Phase Shaping to Control the Performance of a Contra-Directional Grating-Assisted Coupler

We propose a method of improving the performance of a planar grating-assisted contra-directional coupler for use as a photonic switch. By means of a nonuniform Bragg grating, rapid phase jumps are introduced within the reflection spectra of coupler supermodes. This creates a reflection peak of steep slopes, flat top, and desired width. Sample numerical results are given for realistic material and device parameters. A discrete layer-peeling method is employed for the synthesis of the Bragg grating.