A Whispering-Gallery Mode Microsphere Resonator Based on Optical Fiber With an Open Microcavity

A whispering-gallery mode microsphere resonator based on optical fiber with an open microcavity is demonstrated, which is created by use of femtosecond laser micromachining and fusion splicing techniques. When a microsphere is placed into the open microcavity, whispering-gallery mode can be excited through evanescent field coupling. The device can be constructed in either single-mode fiber or multimode fiber, with the insertion loss of ~13.2 and ~21.0 dB, and the quality factor of 4.81X10
³
and 2 X10
⁵
respectively. Because of its features of compact structure, low cost, easy fabrication, convenient operation and high durability, the device is expected to have many photonics applications.