基于单PD直接检测Twin-SSB-QPSK信号的光纤通信系统

Single photodiode-based direct detection for Twin-SSB-QPSK signal in optical fiber communication systems

针对孪生单边带正交相移键控(Twin-SSB-QPSK)信号在光传输过程中的高成本问题,提出了一种在接收端采用单光电探测器(PD)直接检测Twin-SSB-QPSK信号的光纤通信系统。在接收端不需要采用光带通滤波器(OBPF)对Twin-SSB-QPSK信号的两路光单边带信号进行分离,而是利用直接检测的拍频效应,通过单PD直接检测孪生的两路光单边带QPSK信号产生相干叠加的单路16阶正交幅度调制(16QAM)信号。仿真演示了两路56 Gbit/s的QPSK信号叠加为一路112 Gbit/s的16QAM信号,并与传统的单路16QAM信号传输方案进行了仿真对比。仿真结果表明,该方案在降低系统器件要求和部署成本的同时并没有带来额外的功率代价。

To address the high-cost issue of twin single sideband quadrature phase shift keying(Twin-SSB-QPSK)signals in optical transmission,a optical fiber communication system was proposed,in which a single photodetector(PD)was employed at the receiver to directly detect the Twin-SSB-QPSK signals.At the receiver end,optical bandpass filter(OBPF)was not required to separate the two optical single sideband signals of the Twin-SSB-QPSK signal.Instead,the heterodyne effect of direct detection was utilized,allowing a single PD to directly detect the coherent superposition of the twin two optical single sideband QPSK signals,resulting in a single 16-ary quadrature amplitude modulation(16QAM)signal.Simulations demonstrated that two 56 Gbit/s QPSK signals were combined into a single 112 Gbit/s 16QAM signal and then compared with the traditional single 16QAM signal transmission scheme.The simulation results indicate that the proposed scheme does not introduce additional power penalties while reducing the system device requirements and deployment costs.