Miniaturized Bragg-grating couplers for SiN-photonic crystal slabs

Opt Express. 2015 Apr 20;23(8):9803-11. doi: 10.1364/OE.23.009803.

Abstract

We report on an experimental and theoretical investigation of an integrated Bragg-like grating coupler for near-vertical scattering of light from photonic crystal waveguides with an ultra-small footprint of a few lattice constants only. Using frequency-resolved measurements, we find the directional properties of the scattered radiation and prove that the coupler shows a good performance over the complete photonic bandgap. The results compare well to analytical considerations regarding 1d-scattering phenomena as well as to FDTD simulations.