Studies On Mode-locked Fiber Laser With High Repetition Rate And Low Timing Jitter

With the rapid development of digital information society,analog-to-digital converter(ADC),the bridge between the analog world and the digital society,becomes more and more important.Sampling is a vital part of ADC,which has a great influence on the performance of ADC.Sampling the analog signals with ultrashort optical pulse could overcome the bottlenecks of electrical technology and improve the performance of ADC.However,the femtosecond pulse source with high repetition rate and low timing jitter is still under study to meet the requirement of optical sampling.Aiming at the research status of the passively mode-locked fiber laser with high repetition rate and low timing jitter,this paper studies the timing jitter in theoretical analysis and MATLAB numerical simulation.Furthermore,semiconductor saturable absorber mirror(SESAM)mode-locked fiber lasers with a fundamental repetition rate up to 1 GHz are demonstrated.The key research contents and innovations of this paper are summarized as follows:1.The application prospect of passively mode-locked fiber lasers with high repetition rate and low timing jitter is introduced and the research status at home and aboard in repetition rate and timing jitter is also summarized.2.Based on the nonlinear Schrodinger equation(NLSE),the characteristics of fiber including dispersion,loss,self-phase modulation(SPM)and gain are analyzed theoretically.With the amplified spontaneous emission(ASE)noise added to the NLSE,the equation is solved by the split-step Fourier transform method and the MATLAB numerical simulation model of fiber is constructed.3.The numerical model of the fiber laser is established by reasonable analysis of each component of the laser.Based on the numerical model,the soliton,stretch pulse,self-similar pulse and all-normal dispersion fiber laser are simulated.Meanwhile,the quantum-noise-limited timing jitter of the fiber laser is also simulated numerically.4.With the ASE noise added to Master Equation,the equation is solved by the soliton perturbation theory and the theoretical model of the timing jitter is obtained when only considering the quantum noise.Moreover,the theoretical model is applied to analyze the influence on the timing jitter and could provide theoretical guidance for the optimization of the time jitter compared to the numerical simulation result.5.Mode-locked fiber lasers with a repetition rate up to 1 GHz are demonstrated by adopting a new optical design to avoid the risk of the SESAM damage.The coupling efficiency to pump source of the design and the phenomenon of mode-locked are studied experimentally with the fiber laser.Based on the theoretical analysis and the numerical simulation,this paper provides theoretical guidance for the optimization of the time jitter of the mode-locked fiber laser.Moreover,femtosecond fiber lasers with high repetition rate are also constructed experimentally.