Compact refractometer based on extrinsic-phase-shift fiber Bragg grating

✍ Scribed by Wenjun Zhou; Xinyong Dong; Li-Yang Shao; Chi Chiu Chan; Chun-Liu Zhao; Ping Shum

• Book ID: 104092866
• Publisher: Elsevier Science
• Year: 2011
• Tongue: English
• Weight: 711 KB
• Volume: 168
• Category: Article
• ISSN: 0924-4247
• DOI: 10.1016/j.sna.2011.03.054

✦ Synopsis

A novel method to measure refractive index of liquids by using an extrinsic-phase-shift fiber Bragg grating (EPS-FBG) is proposed and experimentally demonstrated. The EPS-FBG is obtained by separating two identical FBG reflectors with a micrometer air gap as a phase-shift. This gap forms a phase-shift peak in the transmission spectrum which is dependent upon the refractive index (RI) of the liquid filled in the gap. A large RI measurement range from 1.33 to 1.47 u.r.i. (unit of refractive index) was obtained in the experiment. Experimental results agreed well with the numerical analysis, showing a linear response with the RI sensitivity of ∼1.69 nm/u.r.i. (RI resolution of ∼5.92 × 10 -3 u.r.i.). Moreover, the micrometer interaction length in the proposed design makes it potential for microfluidic application.