Excitation of Whispering Gallery Modes of a Microresonator Integrated in an Optical Fiber Axicon

We report novel designs to excite Whispering Gallery Mode (WGM) of spherical microresonator in an integrated single mode optical fiber tip probe, namely, Deep Seated Negative Axicon (DSNA). The empty DSNA and partially filled polymer DSNA are explored to host the Barium Titanate/Silica microresonator as WGM resonators. An SLD source with a central wavelength of 840 nm and bandwidth of 50 nm is used to excite the microresonator. Reflected spectra are recorded in a spectrometer through an optical circulator for different resonators at various locations. Experimentally the quality factor Q as high as ~ 7\,\,\times10 3 is achieved from the design. It is observed that spectral characteristics and Q value are affected by the resonator's position, size and the material. The Finite Element Method (FEM) simulation results have also been included in support of the design.