Studies On Whispering Gallery Mode Microcavity Laser Based On Rare Earth Ions Doped Glass Material

Lasers based on the whispering gallery mode microcavity have become an ideal signal source for the construction of a variety of micro-nano photonic devices due to their low threshold,narrow line width,and small size.They can be used in high-sensitivity biochemical detection,photon computing,optical information storage,and other fields.However,some related mechanisms and laser control methods still need to be further studied.As to the applications,the micro-nano photonic devices based on whispering gallery mode are very fragile,and the preparation process is complex.These problems make a lot of research work stay in the laboratory research stage,which is difficult to put into practical application.Therefore,further simplifying the preparation process and improving the standardized preparation level has become one of the current research hotspots.Besides,whispering gallery mode lasers based on various optical materials need to be developed for more special applications.This dissertation focuses on the preparation method,laser control,laser characteristics,and packaging of the whispering gallery mode laser made of rare earth doped glass materials.The main research contents are as follows:1.The evaporation characteristics of rare earth ion doped silica glass were studied and the trace loss of rare earth ions in the evaporation process of doped silica fiber was quantitatively studied.Based on the research results,a method of preparing active microsphere microcavity by evaporating rare earth ion doped silica glass fiber was proposed,and the concentration calculation formula of the microcavity was given.The preparation method has the characteristics of adjustable size,controllable concentration and simple preparation,and can also be used to adjust the size of the passive microsphere microcavity.2.The characteristics of the silica glass whispering gallery mode laser were studied,including the characteristics and comparison of Ho³⁺,Yb³⁺-Ho³⁺and Tm³⁺doped 2.0μm band silica glass microsphere lasers.The effect of doping concentration of Tm³⁺on the laser output wavelength was studied and the mechanism of the related phenomenon was explained based on the reabsorption effect.The tuning mechanism of the whispering gallery mode laser was discussed and a tuning method of the whispering gallery mode laser by changing the polarization state of the pump laser was proposed.In the Yb³⁺-Ho³⁺codoped silica glass microsphere laser,the continuous tuning of the output laser wavelength in the range of 0.6 nm was realized.3.Whispering gallery mode microsphere lasers based on tellurite glass were studied.Through Yb³⁺-Ho³⁺codoped glass microsphere laser,the characteristics of tellurite glass and silica glass in the 2.0μm band microcavity laser were analyzed and compared.A Tm³⁺-Ho³⁺codoped 1.47μm tellurite glass microsphere laser was characterized.By using tellurite glass material to provide a low-phonon energy environment for rare earth ions,the non-radiative transition during the transition from ³H₄ to ³F₄ of Tm³⁺is reduced,and the luminescence of 1.47μm is enhanced.0.2Tm³⁺and 0.2Tm³⁺-0.8Ho³⁺codoped tellurate glass samples were prepared respectively,and the fluorescence lifetime decay curves of ³F₄ level of Tm³⁺in the two samples were tested and their fluorescence lifetimes were calculated.The results show that the fluorescence lifetime of the ³F₄ level is effectively reduced by codoping Ho³⁺with Tm³⁺,so it satisfies coditions for population inversions to generate laser.4.The properties of antenna waveguide as whispering gallery mode microcavity couplers were investigated,and the different forms of resonant spectrum in antenna-microsphere system were observed.A method for packaging whispering gallery mode devices based on antenna waveguide couplers was proposed.The passive package devices prepared based on this method barely lead to the degradation of the quality factor of the whispering gallery mode system.Using the same packaging scheme,an Er³⁺-doped packaged whispering gallery mode laser was prepared,and its performance was studied.The device has the advantages of fully enclosed,small,and easy to combine with other fiber components.It initially can work outside laboratory conditions.