| In recent years,due to the rapid growth of network communication traffic transmission efficiency,the optical communication system based on the traditional optical-electrical-optical conversion mode has encountered problems such as high power consumption and large volume,and it has been difficult to meet the bandwidth and business requirements of contemporary information networks.efficiency needs,etc.The emergence of all-optical switching can directly complete the information conversion between optical signals,and has the advantages of low power consumption,large transmission bandwidth,high speed,and high interconnection density.Optical switches are the basic core part of optical communication systems,and optical switch chips with low loss and fast switching are indispensable in the future development.This paper first studies the characteristics and phase transition principle of the phase change material VO2and the chalcogenide compound GST alloy,and chooses the non-volatile chalcogenide compound GSST as the silicon-based mixed material,and introduces the basic principle and performance of the optical switch Parameters and their classification,and the research significance of the hybrid integration of silicon and phase change materials is expounded.The mode coupling theory of waveguide is analyzed,and the mode conversion between double waveguide and triple waveguide and supermode theory are discussed respectively.The mode coupling between waveguides is studied mathematically,and the theoretical basis of the three-dimensional finite-difference time-domain method is introduced.Secondly,an optical switch based on a 1×1 periodic structure of phase change material is designed.When the phase state of the phase change material in the nano-columnar photonic crystal structure in the silicon waveguide is amorphous,in TE mode,the device The output power of the device is 0.384289,the insertion loss is 4.15d B,the output power in TM mode is 0.923993,and the insertion loss is 0.34d B;when the phase state of the phase change material is crystalline,the output power of the device in TE mode is 0.001632,The insertion loss is 27.87dB,the output power of TM mode is 0.00082,and the insertion loss is30.86d B.Then the working principle of the directional coupler is studied,and a directional coupler based on the periodic structure of the phase change material is designed by using the mode coupling theory of the double waveguide.In the case of 5nm waveguide spacing error,the splitting ratio of the two output ports of the directional coupler is optimized from46.1:52.8 to 46.3:46.6,and the insertion loss of the device is only 0.37d B.Finally,a dual-mode 2×2 cascaded optical switch based on phase-change materials is designed.The simulation results show that:when the input light source is TE mode light,the insertion loss of the optical switch at the through end is 0.9d B,and the crosstalk is12.67d B;The insertion loss at the conduction end is 0.28d B,and the crosstalk is 14.13d B.When the input light source is TM mode light,the insertion loss of the optical switch at the through end is 0.83d B,and the crosstalk is 13.4d B;the insertion loss at the crossover end is1.47dB,and the crosstalk is 8.8dB. |
