In-Line Fiber Optic Interferometric Sensors in Single-Mode Fibers

Abstract

In-line fiber optic interferometers have attracted intensive attention for their potential sensing applications in refractive index, temperature, pressure and strain measurement, etc. Typical in-line fiber-optic interferometers are of two types: Fabry-Perot interferometers and core-cladding-mode interferometers. It's known that the in-line fiber optic interferometers based on single-mode fibers can exhibit compact structures, easy fabrication and low cost. In this paper, we review two kinds of typical in-line fiber optic interferometers formed in single-mode fibers fabricated with different post-processing techniques. Also, some recently reported specific technologies for fabricating such fiber optic interferometers are presented.

Refractive index desensitized optical fiber temperature sensor

“…A number of sensing technologies including fiber Bragg gratings [4,5], long period gratings [6], and various configurations of interferometers [7,8], have been developed and studied for temperature measurement with reduced cost, increased sensitivity, or enhanced temperature range [6,8]. Recently, interference between guided modes of optics fibers for temperature fiber sensors have been reported [7,8,9,10].…”

“…Recently, interference between guided modes of optics fibers for temperature fiber sensors have been reported [7,8,9,10].…”

Cost effective refractive index sensor based on optical fiber micro cavities produced by the catastrophic fuse effect

“…Recently, the use of Fabry-Perot Interferometer (FPI) micro cavities became attractive due to their reduced dimension, linear response and high sensitivity [9,10]. These devices are composed by two separated reflecting surfaces where the optical signals can be partially reflected.…”

Photonic crystal fiber Fabry-Perot interferometers with high-reflectance internal mirrors

“…All fiber in-line Fabry-Perot interferometers (FPIs) have advantages of the compact size, high resolution, excellent stability, and insensitivity to temperatures [1,2]. So researchers have been developing different methods to fabricate the air cavity based on different techniques, for example wet chemical etching [3,4], laser micromachining [5,6], and splicing different types of optical fibers with the commercialized fusion splicer [7][8][9][10][11][12].…”