SOI-based bandwidth-tunable grating filter with a large tuning range

摘要

A polarization-independent bandwidth-tunable filter with a large tuning range using binary blazed grating based on silicon on insulator (SOI) is proposed and designed. This grating filter can show different spectral bandwidths under different angles of incidence. When the angles of incidence ranges from 42° to 48°, the grating functions as an ultra-narrow filter, and its minimal full width at half-maximum (FWHM) is about 0.6nm. More importantly, its resonant wavelength shifts linearly with respect to changes in the angle of incidence, with a slope of 4.5nm/°, regardless of the polarization states. When the angle of incidence is changed to 10°, it turns into a broadband filter, which has a reflectivity of over 99% in the wavelength range of 1510nm~1600nm for both polarization states.