Research On Generation Of 100GHz Kerr Soliton Frequency Combs In Polarizationmaintaining Scheme

Optical frequency comb is a coherent light source composed of a series of optical frequency spectral lines with strict equal spacing and locked phase.It is a variable speed gear connecting light and microwave frequencies,and can realize the synchronization and mutual conversion between the number of periods of light wave oscillation and the number of periods of microwave oscillation.It has a wide application prospect in the fields of optical atomic clock,optical frequency measurement,molecular absorption spectroscopy and microwave photonics.In this paper,the generation technology of 100 GHz Kerr optical frequency comb under the condition of full polarization maintaining is explored and studied by means of simulation and experimental research.Specific work includes:1.Firstly,the cavity enhancement of light and matter in several optical microcavities is introduced,and the generation mechanism of Kerr optical frequency comb is combed.A numerical model based on Lugiato-Lefever equation is established,and the generation process of Kerr optical frequency comb at 100 GHz is simulated,which provides theoretical support for the generation of Kerr optical frequency comb in the subsequent fully polarization-maintaining system.2.Secondly,according to the demand of signal processing for Kerr optical frequency comb,starting with the design of silicon nitride chip parameters,a silicon nitride waveguide chip capable of generating 100 GHz Kerr optical frequency comb is designed by using optical software simulation.After that,it was manufactured by the foundry,and a microcavity parameter characterization test platform was built,and the free spectral range,Q value and dispersion of silicon nitride microcavity structure in the chip were measured.Ensure that the silicon nitride waveguide chip is in accordance with the designed parameters,and provide support for subsequent experiments.3.Finally,the alignment coupling platform of silicon nitride waveguide chip and optical fiber is built,and the full polarization-preserving package of silicon nitride waveguide chip is realized.Combined with the simulation results,the soliton Kerr optical frequency comb which can work stably for 4 days is produced by means of auxiliary laser heating compensation.In addition,the polarization stability of the output optical frequency comb under polarization-maintaining and non-polarizationmaintaining systems is further compared and characterized,and it is proved that the Kerr optical frequency comb produced under the fully polarization-maintaining structure has superior polarization stability.