A Mach-Zehnder Modulator Bias Controller Based on OMA and Average Power Monitoring

We demonstrate an integrated circuit (IC) implemented in 28-nm CMOS technology for Mach-Zehnder modulator (MZM) bias control. Our circuit determines the optimal MZM bias voltage that provides the largest optical modulation amplitude and maintains this bias voltage by monitoring the average modulated power. The controller IC consists of digital-to-analog converter, analog-to-digital converter, trans-impedance amplifier, power detector, track-and-hold circuit, comparator, and digital controller, all of which are integrated in a single chip. With small power consumption and chip area, our approach should be applicable for future photonic electronic integrated circuits based on the Si platform.