Simultaneous measurement of strain and temperature using a Fabry–Perot interferometer consisting of Bragg gratings in polarization-maintaining fiber and current-modulated laser diodes

Abstract

A fast and high-resolution simultaneous measurement of strain and temperature using an optical fiber sensor is presented. Temperature and strain can be measured simultaneously by using two types of reflection spectra of a Fabry–Perot interferometer consisting of fiber Bragg gratings in a polarization-maintaining fiber (PM-FBG-FPI). The fine structure of a reflection spectrum of the PM-FBG-FPI enables the high-resolution detection of wavelength shifts. We present a fast interrogation method with current modulation of a laser diode for PM-FBG-FPI sensors. The resulting fast measurement is demonstrated experimentally.

Simultaneous strain and temperature measurement using a single fiber Bragg grating embedded in a composite laminate

“…The most straightforward approach is to use a reference FBG that is exposed to temperature change only while the main FBG is exposed to both temperature and strain variations [9]. Another method is combining an FBG sensor with a sensor of different type, such as a long period grating, an etched FBG, a Fabry-Perot interferometer, multimode interferometer etc [10][11][12][13][14][15][16]. Temperature compensation was achieved by generating an additional reflectance peak that is separated from the original FBG reflectance peak.…”

Investigation of a Bragg Grating-Based Fabry–Perot Structure Inscribed Using Femtosecond Laser Micromachining in an Adiabatic Fiber Taper

“…An inline FPI can simply be formed by using Bragg gratings instead of reflecting mirrors [21] which also enables the ease of packaging, array manufacturing, etc. Some applications making use of these configurations have been reported, such as cavity sensor for strain and temperature measurement [22]; strain measurement independent of temperature [23] (using KrF 2 excimer laser with phase mask); humidity and temperature measurement [24], for reducing cross-sensitivity between strain and temperature using polarization maintaining fiber [25,26]; etc. Microfiber or small-diameter fiber-based sensors [27], resonators [28], and gratings [29] have been reported recently because these fibers offer unique properties, such as tight confinement, low-transmission loss, higher evanescent fields, etc.…”