Photonic crystal based on mott phase change material as all-optical bandgap switch and composite logic gate

Abstract We propose a composite photonic crystal based on phase change material to realize the photonic bandgap dependent all-optical switch in the mid-near infrared band. The demonstrated photonic crystal all-optical switch is built on the surface of integrated silicon waveguide on standard SOI and matched with standard CMOS lithography process. The communication light in the silicon waveguide is modulated by VO2 with Mott metal-insulator transition at near room temperature which results in the shifting of optical bandgap. The simulations based on the finite difference time domain method show that the photonic crystal device possess a modulation depth of 0.95 and an insertion loss of 1.27 dB for fundamental TM mode propagating at 1550 nm. We also discuss the influence of device length and thickness of photonic crystal on the switching performance. Moreover, the compound logic gate derived from proposed switch is also designed to provide NOT and NOR operations simultaneously for the next-generation all-optical chips. Due to the reversible phase transition process of VO2 photonic crystal, the proposed device can realize the fast state switching of light and is expected to provide some help for the research of silicon-based optical chips.