Topology Optimization for Photonic Crystal Waveguide with Wide and Flat Bandwidths in Ultra-Fast All-Optical Switch (PC-SMZ)

Abstract

Topology optimization has been used to design intersections and bends in two-dimensional photonic crystal slab waveguides. We have experimentally confirmed that the optimized intersection displays high transmittance with low crosstalk for the straightforward beam line. IntroductionTwo-dimensional (2D) photonic crystal (PC) slab waveguides (WGs) are attractive candidates for novel applications in a miniaturized photonic integrated circuit. We have already demonstrated a symmetric Mach-Zehnder type all-optical switch based on the 2DPC WG (PC-SMZ) [1]. To create a PC-SMZ-based ultra-fast photonic logic device, one of the priority subjects is to develop a new design method, i.e., topology optimization (TO) [2, 3] of 2DPC WGs with wide/flat bandwidth, high transmittance and low reflectivity for improving switching performance. In this paper, we report on TO designs of 2DPC WGs exhibiting intersections and bends with wide and flat bandwidths in the PC-SMZ.