A variable step perturb and observe(P&O) algorithm is proposed to realize the automatic bias control of Mach-Zehnder(MZ) modulator. A weak sinusoidal disturbance signal is added to the bias input port of the EOM. The control system based on the principle of phase-locked amplification provides the foundation for the algorithm. The simulation results of variable step and fixed step algorithms show the superiority of variable step algorithm in rapidity and accuracy. The step size of the algorithm is related to the slope, and the difficulty of parameter adjustment is greatly reduced. The operating point can be automatically stabilized at ±Quad points without the initial bias sweep. The experiments show that the drift in one hour of the system with bias control is 88.9% lower than that of the system without bias control.

中文翻译：

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基于变步长P&O算法的MZ调制器偏置控制系统

为了实现Mach-Zehnder(MZ)调制器的自动偏置控制，提出了一种变步长扰动观察(P&O)算法。微弱的正弦干扰信号被添加到 EOM 的偏置输入端口。基于锁相放大原理的控制系统为算法提供了基础。变步长和定步长算法的仿真结果表明了变步长算法在快速性和准确性方面的优越性。算法的步长与斜率有关，大大降低了参数调整的难度。无需初始偏置扫描，工作点可自动稳定在 ±Quad 点。实验表明，有偏置控制的系统在1小时内的漂移比没有偏置控制的系统低88.9%。