Research On The Key Technology Of Prism Coupling For High Quality Whispering Gallery Mode Optical Microcavity

With the characteristics of high quality factor and small mode volume,whispering gallery mode(WGM)optical micro-cavity has been broadly applied in the fields of high-sensitivity detection,low-threshold laser,optical nonlinearity and optoelectronic integration.The prism coupling technique of WGM optical micro-cavities has the advantages of flexible tuning,high stability as well as easy to package and integrate,which is of great significance to the engineering applications of WGM optical micro-cavities.This thesis focuses on the difficulties of high-efficiency prism coupling technique for high-quality WGM optical micro-cavity and carries out the following two aspects of work:Optimization of prism-based coupling efficiency for WGM optical micro-cavity was studied and analyzed.By constructing the influence model of microcavity curvature,intracavity attenuation,coupling incident angle and coupling distance on the coupling efficiency of prism coupling,the optimization mechanism of prism coupling efficiency was emphatically studied.Firstly,reducing the attenuation of WGM optical micro-cavity can help to improve the optical energy storage capacity of micro-cavities.Secondly,the optimal optical microcavity curvature can be designed according to the critical coupling angle of incidence,which is the optimal coupling incidence angle of coupling system.Finally,the critical coupling distance should be satisfied between the optical microcavity and the prism to achieve the critical prism coupling state.A high-efficient prism coupling system for WGM optical micro-cavity was designed and complemented.By optimizing and adjusting the key influencing parameters of the prism coupling system,high-efficiency prism coupling of high-quality calcium fluoride and lithium niobate optical micro-cavity were realized based on the experimental platform for prism coupling system.The prism-based coupling efficiency and the loaded quality factor of the lithium niobate optical micro-cavity respectively reached 50%and 1.0×107.For calcium fluoride optical micro-cavity,the prism-based coupling efficiency and loaded quality factor were respectively 80%and 1.7×106.