Demonstration of polarization-insensitive optical filters on silicon photonics platform

We experimentally demonstrate a polarization-insensitive optical filter (PIOF) using polarization rotator-splitters (PRSs) and microring resonators (MRRs) on the silicon-on-insulator (SOI) platform with complementary metal-oxide-semiconductor (CMOS) compatible fabrication process. The PRS consists of a tapered-rib waveguide and an asymmetrical directional coupler (ADC), which realize the polarization rotation and splitting, to ensure the connected MRRs-based optical filter operating at one desired polarization when light with different polarizations are launched into the device. The measured results show that the optical transmission spectra of the device are identical for TE and TM polarization input. The box-like filtering spectra are also achieved with a 3-dB bandwidth of similar to 0.15 nm and a high extinction ratio (ER) over 30 dB. (C) 2022 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement

Automated summary

In this study, a polarization-insensitive optical filter is demonstrated using polarization rotator-splitters and microring resonators on the silicon-on-insulator platform. The device shows identical optical transmission spectra for different polarization inputs, with a narrow bandwidth and high extinction ratio.