Research On Self Injection Locking Module Of Semiconductor Laser For Optical Frequency Comb

The optical frequency comb is a high coherent light source with equal frequency spacing,which can be used as a high precision optical frequency ruler to accurately measure time and frequency.Microcavity optical frequency combs have the advantages of small size,low power consumption and monolithic integrability.The silicon nitride microring resonator with ultra-low loss and a high Q value is an ideal resonator for realizing microcavity optical frequency comb.DFB semiconductor lasers have the advantages of small size,low cost,and mature manufacture technology.Locking the DFB semiconductor laser through self-injection with a microring resonator can narrow its line width.Using the self-injection locked DFB laser as the pump of the microcavity optical frequency comb,the pump light can automatically track the resonant frequency in the cavity,and complex tuning or feedback control will no longer be required to ensure the generation of the optical frequency comb.First,in this dissertation,the silicon nitride micro-ring resonator is designed comprehensively,which is not only the platform to generate optical frequency comb,but also the external cavity of self-injection locking of the pump laser in the microcavity optical frequency comb.A hybrid integration module of a DFB semiconductor laser and a silicon nitride micro-ring resonator is preliminarily designed.Then,the stability of the self-injection locked DFB semiconductor laser is studied theoretically and experimentally.First,the inner factors affecting the stability of the self-injection locking system are discussed by simulation.Then,the factors affecting the stability of the self-injection locking system caused by external interference are analyzed.Finally,the Damascus process for preparing silicon nitride optical waveguide is explored.The process procedures of hard mask prepare,groove etching in the substrate and deposition of silicon nitride film have been carried out.The processing results under different working conditions are analyzed,and the process conditions are optimized.In summary,the design of the silicon nitride microring resonator for the self-injection locking microcavity optical frequency comb is accomplished,the factors affecting the stability of the self-injection locking system are revealed,and the Damascus process is explored.Work in this dissertation has reference significance for realizing the on-chip integrated optical frequency comb.