Integrated polarization rotator on silicon waveguides with an asymmetric trench

We demonstrate an integrated polarization rotator with a single trench on a silicon waveguide fabricated using a single etch-step complementary metal-oxide-semiconductor (CMOS)-compatible process. The measured polarization rotation efficiency is 95 % with 0.76 dB insertion loss for a total 67-μm long and 100-nm wide asymmetric trench.