【作者】 李珂；

【导师】 黄德修；

【作者基本信息】 华中科技大学 ， 光学工程， 2009， 硕士

【摘要】 半导体光放大器(SOA)有非线性系数高、增益谱宽、体积小和易于集成的优点,因此在全光信号处理领域受到了广泛的关注。差分相移键控(Differential Phase-Shift Keying, DPSK)调制方式与传统的OOK(On-Off Keying)调制方式相比,具有更高的非线性容限,结合干涉仪解调和平衡探测可以明显提高接收机的灵敏度,成为高速、长距离光纤传输系统研究的热点。本文对深饱和SOA中的交叉增益压缩(Cross-Gain Compression,XGC)效应进行了理论研究,在此基础上对基于该效应的DPSK信号2R再生(Reamplifying, Reshaping)进行了再生性能的分析。本论文首先建立了包含两个偏振态的SOA理论模型,其中考虑了纵向载流子浓度的非均匀分布以及增益谱随载流子浓度的漂移,载流子加热、光谱烧孔等高阶非线性效应造成的增益压缩用增益压缩因子描述。在分析SOA静态和动态特性的基础上,分析了SOA的物理参数和外部工作条件对XGC效应整形作用的影响,如有源区长度、载流子寿命、增益压缩因子、模场限制因子、入射光功率、光波长等,结果表明XGC效应可以明显抑制振幅噪声,且通过SOA的物理参数和外部工作条件的优化设计可以实现XGC效应的增强。为了全面分析基于XGC效应的DPSK信号2R再生方案的再生性能,对SOA可能引入的相位噪声进行了详细的研究,结果表明XGC效应在抑制振幅噪声的同时,SOA引入的非线性相位噪声会使得相位出现一定程度的劣化,但是相位劣化不足以抵消XGC效应对振幅噪声的抑制作用,通过选择适当的SOA物理参数和外部工作条件,可以尽可能地抑制非线性相位噪声的产生,从而提高再生器的再生能力。总体而言,XGC效应对信号的振幅噪声有良好的抑制作用,基于该效应的DPSK信号2R再生应用达到了良好的效果。更多还原

【Abstract】 Semiconductor optical amplifier (SOA) has been widely applied in all-optical signal processing, because it has benefits of high nonlinear coefficient, wide gain spectrum, small size and can be easily integrated. Compared to conventional on-off keying(OOK) modulation, Differential phase shift keying (DPSK) behaves higher non-linear tolerance. Combined with interferometer demodulation and balanced detection, this format can significantly improve the receiver sensitivity,and therefore has attracted a great of attention especially for high-speed, long-haul transmission.In this thesis, we theoretically study the cross-gain compression (XGC) efftcet in a deeply saturated SOA,and the regeneration performance analysis of DPSK 2R regeneration program based on the XGC effect is made .In this thesis, firstly,the SOA model including the two polarization states is established, which takes into account the non-uniform distribution of the carrier density and gain spectrum shift. The gain compression caused by high-order nonlinear effects is described by gain compression factor ,such as carrier heating and spectral hole burning.Based on the analysis of static and dynamic characteristics of SOA, we have analyzed the effects of SOA’s physical parameters and the working conditions on shaping ability of the XGC effect,such as,the source region of length, carrier life, gain compression factor, field confining factor, the input light power, wavelength.It has been proved that the XGC effect can significantly restrain noises of the amplitude . The XGC effect can be enhanced through the optimum design of SOA’s physical parameters and working conditions. In order to effect a comprehensive analysis of regeneration program performance for XGC-based 2R regeneration for DPSK signals,we study the phase noise that may be introduced by the SOA during the XGC effect’s working time. The conclusion is the nonlinear phase noise introduced by the SOA makes the phase more deteriorated, but the phase deterioration can not counteract the suppression of amplitude noise contribution from the XGC effect. The nonlinear phase noise can be restrained as much as possible by choosing appropriate physical parameters of the SOA and working conditions and the regeneration ability of the regenerator can be improved. Overall, the XGC effect behaves evident performance on noise restrain ,and the application on the DPSK signal 2R regeneration achieves a good result.更多还原