Simulation Research On Microring Kerr Optical Frequency Comb Under Heat Effect

Optical frequency comb is a new type of spectrum with a comb structure and stable existence.It can be used as a tool for many precision measurements as well as a multi-wavelength light source.Compared with other methods of generating optical frequency combs,the Kerr optical frequency comb based on the nonlinear Kerr effect of the microresonator has the advantages of wide coverage in the frequency domain,high coherence,and integrating device structure simply.In recent years,experiments for generating Kerr-frequency combs based on different materials and structures have been reported successively.At the same time,relevant theoretical researches have gradually developed,but most of them ignore the influence of thermal effects in the theoretical study.Under strong light pumping,the microcavity mode is treated as an extension of the cold cavity mode.Obviously,this does not meet the actual situation.In order to understand the effect of thermal effect on the generation process of optical frequency combs further,this dissertation simulates this generation process theoretically on the basis of T.Carmon et al.' s related thermal effect work.By introducing the phase shift caused by the thermal effect into the LLE equation so as to improve the equation,the effect of the thermal effect into the simulation analysis.Based on this method,the generation process of microcyclic Kerr optical frequency combs are analyzed for the single pump and the double pump case.The evolutions of the soliton and Kerr frequency combs with two different methods to manage the initial detuning are investigated.The flatness of the optical comb for the cases of single pump and double pump are compared and studied.The main contents and innovations of the dissertation are as follows:1.In the deep understanding of the nonlinear effects produced in the microcavity under the effect of the pump light field,the process of forming the time domain soliton and the frequency domain Kerr optical frequency comb are analyzed in detail.By quantitatively studying the characteristics of the cavity temperature change caused by the pump light field,the phase shift generated by the introduction of the thermal effect is used to modify and improve the original LLE model.2.The LLE model modified by the thermal effect passes two different treatment methods for the initial detuning,namely the fixed initial detuning and the initial detuning,for the single-pump cavity soliton and Kerr optical frequency.The evolution of the comb is simulated.From the theoretical point of view,the mechanism of soliton and Kerr frequency combs in two situations is deeply studied,and the reasons casued the differences in the results are analyzed.The process of generating Kerr optical frequency combs in microcavities is further explained.3.The simulation study of the production process of dual-pump microring Kerr optical frequency combs under the thermal effect is cartied out.It is analyzed that the double-pump power fluctuation in the time domain can also realize a function as the perturbation of the modulation instability.Therefore,the random noise added to the pump can be removed,so that the random factors generated by the soliton in the cavity and the frequency-domain Kerr comb are removed.And the resulting Kerr optical frequency comb is more stable.The simulations verify that the double pumping function can adjust the spacing of the adjacent comb teeth and the number of solitons in the control cavity of the Kerr light comb,and improve the flatness of the Kerr optical frequency comb,so that the Kerr frequency comb can be applied torelated area better.