Application Research On The Fano Resonance Base On Whispering Gallery Mode Microresonator

Whispering gallery mode microresonators are usually dielectric microresonators with sizes ranging from tens to hundreds of microns,such as microspheres,microdisks,and microrings.They can confine light inside the microresonators through continuous total internal reflection.Because of the unique physical characteristics of high quality factor and small mode volume,whispering gallery mode microresonators are widely used in the fields of sensing,low-threshold laser,optical filtering and nonlinear optics.In recent years,due to the unique shape of the Fano resonance in photonics,the spectral line shape can be changed by adjusting the Fano parameter,so it has attracted the attention of researchers.Combining Fano resonance with whispering gallery mode microresonators to study the phenomena and related applications is currently popular research direction.This paper studies the application of Fano resonance based on the whispering gallery mode microresonators and the Fano resonance in millimeter-scale microresonators.The specific research work described in this paper is as follows:(1)The application of high order Fano resonance in a thin-walled liquid core microring is explored.First,the penetration depth of different high order modes in the microring and the relationship between sensitivity and quality factor are analyzed theoretically by numerical simulation.Secondly,the wall thickness of capillary is reduced with hydrofluoric acid solution,and ethanol solution is injected into core.The fiber taper is used to couple the capillary microresonator to excite the Fano mode,and the temperature of the liquid core is controlled,we achieve tunability of Fano resonance wavelength.This wavelength tunability is applied to a ring fiber laser to achieve a continuously linear tunable laser output.(2)The application of the oscillating Fano mode in a conical microresonator is studied.A theoretical model of fiber taper coupling conical microresonator is first established in this paper.The complex ratio of the resonance field to the background field is introduced through the formula.The complex ratio is named after the Fano parameter.Theoretical analysis shows that by changing the coupling size of the fiber ctaper,the Fano parameter can be changed,and then the Fano resonance spectrum can be changed.Then,in the experiment,fiber taper is used to couple the conical microresonator to obtain transmission spectra at different fiber taper coupling diameters.The simulation results show that the experimental results are in good agreement with the theoretical curves.Further,by adjusting the coupling diameter of the conical microresonator,the resonance wavelength can be tuned.Applying it to a fiber laser also achieves a linearly tunable laser output.(3)The fabrication of high quality factor microresonators with millimeter-scale is realized.By using a 2CO laser beam to shape the fused silica preform,millimeter-scale microresonators with quality factor of average above 75?10 are obtained.Using the fiber taper to couple such microresonators can produce Fano resonance with quality factor in the sixth power.