Fiber In-Line Michelson Interferometer Tip Sensor Fabricated by Femtosecond Laser

Abstract

A fiber in-line Michelson interferometer tip sensor based on open micro-cavity, which is fabricated by femtosecond laser micromachining and the thin film coating technique, is proposed and demonstrated. When used in refractive index sensing, such an interferometer operates in a reflection mode of detection, and exhibits a compact sensor head, good mechanical reliability, wide operation range, and high sensitivity of 975 nm/refractive index unit at a refractive index value of 1.484.