Abstract: The advantages of all-opticalization with its fast transmission processing have become the current research hotspot. Among them, all-optical switches play an important role in all-optolight. In this paper, the energy band of photonic crystal structure is calculated by plane wave expansion method and super-cell technology, and the forbidden band characteristics are analyzed. Through the analysis of the energy band characteristics of several photonic crystals, the design research of all-optical switch based on tetragonal crystal structures is determined. Based on the tetragonal system structure, the 15 all-optical switch structure with waveguide and cavity coupling is designed. The time domain finite difference method is used to simulate the electromagnetic field distribution map. On the basis of this, the structure was optimized and the performance of the switch was slightly improved. By studying the forbidden band characteristics of photonic crystals and analyzing the simulation results of all-optical switches, it can be determined that the nonlinear Kerr effect based on photonic crystals can design an all-optical switch structure with excellent switching performance and reduce the size and reaction time of all-optical switch.

Key words: all-optical switch, photonic crystal, Kerr effect, plane wave expansion method, time domain finite difference method