Research On Microring Resonator For Generating Kerr Optical Frequency Comb

In recent years,with the development of integrated optoelectronic technology,microring resonators have attracted widespread attention.It has the advantages of simple structure,small occupation area,high integration and great application potential.Thanks to the development of advanced manufacturing technology and the outstanding nonlinear characteristics of the microring,the microcavity optical frequency comb technology has become a research hotspot.By designing and preparing microring resonators with high quality factor,low loss and high Kerr nonlinear effect,the excitation of the optical frequency comb can be further realized.In this paper,the design and research work of microring resonators that can generate optical frequency combs are carried out,and the generation mechanism,theoretical model and test method of microcavity optical frequency combs are deeply explored,and their applications in RF-related fields are briefly introduced.The specific work content is divided into the following aspects:(1)Firstly,the generation principle of microcavity optical frequency comb is analyzed in detail,and deeply study the generation process of the sideband comb spectrum.Secondly,the transmission process of optical pulses in the fiber is studied according to the nonlinear Schrodinger Equation.Then,the Lugiato-Lefever Equation(LLE)which can describe the variation of the cavity field in the microring is obtained by combining the Equation with the boundary conditions.Then,the generation of Kerr optical frequency comb is studied by establishing a model.The simulation results show that the transmission shape of pulsed light is changed due to the combined action of dispersion and nonlinear effect.On this basis,the parameters such as the size of the microring and nonlinearity coefficients are further optimized,and the program is rewritten using the step-by-step Fourier algorithm.Finally,a series of new spectral components are obtained by simulation.(2)The microring resonator used to generate optical frequency comb is studied in depth and the corresponding test scheme is developed.According to the working principle of the microring resonator and the requirements for generating Kerr optical frequency combs,the material structure,quality factor(Q),loss and dispersion of the microring resonator are effectively simulated and designed.The phase matching condition of four wave mixing(FWM)effect is explored,combined with important integration processes,the silicon dioxide microring resonator is designed and fabricated.Then,according to relevant theories and simulation parameters,a test scheme of the transmission spectrum of the microring was developed,and the wavelength scanning method was chosen to test and analyze the transmission spectrum of the microring.(3)According to the measured half-wave full width of the transmission spectrum of the microring and the wavelength value at the corresponding resonance,the Q value of the physical microring can be estimated to the order of 10~6,which means that it can accumulate more energy in the microring,which is more beneficial to the generation of optical frequency comb.Then,a test platform was built to conduct the optical frequency comb excitation experiment by using a series of nonlinear effects balanced in the microring resonator.In addition,the optical frequency comb has a coherent frequency sequence,can provide a large number of wavelength channels,and can replace the wide spectrum light source to combine with the RF photonics.On this basis,the experimental scheme of radio frequency photonic filters is discussed,and its application in RF photonics is studied.