Integrated Microfibre Device for Refractive Index and Temperature Sensing

• Main Authors: Lim, Kok Sing, Aryanfar, Iman, Chong, Wu Yi, Cheong, Yew Ken, Harun, Sulaiman Wadi, Ahmad, Harith
• Format: Article
• Published: MDPI 2012
• Subjects: QC Physics; TK Electrical engineering. Electronics Nuclear engineering
• Online Access: http://eprints.um.edu.my/19927/; https://doi.org/10.3390/s120911782

A microfibre device integrating a microfibre knot resonator in a Sagnac loop reflector is proposed for refractive index and temperature sensing. The reflective configuration of this optical structure offers the advantages of simple fabrication and ease of sensing. To achieve a balance between responsiveness and robustness, the entire microfibre structure is embedded in low index Teflon, except for the 0.5-2 mm diameter microfibre knot resonator sensing region. The proposed sensor has exhibited a linear spectral response with temperature and refractive index. A small change in free spectral range is observed when the microfibre device experiences a large refractive index change in the surrounding medium. The change is found to be in agreement with calculated results based on dispersion relationships.