O-band and C-band dual-polarization SMF-28 edge coupler with SiON taper cladding based on silicon nitride platform

Optical communication is progressing towards low power consumption and lightweight solutions, necessitating the integration of multispectral output capabilities within a single optical module. We demonstrate a SiN photonic platform-based edge coupler for a standard single mode fiber (SMF) that enables operation in both the O-band and C-band simultaneously. The device is composed of a multi-segment SiN inverse taper and SiON taper cladding with specific refractive index. The measured edge coupler exhibits a coupling loss of less than 1 dB/facet, 0.5 dB bandwidth exceeding 100 nm from 1260 nm to 1360 nm; and a coupling loss of less than 2 dB/facet, 1 dB bandwidth exceeding 100 nm from 1500 nm to 1600 nm. Furthermore, the polarization dependent loss (PDL) remained less than 0.3 dB throughout the measurement range.