Temperature-Insensitive Fiber Bragg Grating-Based Bending Sensor Using Radio-Freqeuncy-Modulated Reflective Semiconductor Optical Amplifier

Abstract

A novel method for the temperature-insensitive measurement of the bending of a cantilever plate is proposed. It is based on the radio-frequency (RF) power measurement of the beat signal that has been generated from a dual fiber Bragg grating (FBG)-based sensing head. Another noticeable feature is that a sine-modulated amplified spontaneous emission from a directly modulated reflective semiconductor optical amplifier (RSOA) is employed as a broadband light source.

Performance comparison of Raman/erbium-doped-fiber hybrid-amplification-based long-distance fiber Bragg grating sensor systems

“…All of the sensor systems were based on the demodulation scheme that uses RF power measurements of a beat signal [5]. We used a directly RF signal-modulated RSOA to produce a sinusoidally modulated broadband beam [11]. The RF-modulated broadband beam was propagated over a transmission link composed of a 50 km standard single-mode fiber (SMF) and a 4 m EDF through an optical circulator.…”

“…This means that no additional GVD medium is required in front of the photodetector, unlike previous configurations using the RF power beat signal measurement [5,11]. The three sensor system configurations have the following features: Type I has an EDF section after the distributed Raman amplification section, Type II has an EDF section prior to the distributed Raman amplification section, and Type III has only a distributed Raman amplification section.…”

“…The FBG sensing systems used in this investigation are based on the demodulation scheme that uses RF power measurements of a beat signal. More specifically, a sinemodulated amplified spontaneous emission (ASE) from a directly modulated reflective semiconductor optical amplifier (RSOA) is employed as a broadband light source [11]. The main thrust of this investigation was in finding the most power-efficient and accurate long-distance FBG sensor system among the three configurations.…”

Multi-point strain measurement using Fabry–Perot interferometer consisting of low-reflective fiber Bragg grating

“…[1][2][3] In particular, sensing using an optical fiber type device called an optical fiber Bragg grating (FBG) has features [4][5][6][7] such as being able to localize a sensing part, being simple in configuration, easy in miniaturization. Many means for measuring physical quantities such as temperature, [8][9][10][11][12][13][14] strain, [15][16][17][18][19] acoustic pressure, [20][21][22] and solid vibrations [23][24][25][26][27][28] have been proposed.…”

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

“…The reflection wavelength, which is called the Bragg wavelength, shifts as a result of temperature change or applied strain. The Bragg wavelength shift can be used to measure temperature, [4][5][6][7][8][9][10] strain, [11][12][13][14][15] acoustic pressure, [16][17][18] and solid vibrations. [19][20][21][22][23][24] However, since an FBG sensor has cross-sensitivity between temperature change and applied strain, the sensor cannot be used under a condition where both temperature and strain change independently of each other.…”