In our proposed technique the wavelength shift of FBG can be determined by change of lasing wavelength of distributed feedback laser (DFB-laser) due to the change of laser substrate temperature. The maximal opto-electrical intensity of photodetector would be obtained when the laser wavelength and FBG reflection wavelength are coincided. The FBG sensor prototype has shown excellent response for laser temperature change in the range of 100C-50 0C with the ratio ∆λ/∆T of the DFB laser is of −1 . Key features of the proposed technique are fabrication of low-cost FBG sensors for civil engineering. | Communications in Physics, Vol. 23, No. 1 (2013), pp. 67-73 DETERMINATION OF WAVELENGTH SHIFT OF FIBER BRAGG GRATING SENSORS BY TUNABLE SINGLE-MODE DIODE LASER NGUYEN THE ANH, PHAM THANH SON, NGUYEN THUY VAN, HOANG THI HONG CAM, NGO QUANG MINH, BUI HUY, AND PHAM VAN HOI Institute of Materials Science, VAST Abstract. We propose a novel principle of determination of fiber Bragg grating (FBG) wavelength shift which is impacted by a variation of physical parameters such as temperature, pressure and/or strain. In common case the wavelength shift of FBG was monitored by wavelength measurement using a high-cost spectrometer and a broad band light source. In our proposed technique the wavelength shift of FBG can be determined by change of lasing wavelength of distributed feedback laser (DFB-laser) due to the change of laser substrate temperature. The maximal opto-electrical intensity of photodetector would be obtained when the laser wavelength and FBG reflection wavelength are coincided. The FBG sensor prototype has shown excellent response for laser temperature change in the range of 100 C-500 C with the ratio ∆λ/∆T of the DFB laser is of −1 . Key features of the proposed technique are fabrication of low-cost FBG sensors for civil engineering. I. INTRODUCTION Optical sensors based on fiber Bragg gratings (FBG) have attracted considerable attention since the early stage of their discovery. FBG sensors have become widely known and researched among the devices in the photonics community and their utilization and commercial growth rised intensively. Given the capability of FBGs to detect the multitude of parameters such as strain, temperature, pressure, chemical and biological agents and many others coupled with their flexibility of design to be used as single point or multipoint sensing arrays and their relative low cost, make them ideal devices to be adopted for a multitude of different sensing applications and implemented in different fields and industries [1].
