Research On The Generation And Characteristics Of Dissipative Kerr Solitons Based On Resonators With Saturable Absorbers

The emergence of optical frequency comb technology promotes the development of precision measurement,optical communication,and other fields,so people pay more attention to the generation of optical frequency comb and the optimization of its performance.The optical frequency comb based on nonlinear Kerr effects in the resonant cavity becomes a research hotspot due to its wide operating range,simple experimental configuration,and high optical frequency comb performance.However,the research on the generation of dissipative Kerr solitons corresponding to Kerr optical frequency comb and the improvement of the soliton performances in the resonator still face many challenges,such as difficulties in self starting,instability caused by thermal effects,and low conversion efficiency of pump light to solitons.Based on this context,this thesis conducts the research on the generation principle,evolution mechanism,and related properties of dissipative Kerr solitons in a resonator containing the saturable absorber.The main research contents are as follows:1.The generation of dissipative Kerr solitons in a fiber ring resonator based on the saturable absorber is explored.The Ikeda diagram model composed of the typical nonlinear Schrodinger equation and the transmission conditions is proposed to explore the evolution of the optical field and the performances of the generated dissipative Kerr solitons in the fiber ring resonator containing the fast saturable absorber.The simulation results show that there is the generation of the stable dissipative Kerr solitons in the fiber ring resonator containing a fast saturable absorber,and the performances of the dissipative Kerr solitons can be further optimized by controlling the parameters of the fast saturable absorber.This means that,in addition to the pump power and the detuning value,saturable absorbers can become new degrees of freedom for controlling the generation of solitons and optimizing the performances of solitons.2.The generation of dissipative Kerr solitons in a microcavity based on the saturable absorber is explored and the linear Fabry-Perot cavity is used as the microcavity.Under the frequency tuning scheme,the Lujiato-Lefever-Equation model is used to explore the evolution of the optical field in the Fabry Perot cavity,and the characteristics of dissipative Kerr solitons in the cavity with or without the saturable absorber are compared.The simulation results show that the frequency scanning scheme can overcome the thermal effect in the microcavity and promote the generation of stable dissipative Kerr solitons.Although the introduction of the slow saturable absorber into the microcavity increases the threshold value of the pump power because of its additional loss,the generated solitons can have narrower time width,higher peak power,and higher energy.This means that the introduction of the saturable absorber can promote the generation of high-performance dissipative Kerr solitons,and the emitted optical pulses can become high-quality light sources in integrated optics.3.In addition to the saturable absorber,the effects of other factors on the properties of dissipative Kerr solitons are also the focus of this thesis.Based on the above simulation model,the influence of different factors on the characteristics of dissipative Kerr solitons in the resonator is summarized through the control variable method.The factors include the pump light,the initial conditions,the high nonlinearity,and the loss.The effects of these factors on soliton characteristics can be summarized as follows: the form of the pump light determines the threshold power for the soliton generation and the pump-to-soliton conversion efficiency,the initial condition affects the number of solitons,high nonlinearity can lead to the coexistence of different nonlinear states in the cavity,and the loss can lead to the generation of solitons with different orders.This means that soliton pulses with specific properties can be generated by controlling different factors in the resonant cavity,which can provide the theoretical guidance for experiments.