title: Design and characteristics of refractive index sensor based on thinned and microstructure fiber Bragg grating.
abstract: A refractive index sensor based on the thinned and microstructure fiber Bragg grating (ThMs-FBG) was proposed and realized as a chemical sensing. The numerical simulation for the reflectance spectrum of the ThMs-FBG was calculated and the phase shift down-peak could be observed from the reflectance spectrum. Many factors influencing the reflectance spectrum were considered in detail for simulation, including the etched depth, length, and position. The sandwich-solution etching method was utilized to realize the microstructure of the ThMs-FBG, and the photographs of the microstructure were obtained. Experimental results demonstrated that the reflectance spectrum, phase shift down-peak wavelength, and reflected optical intensity of the ThMs-FBG all depended on the surrounding refractive index. However, only the down-peak wavelength of the ThMs-FBG changed with the surrounding temperature. Under the condition that the length and cladding diameter of the ThMs-FBG microstructure were 800 and 14 mum, respectively, and the position of the microstructure of the ThMs-FBG is in the middle of grating region, the refractive index sensitivity of the ThMs-FBG was 0.79 nm/refractive index unit with the wide range of 1.33-1.457 and a high resolution of 1.2 x 10(-3). The temperature sensitivity was 0.0103 nm/ degrees C, which was approximately equal to that of common FBG.
authors.affiliation: Institute for Thermal Power Engineering, State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, China.
authors.forename: Xue-Feng
authors.initials: XF
authors.lastname: Huang
authors.forename: Zhe-Min
authors.initials: ZM
authors.lastname: Chen
authors.forename: Li-Yang
authors.initials: LY
authors.lastname: Shao
authors.forename: Ke-Fa
authors.initials: KF
authors.lastname: Cen
authors.forename: De-Ren
authors.initials: DR
authors.lastname: Sheng
authors.forename: Jun
authors.initials: J
authors.lastname: Chen
authors.forename: Hao
authors.initials: H
authors.lastname: Zhou
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation*; D003198:Computer Simulation; D017076:Computer-Aided Design; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005336:Fiber Optic Technology / Q000295:instrumentation*; D017022:Flow Injection Analysis / Q000295:instrumentation* / Q000379:methods; D008904:Miniaturization; D008962:Models, Theoretical; D012031:Refractometry / Q000295:instrumentation* / Q000379:methods