On-Chip Silicon TE-Pass Polarizer Based on Asymmetrical Directional Couplers

An on-chip silicon TE-pass polarizer is proposed and demonstrated. The proposed polarizer is realized by asymmetrical directional couplers assisted with sharp bending and tapered waveguides. The TM
₀
mode is converted into TM
₁
mode through the asymmetrical directional coupler and then filtered out by the bending and taper, while TE
₀
mode goes through with negligible coupling due to the phase mismatch. The measured extinction ratio at central wavelength is 29.8 dB, while the -15 dB bandwidth is >80 nm.