灵活高阶正交幅度调制矢量光信号的产生与传输分析

Generation and Transmission Analysis of Flexible High-Order Quadrature Amplitude Modulation Vector Optical Signals

灵活光发射机可根据不同应用场景需求软定义信号的调制格式,从而进一步优化光信号的传输性能。本文提出了一种基于双平行马赫-曾德尔调制器(MZM)和单MZM级联的灵活高阶正交幅度调制(QAM)光发射机方案,理论分析了圆形16QAM、4幅4相16QAM、圆形32QAM以及4幅8相32QAM光信号产生与自适应切换的原理与方法。在虚路径标识符(VPI)仿真环境下,分别验证了上述4种信号在5 Gbaud和10 Gbaud调制速率下的产生和传输性能。结果表明,通过灵活配置发射机的驱动信号(二进制或四进制)与直流偏置电压,可实现8/16/32QAM信号间的自由切换,同时,生成的上述4种信号经一定长度单模光纤传输后具有良好的信噪比。

Flexible optical transmitters can define the modulation format of a signal according to the requirements of different application scenarios,further optimizing the transmission performance of an optical signal.A flexible highorder quadrature amplitude modulation(QAM)optical transmitter scheme based on a dualparallel MachZehnder modulator(MZM)and a single MZM cascade is proposed in this paper.The principle and method of generating and adaptiveswitching circular 16QAM,fouramplitudefourphase 16QAM,circular 32QAM,and fouramplitudeeightphase 32QAM optical signals are theoretically analyzed.In the virtual path identifier(VPI)simulation environment,the generation and transmission performance of the above four signals under 5 Gbaud and 10 Gbaud modulation rates are verified.The results show that the transmitter supports free switching between 8/16/32QAM signals by configuring the drive signal(binary or quaternary)and the directcurrent bias voltage of the transmitter.Furthermore,the four generated signals have a good signaltonoise ratio after transmission through a specific length of a singlemode fiber.