较大的激光器注入电流可以有效地抑制频率啁啾,较高的注入信号光功率则可以在保证高转换信号消光比的同时抑制频率啁啾.     

基于半导体光放大器中交叉增益调制效应的波长转换啁啾特性的分析

对基于半导体光放大器中交叉增益调制效应的波长转换后信号的啁啾特性进行了分析。研究了输入信号光和参考光和功率、波长、转换速率、信号光消光比以及半导体光放大器的偏置电流对转换后信号啁啾的影响。     

基于光子晶体的量子点半导体光放大器波长转换特性

量子点半导体光放大器(QD-SOA)具有皮秒级的增益恢复时间和超快的载流子浓度恢复等特点,光子晶体(PC)与QD-SOA结合后具有强非线性效应、低吸收损耗、高功率传输和低功耗等优点。研究了光子晶体-量子点半导体光放大器(PC-QDSOA)的波长转换特性,详细分析了最大模式增益、泵浦光功率、探测光功率、有源区长度对PC-QDSOA波长转换Q因子的影响及注入电流、泵浦光功率、探测光功率、有源区长度与PC-QDSOA波长转换消光比的关系,并将PC-QDSOA仿真结果与QD-SOA的仿真结果进行比较。结果显示PC-QDSOA的Q因子和消光比的数值总是大于QD-SOA,说明PC-QDSOA比QD-SOA的输出信号质量更好,信号传输效率更高,转换性能更优越。研究结果对PC-QDSOA的应用具有一定的指导意义。     

基于光纤中受激喇曼散射效应的全光多波长转换耦合器EI北大核心CSCD

基于光纤中受激喇曼散射效应,运用级联同种光纤设计出全光多波长转换耦合器,使转换输出的各路信号光功率相等.建立了全光多波长转换设计方案的理论模型,给出了设计原理框图以及实现方法,并以1路泵浦信号光、4路连续探测光为例,通过OptiSystem软件进行了仿真,仿真结果表明:所设计的全光多波长转换耦合器能同时对4路探测光实现波长转换,转换输出的信号光码型和输入泵浦信号光码型基本一致;转换效率和消光比随着探测光波长的增大而增大,最大值分别为-34dB和36.68dB;Q因子随着探测光波长的增大而减少,最大值为128.29;在级联光纤之后,4路输出信号光峰值功率和消光比基本相等,Q因子整体数值相对于全光多波长转换后有所下降,最大值为89.5455,验证了该方案的可行性.     

量子点半导体光放大器波长转换的Q因子特性

为了改善全光波长转换器的转换性能进而提高输出信号质量,研究了波长转换器的Q因子特性。采用牛顿迭代法和四阶龙格库塔法解光场传输方程和跃迁速率方程,分析了输入信号光功率、脉冲宽度、最大模式增益和有源区长度4个因素对全光波长转换器的Q因子特性的影响,并将得到的结果与相同条件下的输出消光比比较。结果表明:增大输入信号光功率,Q因子先增大后减小,并且在-12 d Bm时取得最大值8.819 d B;Q因子随着脉冲宽度的增加而不断下降;增大最大模式增益和有源区长度,Q因子增大。在实现波长转换的基础上,优化各参数数值,得到的Q因子达到16.680 d B,输出信号质量较好。要同时获得高的消光比和Q因子,提高输出信号的质量,必须选取适当的输入信号光功率、脉冲宽度、最大模式增益和有源区长度。     

半导体光放大器增益及发光特性的理论研究

半导体光放大器(SOA)的非线性特性在光开关、波长变换、光逻辑运算中有重要的应用.研究了注入电流、入射光波长及SOA有源区长度对SOA增益和发光功率的影响.数值模拟结果表明:注入电流的增加,会引起载流子浓度的增加,且使SOA增益趋于饱和的速率加快;不同的SOA模型存在一个最佳输入光波长,在此波长附近有较好的增益特性;加长半导体光放大器有源区长度可获得更大增益,同时提高了器件的响应速率.     

