Two-dimensional silicon photonic grating coupler with low polarization-dependent loss and high tolerance

We design and demonstrate a two-dimensional grating coupler with an elliptical-like etching pattern on the silicon-on-insulator platform. The polarization-dependent loss of the fabricated device is measured to be 0.2 dB at the C-band, lower than that of most conventional 2D GCs. The etching unit can be easily fabricated with a large tolerance of ± 10 nm and a large feature size of 310nm, which is beneficial to its manufacturing process and wide application.