Bandwidth-tunable silicon nitride microring resonators

Abstract

We designed a reconfigurable dual-interferometer coupled silicon nitride microring resonator. By tuning the integrated heater on interferometer’s arms, the “critical coupling” bandwidth of resonant mode is continuously adjustable whose quality factor varies from 7.9 × 104 to 1.9 × 105 with the extinction ratio keeping higher than 25 dB. Also a variety of coupling spanning from “under-coupling” to “over-coupling” were achieved, showing the ability to tune the quality factor from 6.0 × 103 to 2.3 × 105. Our design can provide an adjustable filtering method on silicon nitride photonic chip and contribute to optimize the nonlinear process for quantum photonics and all-optical signal processing.