Optical fiber sensor system for remote and multi-point refractive index measurement

• Published in: Sensors and actuators. A. Physical. 2016-10, Vol.250, p.29-34
• Main Author: Yüksel, Kivilcim
• Format: Article
• Language: English
• Subjects: Environmental monitoring; Fiber optics; Fiber optics sensors; Fresnel reflection; OTDR; Refractive index sensing; Refractivity; Remote sensors; Sensors; Spatial resolution; Tips
• ISSN: 0924-4247; 1873-3069
• DOI: 10.1016/j.sna.2016.09.003

•Fresnel-reflection-based refractive index (RI) sensor reported.•Multi-wavelength OTDR interrogation scheme introduced.•Experiments show good agreement with theory and precision of 1.7×10−4 obtained.•Advantages: simple installation requirements, fast response and reliability in harsh environment.•Envisaged application is the environmental monitoring systems. A Fresnel-reflection-based RI sensor using SMF fiber tips as sensing points interrogated by multi-wavelength OTDR from a distant location (up to several tens of kilometers) has been reported. The advantage of the system compared to previous work is that the distance between sensor points is not limited by the spatial resolution of OTDR. Experimental work demonstrated that the proposed sensor is capable of measuring refractive index of liquid chemicals with a precision of 1.7×10−4. This sensor prototype have strong conveniences (simple installation requirements, fast response and reliability in harsh environment) compared to previous Fresnel-based RI sensors which makes it a very good option for environmental monitoring systems.