Soliton Optical Frequency Comb Research Based On High-index Doped Silica Glass Microresonator

Benefiting from low power consumption,high coherence,broad bandwidth and easy-to-integrate ability,high Q microresonator based Kerr soliton optical frequency comb(soliton microcomb)has shown unprecedented advantage in the fields of ultrafast precision ranging,dual-comb spectroscopy,optical frequency synthesis,etc.In recent years,high-index doped silica materials platform has been attractive for its CMOS process compatibility,low loss,mature coupling and packaging techniques.In this dissertation,based on high-index doped silica glass microresonator,the generation process and the dynamics of soliton microcomb is investigated both in theory and experiment.Theoretically,harmonic and sub-harmonic phase-modulation pump scheme are proposed for investigating the generation dynamics of soliton microcomb with higher-order repetition rate.Based on mode coupling and thermal tuning resonance methods,modelocked soliton crystal microcomb with various spectral features are obtained.Based on orthogonal-polarized auxiliary laser heating scheme,single soliton generation dynamics is studied.Finally,three proof-of-concept experiments based on single soliton source are demonstrated.The main contents and conclusions obtained are summarized as follows:1.Harmonic phase modulation pump scheme is proposed,1-4 equidistant soliton states(repetition rate: ?10 GHz-?40 GHz)are realized deterministically.The Raman scattering effect is also investigated?To realize soliton microcomb with even higher repetition rate,sub-harmonic phase modulation scheme is applied,by designing and optimizing the modulation frequency and pump efficiency parameters,5-20 equidistant soliton is realized in a single microcavity,the corresponding repetition rate ranges from?50 GHz-?200 GHz.2.Based on mode coupling effect and thermal tuning resonance method,soliton crystal microcomb with more than 200 nm bandwidth and various spectral features are obtained.Furthermore,taking the wavelength-dependent loss parameters into numerical model,the Raman shock time for high-index doped silica material is calculated as2.5 fs-2.7 fs by precisely comparing the simulated and experimental spectrum.3.By inducing a counter-propagating auxiliary laser that is co-or orthogonal polarized with the pump laser,the intracavity thermal instability is balanced timely,highindex doped silica glass microresonator based single solitons are first realized,the repetition rate is ?48.97 GHz(spectral range ?160 nm)and ?26.09 GHz(spectral range?80 nm),respectively.By tuning the temperature of the TEC,the center wavelength of dispersive wave could be tuned.Based on single soliton microcombs,three proof-ofconcept applications are demonstrated: 1,based on dispersive interferometry method,the absolute distance of ?1179 m is measured with Allen deviation less than 27 nm;2,based on two single-soliton with ?600 k Hz repetition rate difference,the absorption spectrum of HCN at 1530 nm-1560 nm is measured,7 comb lines with more than 3 d B absorption intensity is observed;3,soliton microcomb temporal characterization based on heterodyne beat sampling method using another single soliton microcomb,single-,two-,three-and five-soliton state is characterized.