半导体光放大器中光波传输特性研究

根据半导体光放大器(SOA)载流子速率方程和光波在SOA内的传输方程,采用分段的方法计算出光波功率和相位与载流子浓度的关系公式。在泵浦光输入功率分别为5mW和15mW情况下通过仿真得到泵浦光输出波形和归一化转换光波形,其中归一化转换光的波形变化可间接体现不同泵浦光输入功率对SOA内载流子浓度的影响。分析了泵浦光波长和SOA注入电流对探测光的归一化输出、相位和频率啁啾产生的影响。结果表明,随着泵浦光波长的增加,探测光的三种光波特性曲线逐渐趋于平缓。注入电流将会直接影响到SOA的载流子浓度,以此对探测光的输出产生影响,注入电流越大,探测光的频率漂移越远。     

外部光注入混沌激光器产生超宽带微波信号的研究

利用外部光注入混沌激光器产生了完全符合美国联邦通信委员会关于室内无线通信频谱限定的超宽带(UWB)微波信号.基于外部光注入光反馈半导体激光器的速率方程组,理论研究了外部及内部参量对半导体激光器输出混沌UWB脉冲信号的影响.研究表明,UWB信号的-10 dB带宽随着光注入强度、注入失谐量以及线宽增强因子的增大而增大,随着激光器偏置电流的增大而减小.同时,UWB信号的中心频率在5–8 GHz范围内变化.在实验中,通过设定其他参量和调节光注入强度,得到中心频率及带宽可调谐的混沌UWB微波信号,传输速率达到500 Mbit/s.实验结果与理论分析相符合. 关键词： 半导体激光器 混沌激光 光生微波技术 超宽带信号     

20-Gb/s and Higher Bit Rate Optical Wavelength Conversion for RZ-DPSK Signal Based on Four-Wave Mixing in Semiconductor Optical Amplifier

We investigate 20 Gb/s wavelength conversion for return-to-zero differential phase-shift keying (RZ-DPSK) signal using four-wave mixing (FWM) in a semiconductor optical amplifier (SOA). We show that the 10-Gb/s RZ-DPSK signal-to-pump ratio increases up to -0.286 dB with Q factor improvement of 1.663 dB for increasing the cascadeability of optical networks. The effect of variation in bandwidth for an ideal dual-arm Mach-Zehnder interferometer (MZI) is illustrated. For different bit rates, the converted power signal is investigated with increase in signal input power. We show that the quality of converted signal is best before the saturation of SOA. The dependence of four-wave mixing (FWM) efficiency and converted signal power with signal input power is also studied, and it is found that FWM efficiency decreases with increase in signal input power.

The impact of signal-to-pump power ratio, unsaturated amplifier gain, and pump power is further optimized with minimum Q factor penalty for 10-Gb/s and 20-Gb/s bit rate. We show that converted signal power increases up to power saturation level and then starts decreasing. We also show that with higher bit rate, we have a wide range of choices for pump power signal. We further investigate the quality of converted signal at 10 Gb/s, which shows an improvement over signal input power. Finally, the increase in transmission distance after wavelength conversion is investigated.     

20-Gb/s and Higher Bit Rate Optical Wavelength Conversion for RZ-DPSK Signal Based on Four-Wave Mixing in Semiconductor Optical Amplifier

Abstract

We investigate 20 Gb/s wavelength conversion for return-to-zero differential phase-shift keying (RZ-DPSK) signal using four-wave mixing (FWM) in a semiconductor optical amplifier (SOA). We show that the 10-Gb/s RZ-DPSK signal-to-pump ratio increases up to ?0.286 dB with Q factor improvement of 1.663 dB for increasing the cascadeability of optical networks. The effect of variation in bandwidth for an ideal dual-arm Mach-Zehnder interferometer (MZI) is illustrated. For different bit rates, the converted power signal is investigated with increase in signal input power. We show that the quality of converted signal is best before the saturation of SOA. The dependence of four-wave mixing (FWM) efficiency and converted signal power with signal input power is also studied, and it is found that FWM efficiency decreases with increase in signal input power.

