Study On Optical Filter Based On Lithium Niobate

With the advent of the information age,people have higher demand for optoelectronic devices,such as tunable filters,biosensors,and optical frequency dressing filters.The advantages of excellent device performance,low cost,miniaturization,and easy integration have become the focus of research.Optical filters are the main components of optical communication technology.Among them,thin-film optical filters are widely used due to their lower polarization-dependent losses,high channel isolation,better thermal stability,and mature manufacturing processes.Various devices made by the ring cavity structure have also become hot research,such as filters,biosensors,logic gates,electro-optic modulators,and so on.These two types of filters provide more development space for optoelectronic devices.This paper mainly studies two types of filters,one is a multilayer film filter based on lithium niobate;the other is a resonator filter based on lithium niobate.The transmission matrix method and MATLAB software are used to study and analyze the characteristics of the two types of filters in detail.Based on this,an electro-optically tunable multilayer film filter and a high quality factor electro-optically tunable racetrack dual ring are proposed.Its spectral characteristics are studied,the main contents include:1.This paper summarizes the research status of thin film optical filter and high quality factor ring resonator at home and abroad.The basic theory of thin film optics and optical waveguide are introduced in detail.Then this paper introduces the transmission matrix theory and obtains the single-layer and multi-layer film transmission matrices,analyzes the ridge waveguide structure by using the optical waveguide mode theory and effective index method,and obtains the characteristic equation and single mode of transmission conditions.2.The transmission matrix method is used to analyze the lithium niobate / magnesium fluoride multilayer filter in theory and MATLAB simulation.The spectral characteristics of the pass band and stop band filters and the influence of the relevant parameters on the reflection spectrum are discussed.Based on the electro-optical effect of lithium niobate,the spectral response of the electro-optical tunable multilayer filter is analyzed.The multilayer filter is manufactured by magnetron sputtering and etching and its performance are analyzed.3.The ridge waveguide structure composed of air / lithium niobate / silica is analyzed by effective index method.The single-mode conditions of TE mode and TM mode are given.The ridge waveguide structure of ring waveguide resonator is designed.The transmission matrix of single ring with single waveguide and single ring with double waveguides is given by using the working principle of micro ring resonator.The racetrack dual ring resonator with thehigh quality factor based on lithium niobate is proposed and its transmission characteristics are analyzed,focusing on the influence of transmission factor,coupling factor and field attenuation coefficient on its optical spectrum characteristics.Using the electro-optical effect of lithium niobate,the racetrack dual ring resonator is discussed and analyzed and the tunable range and tuning rate of the filter are obtained.