Research On New Highly Integrated Photonic Devices Using Inverse Design

In the past 70 years of informationization,integrated circuit technology based on silicon materials has made great contributions to the advancement of science and technology by continuously improving the integration.Integrated optical technology using different materials as a platform strives to miniaturize the device,which has led to nanophotonic devices.In the development of photon and electronics integration,silicon photonics is expected to achieve ultra-large capacity,ultra-high speed,low energy consumption,and low crosstalk information transmission.In order to further improve the performance of silicon-based optoelectronic devices,a new type of optoelectronic device is studied in this thesis under the idea of inverse design.The main research contents and results are as follows:?1?A new silicon-based microcavity optomechanical system that can be used as a source of optical chaos is designed.The two-dimensional optomechanical cavity we proposed is formed by introducing a nanomechanical double-beam resonator into a width-modulated line-defect photonic crystal cavity.This system can realize strong optical-mechanical coupling,with ultra-small effective quality and ultra-high optical quality factor.When the effective motion mass is as small as 11.3fg and the simulated optical quality factor is 5.97×10⁷,the optomechanical coupling rate g₀/2?=458kHz is achieved.?2?A tunable four-channel WDM multiplexer based on inverse design is proposed.We adopted an advanced objective-first inverse design algorithm on the silicon-on-insulator platform.With a channel spacing of 60nm and a device size of only 20.16?m²,we achieved approximately 70%transmission and less than-13dB crosstalk.At the same time,we explored the tunability of the target wavelength of the wavelength division multiplexer for change in the refractive index of the device.The finite-difference time-domain simulation shows that when the refractive index value increases,the working wavelengths of the four channels will be uniformly red-shifted.?3?A dual-channel wavelength demultiplexer based on surface plasmon polaritons is proposed.On the silver platform,for the two wavelengths of 1380nm and 1550nm,a direct binary search inverse design algorithm was used to obtain the distribution of air holes matching the design target.When the device size is 0.5?m×0.55?m,the insertion loss at the two channels are-0.67dB and-0.89d B.In addition,we also compare the optimization results for different device sizes and different cell sizes.Increasing the size of the device or reducing the size of the unit can increase the freedom of adjustment.Within a certain range,the device easily has better performance.?4?A structural color filter based on surface plasmon polaritons is proposed.The filter consists of four MIM plasma waveguides?one input waveguide and three output waveguides?and a coupling region.Aiming at the three primary colors of RGB,a direct binary inverse design algorithm was used to obtain the relative distribution of silver and air in the coupling region.In the size range of 0.5?m×0.55?m,a transmission of more than 70%was achieved,and a standard International Commission for Illumination?CIE?1931 chromaticity diagram was drawn.