We demonstrate an ultrasensitive temperature sensor by sealing a highly-birefringent microfiber into an alcoholinfiltrated copper capillary. With a Sagnac loop configuration, the interferometric spectrum is strongly dependent on the external refractive index (RI) with sensitivity of 36800nm/RIU around RI=1.356. As mainly derived from the ultrahigh RI sensitivity, the temperature response can reach as high as −14.72 nm/°C in the range of 30.9-36.9 °C. The measured response time is ~8s, as determined by the heat-conducting characteristic of the device and the diameter of the copper capillary. Our sensor is featured with low cost, easy fabrication and robustness.

Date Published: 15 October 2013
PDF: 4 pages
Proc. SPIE 8924, Fourth Asia Pacific Optical Sensors Conference, 89240C (15 October 2013); doi: 10.1117/12.2034171

Published in SPIE Proceedings Vol. 8924:
Fourth Asia Pacific Optical Sensors Conference
Minghong Yang; Dongning Wang; Yun-Jiang Rao, Editor(s)