Inverse design of a binary waveguide crossing by the particle swarm optimization algorithm

Abstract

This paper describes the inverse design of the particle swarm optimization algorithm combined with the three-dimensional finite-difference time-domain simulation to design a waveguide crossing that resembles a binary code. The device consists of 15 x 15 air holes in a 220-nm silicon slab on a 3-mu m-thick SiO2 substrate with one input port and three output waveguide ports. The designed device has a small footprint of 4 mu m(2) and a short simulation time of 1.7 h. In the wavelength range of 1.5-1.6 mu m, the device has insertion loss IL < 0.85 dB and crosstalk XT < -14.5 dB. This device tolerates air hole-position disordering of eta(p) = 23%, and hole-radius disordering of eta = 35%, so it is appropriate to use in the complementary metal-oxide-semiconductor fabrication process. The paper also proposes integrated interconnections that contain 2 x 2 waveguide crossings and have IL < 2.9 dB and XT < -13 dB, and 3 x 3 waveguide crossings that have IL < 5 and XT < -12.5 dB.