Design of fiber Bragg grating-based Fabry–Perot sensor for simultaneous measurement of humidity and temperature

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

“…Figure 2 shows the normalized reflection spectrum of the FP structure in a standard optical fiber. Yulianti et al [24] also provided a set of modeling equations for designing an FP structure based on complex reflection and transmission coefficients of the uniform grating, i.e., Equations (2) and (3). The amplitude reflection coefficient of the FP, r f p2 (λ) is given by Equation 7, and its power reflection coefficient is defined by, R = |r f p2 (λ)| 2 .…”

“…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.…”

Design of an optical temperature transmitter for inflammable industry

“…Based on U-shaped bent singlemode fibre, a FBG temperature calibration system employed, light intensity modulation temperature sensor has been presented by Peng et al [20]. Fabry-Perot cavity formed by two identical uniform fibre Bragg gratings, which serves as sensor has been designed by Yulianti et al [21] that responds to both RH and temperature. The sensor improved the sensitivity performance for RH and temperature.…”

A Dual-Polymer Fiber Fizeau Interferometer for Simultaneous Measurement of Relative Humidity and Temperature

“…In the above mentioned processes, the simultaneous measurement of RH and T provides a number of engineering advantages and is often a necessity for a variety of system applications. In recent years, several fiber optical sensors for simultaneous RH and T sensing have been proposed and investigated, but most of them are incorporated with well-known fiber devices such as fiber Bragg gratings (FBGs) [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 ], long-period fiber gratings (LPFGs) [ 8 , 9 , 10 ], and Fabry-Perot interferometers (FPIs) [ 1 , 11 , 12 , 13 ]. In [ 1 ], Arregui et al proposed a sensor head composed of an FBG and a low-finesse FPI for simultaneous RH and T sensing.…”

“…Massaroni C. et al proposed a configuration based on an array of FBGs for achieving the simultaneous measurement of both T and RH of gas in a chamber [ 5 ]. Another sensor consisting of a Fabry–Perot cavity formed by two identical FBGs was proposed in [ 6 ], where the polyimide material was coated on the FBG and also on the cavity with a different thickness. RH and T sensitivities of 1.92 pm/% RH and 8.87 pm/°C, respectively, with coating thicknesses of 10 μm on the FBG and 15 μm on the cavity, were shown.…”