Low-cost all-fiber Bragg grating sensing system for temperature and strain measurements

Abstract

A low-cost all-fiber Bragg grating sensing system for temperature and strain measurements is presented. Broadband interrogation and grating-based optical filtering are used to detect a strain- or temperature-induced Bragg wavelength shift with a resolution of 1 us and 0.1 degrees C. The passive nature of the grating demodulation enables dynamic measurements, limited only by the electronic circuitry involved in the system read out. The same system is also used for dynamic strain detection. A fiber grating is bonded to a piezoceramic actuator in different configurations. A laser-triangulation-based system is used as a reference measurements up to 10 kHz, while dynamic strain measurements by a Fiber Bragg grating (FBG) are carried out up to 50 kHz, demonstrating a dynamic resolution of approximate to 40 n epsilon/(Hz)(1/2)

Fiber optic sensor arrays: a new method to improve multiplexing capability with a low complexity approach

“…It is theoretically achievable to multiplex up to 50 FBGs. In respect to the single point sensor set-up [12,19], the complexity increasing of such approach involves only the intensity modulation of the laser source and the A/D conversion with an adequate sampling rate. Experimental measurements are in progress in order to validate the results discussed in this paper.…”

“…In our set-up [12], we use a broadband light source (e.g. a super luminescent diode (SLED)), an in-fiber wavelength optical filter (with linear wavelength-intensity function: linear filter), two Y coupling and a narrow band Bragg gratings as sensing element.…”

“…So far, the wavelength-encoder nature has posed severe limitations to their use due to requirement of complex optical and electronic instrumentation [8][9][10][11]. On this line of argument, we have developed and successfully tested a low cost, all fiber intensity based demodulation techniques for the interrogation of FBGs sensors [12], which is briefly described in the next section.…”

Compensation of hysteresis in magnetic field sensors employing Fiber Bragg Grating and magneto-elastic materials

“…Among various methods, interferometric techniques allow very sensitive and accurate measurements but complex and expensive configurations are required. Passive optical filtering techniques represent a good trade-off in terms of resolution, flexibility and costs [32]. The interrogation system used for the proposed magnetic sensor is passive and relies on a low cost technique based on optical filtering combined with broadband interrogation [26].…”

High resolution temperature insensitive interrogation technique for FBG sensors

“…ibre Bragg grating (FBG) based optical sensing technology has been extensively investigated and developed since the first FBG was demonstrated by Hill et al [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. In many applications, the FBG sensor exists in a variable temperature environment.…”