Performance analysis of automatic feedback control for multiple ...

We study the performance of automatic bias control for three bias voltages in optical quadrature phase-shift keying modulator. The interaction between multiple bias controls for two Mach-Zehnder modulators' (MZMs') bias voltages and a Mach-Zehnder interferometer's (MZI's) bias voltage is analyzed theoretically. The condition for achieving global extremum of the monitored optical power with two MZMs' bias voltages at the null transmission points is also studied by numerical simulations. The resul