Study On Etching Filling DBR Waveguide Grating Filter Based On SOI System

In this paper,the theory and simulation research of 1550 nm band SOI photonic chip system based on waveguide DBR grating control is carried out.Waveguide Bragg grating(WBG)is one of the key devices of Integrated Optoelectronics platform,which is widely used in optical filters,mirrors,couplers,lasers,sensors and so on.With the development of polymer waveguide,polymer waveguide Bragg grating has attracted much attention because of its low cost,easy fabrication,controllable refractive index and compatibility with any substrate.According to the Bragg condition,coupled mode theory and transfer matrix method,a fully etched tunable uniform Bragg grating band stop filter based on SOI(silicon on insulator)is proposed.Then,the finite difference time domain method(FDTD)is used to simulate and study the influence of grating parameters such as grating period and duty cycle,grating period number and refractive index on the filtering characteristics.By changing different parameters,the filtering wavelength can be adjusted in real time and non real time.At the same time,in order to further improve the filtering effect,by increasing the order of the grating and filling the medium in the grating groove,a narrower filter bandwidth is achieved.Compared with the traditional grating filter,the structure has higher sensitivity in adjusting the filtering wavelength.In addition,compared with shallow etching,full etching is easier to realize and control,and ensures a narrow filtering bandwidth under full etching.Finally,the research on the Bragg uniform grating filter with shallow etching is the same as that with full etching.It is hoped that the problem of serious nonresonant wavelength loss of high-order grating filter under full etching can be reduced under shallow etching.At the same time,the influence of etching depth on the filtering characteristics is studied.Finally,compared with the full-etched grating filter,the bandwidth is narrower and the loss of non-resonant wavelength is reduced in the high-order grating.