FBG-based wavelength-shift detection system with enhanced temperature sensitivity

Abstract

Proposed and demonstrated in this letter is a scheme of fiber Bragg grating (FBG) interrogation system based on thermistance and matching-FBG of temperature sensitivity enhancement. According to the relationship between the period of the matching-FBG and the resistance value of the thermistance, the scheme interrogates the wavelength-shift by adjusting the matching-FBG's temperature and detecting the resistance value of the thermistance. In measured experiments, the results show that the precision of the proposed system is 0.048nm in a range of 5.9nm.FBG sensors have attracted a considerable amount of interests in the last ten years for use in optical-fiber sensingVarious wavelength-shift detection schemes based on FBG sensors have been developed, including the optical filtering, and the interferometry, etc. Some of these schemes have obtained high interrogation resolution of wavelength-shift [4] [5] . However, due to the complex structure and the high cost, these schemes have not been generally applied [6][7] . With the development of FBG sensor's applications, it is important to construct FBG-based wavelength-shift detection systems that feature in low cost, small size, low complexity and high utility. In this letter, we report a novel wavelength-shift detection system based on matching-FBG of temperature sensitivity enhancement and thermistance, which utilizes the relationship between the reflective wavelength of the matching-FBG of temperature sensitivity enhancement and the resistance value of the thermistance.To give a general comprehension, an FBG-sensor system, capable of the demodulation function of wavelength-shift detection, is shown in Fig.1, in which the matching-FBG filtering is the most important technique. BBS coupler FBG sensor IMG Matching-FBG O/E Data detection and disposal FC The wavelengthshift detection stystem Fig.1 The schematic diagram of the FBG-sensor structureIn this system, the Polymer-Packaged FBG sensor is connected with the wavelength-shift detection system. The matching-FBG of temperature sensitivity enhancement is implemented via a FC connector to the coupler and then to Passive Components and Fiber-based Devices II, edited by