FiberBragggratingtemperaturesensorAreview.docVIP

Fiber Bragg grating temperature sensor－A review Abstract:In recent years, considerable progress has been made in optical fiber sensors using a fiber Bragg grating (FBG). This is because such FBG sensors have many advantages for practical applications: ease of multiplexed operation, compactness, quasi-point sensing capability and simple structure. Fiber Bragg gratings (FBG)have generated much interest for use as sensors for strain, temperature, and other physical quantities because of their important properties such as immunity to electromagnetic noise, high sensitivity, compactness, and simplicity of fabrication. OCIS codes: (060.2370) Fiber optics sensors; (230.1480) Bragg reflectors. 1. Introduction Fiber Bragg grating (FBG) has been intensively studied and developed as an optical sensor for various sensing applications, such as health monitoring of civil structure, non-destructive testing of composite materials, smart structure, and traditional stain, pressure, and temperature sensing [1]. To realize practical sensor systems with multiplexing capability, various kinds of FBG array interrogation techniques have been suggested [2]. Recently, the demand for warning the abnormal temperature increase at restricted spaces has been rapidly increasing. In particular, due to different tolerable thresholds required at different locations, it is necessary to construct the low cost and easy interrogation configuration. In this letter, a novel multi-point temperature warning sensor using a multi-channel matched FBG-based multi-wavelength pulsed laser is proposed and demonstrated. The sensor has several advantages, including flexible setting of the tolerable temperature, simple structure, high signal-to-noise ratio, low system cost and quick response. 2. Background （1） Intracore fiber Bragg gratings for strain measurement in embedded composite structures The Bragg wavelength is given by , (1) where is the effective refractive index of the fiber (modal index) and L