FBG Interrogation Method with High Resolution and Response Speed Based on a Reflective-Matched FBG Scheme

Abstract

In this paper, a high resolution and response speed interrogation method based on a reflective-matched Fiber Bragg Grating (FBG) scheme is investigated in detail. The nonlinear problem of the reflective-matched FBG sensing interrogation scheme is solved by establishing and optimizing the mathematical model. A mechanical adjustment to optimize the interrogation method by tuning the central wavelength of the reference FBG to improve the stability and anti-temperature perturbation performance is investigated. To satisfy the measurement requirements of optical and electric signal processing, a well- designed acquisition circuit board is prepared, and experiments on the performance of the interrogation method are carried out. The experimental results indicate that the optical power resolution of the acquisition circuit border is better than 8 pW, and the stability of the interrogation method with the mechanical adjustment can reach 0.06%. Moreover, the nonlinearity of the interrogation method is 3.3% in the measurable range of 60 pm; the influence of temperature is significantly reduced to 9.5%; the wavelength resolution and response speed can achieve values of 0.3 pm and 500 kHz, respectively.

Gasoline Quality Sensor Based on Tilted Fiber Bragg Gratings

“…Standard and tilted fiber Bragg gratings were used in the setup to be described herein. Bragg gratings (FBGs) consist of periodic refractive index modulations along the core of an optical fiber, which allow coupling between forward and backwards propagating core modes [19]. The coupling occurs at wavelengths, λ FBG , at which the phase matching condition, Equation 1, is satisfied (where n eff core is the effective refractive index of the core mode and Λ is the grating period).…”

Numerical and Experimental Analysis of Matched Filter Interrogation of FBG Sensors with Large Side Lobes

“…They are called wideband edge filters and matched filters [ 14 , 15 ] and have spectra similar to that of the sensor itself. Further improvement of the properties of such systems can be obtained through the use of a parallel matching technique [ 16 , 17 ]. In the second example, properly selected FBG periodic structures are used.…”

“…Depending on the shapes of the spectra of both gratings used in the transmissive and reflective systems, slightly different properties can be obtained ( Figure 1 ). Systems with matched filter interrogation have been considered in the literature in various aspects, e.g., in terms of linearity or speed of operation [ 16 ]. When considering the shapes of sensor transfer characteristics, the most important task of an optical filter system is to achieve proper linearity or to increase the dynamic range of the system [ 18 ].…”

Intensity and Wavelength Division Multiplexing FBG Sensor System Using a Raman Amplifier and Extreme Learning Machine

“…Fiber Bragg grating (FBG) is a favorable fiber optic sensor to measure strain, pressure, vibration, and temperature in different applications, such as in smart structures, wind turbines, aerospace, industry, military, medical centers, and civil engineering. In addition, applications of FBG sensors related to bridge monitoring, damage detection, structural health monitoring, railway transportation applications, and other harsh environment applications [1][2][3]. FBG sensors have the advantages of being immune to electromagnetic interference, light weight, small size, highly accurate, longer stability, and capable in measuring ultra-high-speed events.…”