Research On Thermal Stability And Sideband Characteristics Of Silicon Nitride Microcavity Optical Frequency Comb

The integrated photonics chip has attracted more and more attention because of its small size,extensibility,high stability and low power consumption.It has been widely used in the field of classical optical communication.In recent years,optical quantum chips based on the principle of quantum optics have developed rapidly,which is expected to promote quantum optics to achieve significant progress in quantum communication,quantum computing and other fields.On the optical quantum chip,photons need to be generated,processed and detected to achieve specific functions such as quantum communication,quantum simulation and quantum computing.The on-chip quantum light source is used to generate single photon,entangled photon pair and compressed light,and is an important component in optical quantum chip system.The optical frequency comb based on microcavity can generate single photon and associated photon pairs on chip,which is an effective quantum light source on chip.This paper focuses on the study of microcavity optical frequency comb based on silicon nitride,and carries out theoretical and experimental research on thermal self-stability and edge mode intensity difference compression,which provides a necessary basis for quantum optical experiments based on quantum microcomb light source.Specifically,it includes the following aspects:1.The modal evolution of optical comb based on high Q value silicon nitride microcavity was studied.The performance of the microcavity optical comb was characterized by transmission spectrum scanning test and spectral analysis.Combined with the test data,the modal evolution characteristics of the microcavity under different pumping conditions were analyzed,and the optical power level and detuning in the cavity were determined as the main factors of the modal evolution.Based on this,the emergence conditions of the "three-mode" state,the "Turing ring" state and the chaotic state were obtained,and the general rules of the microcavity transmission spectrum were summarized.2.The thermal self-stability of microcavity was studied.The principle and rule of microcavity thermal homeostasis are analyzed theoretically,the formation process of microcavity thermal homeostasis is verified experimentally,and the anti-interference ability of microcavity optical frequency comb thermal homeostasis is tested.The results show that the microcavity can compensate the noise by resonance drift and can compensate the influence caused by power disturbance.The microcavity can maintain thermal stability for more than 5 minutes without interference,which indicates that the microcavity thermal autostability has practical value.3.The sideband correlation characteristics of microcavity optical frequency comb are studied,and the experimental scheme of first-order sideband strength difference compression test for microcavity is designed.According to the experimental results,the problems of existing test schemes are analyzed,and the corresponding solutions are put forward.