Performance of 2D-Grating couplers designed through full 3D-FDTD numerical simulations

By bridging the dimensional gap between fiber mode and Silicon On Insulator (SOI) layer thickness, 1D and 2D-Grating couplers (GCs) represent promising solutions to the challenge of coupling light into silicon photonics circuits. Considerable work has been done over the last decade towards optimization 1D-GCs, that nevertheless exhibit a very strong sensitivity to the input polarisation state of the fiber, which makes them unsuitable for many inter-system coupling applications. Recently, a new strategy based on a full 3D-FDTD (finite difference time domain) calculations has been proposed to describe 2D-GC operation, and optimize their performance.