Research On Simulation Algorithm Of Optical Devices Based On Free-form

Compared with the traditional bulk optical circuits,integrated optical circuits have the advantages on multifunction,high integration,miniaturization and so on.The stability and reliability brought by integration make integrated optical chip become an important direction.However,due to the less adjustable parameters,the conventional components of integrated photon devices usually have larger footprints,So the simulation of photon devices based on free form was born.With development of more and more algorithms,we can use enough parameters in a very small space to achieve a variety of small and efficient optical devices,which provides the possibility for the future integration of high-density photonic devices.In the third chapter,we use the objective-first method to realize and solve a two-dimensional single channel to multi-channel universal arbitrary mode converter.We simulate the conversion of the fundamental mode to the second-order mode for single channel to single channel,single channel to double channels,and single channel to three channels,and the conversion efficiency can be larger than 98%.Our designs are all within 120 * 120 grid points,each of which is square with side length of.Finally,we test the conversion simulation effect of single channel to single channel under different conditions,and the efficiency can be higher than 85%.In Chapter 4,we simulate a polarization beam splitter(PBS)with a binar y pixel structure.Compared with the traditional DBS algorithm,which is sensitive to the initial random pattern,we optimize it by using the genetic algorithm and simulated annealing algorithm,respectively.The transmissivity of PBS sim ulated by genetic algorithm on 1550 nm TM mode is 0.344,with an extinction ratio of 11.85 d B,The transmissivity of TE mode is 0.17,with an extinction ra tio of 6.24 d B.The transmissivity of 1550 nm TM mode of PBS simulated by si mulated annealing is 0.402,with an extinction ratio of 11.2d B,The transmissi vity of 1550 nm TE mode is 0.263,with an extinction ratio of 6.02 d B.Com pared with the structure optimized by genetic algorithm,the transmissivity is i mproved,but its extinction ratio is approximately the same.The time efficienc y of simulated annealing is 1/3 less than that of genetic algorithm.Considering the influence on the initial random pattern,for this structure using the simulat ed annealing and DBS algorithm,the priority is about the same,followed by t hat using the genetic algorithm.In this paper,we design and simulate two different ways for investigation,and analyze and compare the results,Our approach may provide new ideas for future work.