The impact of signal-to–pump power ratio, unsaturated amplifier gain, and pump power is further optimized with minimum Q factor penalty for 10-Gb/s and 20-Gb/s bit rate. We show that converted signal power increases up to power saturation level and then starts decreasing. We also show that with higher bit rate, we have a wide range of choices for pump power signal. We further investigate the quality of converted signal at 10 Gb/s, which shows an improvement over signal input power. Finally, the increase in transmission distance after wavelength conversion is investigated.     

Characteristics of the Wavelength Converted Signal in Wavelength Conversion Based on Cross-Gain Modulation

An analytical theory describing the frequency chirp characteristics of the wavelength converted signal in wavelength conversion based on cross-gain modulation (XGM) in semiconductor optical amplifier (SOA) is derived. By computation, we can see that low input pump power, high probe power, small line-width enhancement factor and low unsaturated single-pass gain of the SOA are favorable for reducing the frequency chirp of the wavelength converted signal. The analytical results have significance in understanding and designing wavelength converters.     

基于半导体光放大器交叉增益调制(SOA-XGM)波长变换器仿真研究

本文在PTDS(Photonic Transimission Design Suite)软件仿真平台上对基于半导体光放大器交叉增益调制(SOA-XGM)的波长变换器的变换特性作了仿真实验研究,仿真并分析了输入信号光功率、输入探测光功率、偏置电流和SOA的结构参量等因素对变换信号的消光比(ER)、Q值及误码率(BER)的影响关系.研究结果对优化设计SOA-XGM波长变换器有一定的参考价值.     

基于单端耦合SOA的波长转换器啁啾特性分析

提出了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, 并针对这种结构建立了动态理论模型, 以这个模型为基础分析了泵浦光功率、探测光功率、输出消光比、输入消光比对转换后信号啁啾的影响. 结果表明利用这种结构的波长转换器实现波长转换, 在提高输出消光比的同时也降低了转换光的啁啾, 较传统的波长转换器是一种改进.     

多电极半导体光放大器对增益特性的改善

提出了采用多电极实现电流非均匀注入来改变半导体光放大器(SOA)内部的载流子分布,从而改变其增益饱和特性的一种新的方案.用SOA分段模型的计算结果表明,与单电极均匀注入电流的SOA 相比,在同样的总注入电流下,对一个两电极SOA采用前面小后面大的非均匀电流注入,可以提高饱和输出功率和饱和输入功率.而采用前面大后面小的电流注入方式,则将使SOA更容易发生饱和,不仅饱和输出功率与饱和输入功率减小,而且增益谱在饱和后的压缩程度加大,增益谱压缩的对称性提高.对多电极SOA,可以方便灵活地调节各节之间的长度比和注入电流比来满足不同的应用要求.     

集成双波导半导体光放大器光开关实现波长转换的理论研究

建立了基于集成双波导半导体光放大器的光开关(ITG-SOA-Switch)的理论分析模型.与半导体光放大器(SOA)的特性相比较表明，由于ITG-SOA-Switch合并了多种物理效应，故其静态增益饱和曲线在饱和功率点附近具有大幅度陡峭下降的独特性质.理论分析和10 Gbit/s波长转换模拟结果显示，恰当地选择输入抽运光的功率范围，ITG-SOA-Switch波长转换器输出转换光的消光比特性较之输入抽运光会有显著的改善. 关键词： 波长转换 半导体光放大器 集成双波导半导体光放大器 光开关     

Generation and transmission simulation of 60 G millimeter-wave by using semiconductor optical amplifiers for radio-over-fiber systems

A novel method of the millimeter-wave (MMW) generation is proposed for Radio-over-fiber systems with low phase noise by using semiconductor optical amplifiers (SOAs). The simulation results show that the method is correct. When a pump light and a signal light are input into the SOA, the converted light induced by four-wave mixing (FWM) effect is generated. The optical MMW is generated between the signal light and converted light after filtering the pump light. The electrical MMW is obtained by beating the signal light and converted light via a photo-detector. The phase noise of the system is low because the phase difference between the signal light and converted light is stable for the FWM effect. The power of MMW is increased with the increase of the pump light power and the pump current of the SOA, is decreased with the increase of the polarization azimuths of the pump light.