Photonic Crystal Waveguide Device Design And Sensing Applications

In recent years,with the rapid development of electronic information industry,traditional semiconductor devices have been difficult to meet people’s diversified requirements for information processing,people began to look for effective solutions to the photon technology.Photonic crystal devices have many advantages,such as small size,easy integration,flexible structure and compatibility with SOI process,etc.,and have become the research hotspot in the field of photons.In this paper,a theoretical model of photonic crystal waveguide structure is established and optimized based on the coupled mode theory,and a new idea for the application of photonic crystal waveguide is provided by studying the mechanism of light wave transmission and control.The main research contents of this paper are as follows:（1）In a one-dimensional photonic crystal waveguide as the study of the basic structure,combined with the plane wave expansion method analyze the photonic band gap structure of photonic crystal,light transmission characteristics analyzed by adopting the finite difference time domain method,the concrete research of photonic crystal microcavity coupling mode theory,the mechanism of light control and transmission characteristics,for the one-dimensional photonic crystal waveguide model provides a theoretical support.（2）Two kinds of microcavities with different local modes of air and dielectric are studied.By adjusting the structure of the photonic crystal,the refractive index sensitivity of the air mode is higher than that of the dielectric mode,and the temperature sensitivity of the dielectric mode is higher than that of the air mode.Combined with the light field distribution of the steady-state electric field diagram at the resonant wavelength,the difference of the sensitivity in the microcavity under different modes is explained.The temperature and refractive index of the external environment can be calculated by the drift of the resonant peak wavelength of the two waveguides.（3）Based on the transmission characteristics of both the side-coupled and direct-coupled photonic crystal waveguides,a cascade double-channel photonic crystal waveguide is designed.The structure has only two peaks in the detection frequency band,which are the peak and the trough.The dual parameters of temperature and refractive index can be measured at the same time,and the two channels have good independence.（4）One-dimensional photonic crystal waveguide structured optical switch is designed based on temperature phase change material VO₂.The temperature sensitivity of the switch is reduced by filling SU-8 cladding in the silicon waveguide to compensate the temperature sensitivity.The switch is driven by heat and has good extinction ratio,and the resonant peak wavelength of the microcavity does not drift when the switch is driven by heat.At the same time,a novel cascade waveguide is proposed to optimize the switch structure,which is expected to realize the overheating protection mechanism in the optical chip.