Coarse-Fine Control of Dual-Tuner Mach-Zehnder Interferometer using Identical Low-Resolution DACs

We present a novel approach for achieving coarse-fine control of two thermo-optic phase shifters in a dual-tuner Mach-Zehnder interferometer-based photonic switch. We demonstrate the concept in a fabricated silicon switch containing thermo-optic phase tuners driven from identical monolithically integrated low-resolution digital-to-analog converters.