Optimization of tunable silicon compatible microring filters

Abstract

Microring resonators can be used as pass-band filters for wavelength division demultiplexing in electronic-photonic integrated circuits for applications such as analog-to-digital converters (ADCs). For high quality signal transmission, the resonant frequency of the filter has to be held at certain value to allow minimum timing errors in the sampling of the signal. Thermal tuning is used to compensate for any fabrication errors or environmental temperature fluctuations that might lead to shift in the resonant frequency. With the optimized heater design and the proper closed feedback temperature control circuit, the rings have very efficient on-chip thermal control to maintain the resonant frequency within 280 MHz.