title: Fiber pigtailed thin wall capillary coupler for excitation of microsphere WGM resonator.
abstract: In this paper, we demonstrate a fiber pigtailed thin wall capillary coupler for excitation of Whispering Gallery Modes (WGMs) of microsphere resonators. The coupler is made by fusion-splicing an optical fiber with a capillary tube and consequently etching the capillary wall to a thickness of a few microns. Light is coupled through the peripheral contact between inserted microsphere and the etched capillary wall. The coupling efficiency as a function of the wall thickness was studied experimentally. WGM resonance with a Q-factor of 1.14 × 10(4) was observed using a borosilicate glass microsphere with a diameter of 71 μm. The coupler operates in the reflection mode and provides a robust mechanical support to the microsphere resonator. It is expected that the new coupler may find broad applications in sensors, optical filters and lasers.
authors.affiliation: Department of Electrical and Computer Engineering, Missouri University of Science and Technology, Rolla, MO 65409, USA.
authors.forename: Hanzheng
authors.initials: H
authors.lastname: Wang
authors.forename: Xinwei
authors.initials: X
authors.lastname: Lan
authors.forename: Jie
authors.initials: J
authors.lastname: Huang
authors.forename: Lei
authors.initials: L
authors.lastname: Yuan
authors.forename: Cheol-Woon
authors.initials: CW
authors.lastname: Kim
authors.forename: Hai
authors.initials: H
authors.lastname: Xiao