A Reflective Whispering Gallery Mode Microsphere Resonator Integrated With a Thick-Wall Capillary Tube

A reflective whispering gallery mode microsphere resonator is presented. The device consists of a single-mode fiber, a thick-wall capillary tube, and a microsphere. The capillary tube and single-mode fiber are firstly conically fused together using a fusion splicer, followed by tapering the capillary tube, then cut at the end of tapered region of capillary tube, and finally, the microsphere is inserted into the tapered region of capillary tube by use of a fiber taper and a small amount of glue. The device is alignment free, has compact size, good robustness, and stable operation.