为实现马赫-曾德尔调制器(MZM)任意偏置工作点的稳定控制, 提出了一种基于平均光功率斜率值和余切值的复合控制算法, 实现了利用FPGA技术的工作点稳定控制.首先分析了MZM偏置点稳定控制的必要性, 然后研究了控制算法的理论基础, 并在Matlab平台上进行了数学仿真验证, 最后搭建了MZM偏置工作点稳定控制系统.当激光器的输出光功率为5 dBm, MZM半波电压为4.2 V, 插入损耗3 dB, 输入脉冲为方波信号, 1 Gbps和1Mbps通信速率下, 1小时内MZM输出光信号的平均功率波动小于±5%.实验结果表明, 该方案实现了MZM任意偏置工作点的稳定控制, 有效的提高了MZM在光通信中的可靠性.

A control algorithm to achieve working bias stability for Mach-Zehnder Modulator (MZM) is proposed. Its utilize first-order and cotangent value of Average Optical Power (AOP) with FPGA technique. Firstly, we describe the reason for stabilizing the MZM at the common point. Then, control theories for keeping the bias point at different working point are studied by numerical simulation. At last, arbitrary working point control system is built. Experiment results indicate that, the fluctuation of output average optical power is less than ±5% (within one hour) under the condition of 5 dBm laser output power (1 550 nm), 4.2 V half-wave voltage, 3 dB insertion loss and 1Gbps/1Mbps speed. The system has the ability to maintain the bias at any point in the optical power curve and improved the reliability of MZM in optical communication.