Improved 2 × 2 Mach-Zehnder switching using coupled-resonator photonic-crystal nanobeams.

Design and simulation results are presented for an on-chip 2×2 Mach-Zehnder-based optical switch where each arm of the interferometer is composed of a coupled-resonator optical waveguide. The individual resonators are one-dimensional photonic crystal nanobeam cavities, and switching occurs through thermally induced changes in the refractive index of the silicon structure using integrated heating pads. The performance of the coupled-resonator device is directly compared to its single resonator counterpart, and significant improvement is found in the bar-state CT metric.