Box-like filter response and expansion of FSR by vertically triple coupled microring resonator filter

摘要

Vertically coupled microring resonator filters are promising to the Add/Drop wavelength filter due to their functionality, compactness, and the possibility of dense integration. However, the tailoring of filter response shape is required to improve the performance, such as the flatness of pass band, cross talk, and FSR. The series coupled microring resonator is one of solution. We designed and fabricated triple coupled microring resonator Add/Drop filters with stacked configuration. The box-like filter response with flat pass band was successfully obtained and the FSR was expanded to 25.8 nm owing to the Vernier effect.