任意偏置点的电光调制器自动偏置控制方法

An automatic bias control method applied to all bias points of electro-optic modulator

为了实现对双电极马赫-曾德尔电光调制器任意直流偏置点的自动偏置控制,采用在闭环控制基础上,引入一个可调移相器使不同直流偏置点处误差信号相同的方法,理论分析了可调移相器相移量与直流偏置相位的关系,仿真得到对于不同偏置点,当调制器直流偏置相位漂移达-0.15rad～0.08rad,移相器引入附加相位漂移-0.55rad～0.55rad时,经偏置控制后相位漂移被限制在-3.0×10-4rad～1.7×10-4rad范围内。结果表明,该方法有效实现了对电光调制器任意直流偏置点的自动偏置控制。

To control the bias of dual-electrode Mach-Zehnder electro-optic modulators automatically,an adjustable phase shifter was introduced based on closed-loop control method so that the error signal remained the same at different direct-current（DC）bias points.The relationship between phase shift of the adjustable shifter and DC bias phase was derived by theoretical analysis.Simulation showed that,the drift of DC bias phase in the range of-0.15rad～0.08rad with the added phase drift caused by the phase shifter in the range of-0.55rad～0.55rad could be suppressed to-3.0×10^-4rad～1.7×10^-4rad at different DC bias points.The results show that the automatic bias control of an electro-optic modulator at any DC bias points is effectively achieved.