High-efficiency broadband out-of-plane fiber-to-polymer waveguide grating coupler

Polymer photonics is receiving significant attention due to its potential for a wide range of integrated photonic applications and wide wavelength transparency. Wafer-scale testing is challenging due to low-index contrast in polymer waveguides. In this Letter, we demonstrate an amorphous silicon based out-of-plane polymer waveguide grating coupler. Simulations predict a maximum efficiency of -1.13 dB, with a 1 dB bandwidth of 95 nm over the C-L-band. Experimentally measured peak coupling efficiency between a single-mode optical fiber and polymer waveguide is -2.15 dB per coupler with a 1 and 3 dB bandwidth of 49 and 89 nm, respectively.