[OPTICAL REVIEW Vol. 18, No. 1 (2011) 144-148]
© 2011 The Japan Society of Applied Physics

Fabrication and Comparison of Thermochromic Material-Based Fiber-Optic Sensors for Monitoring the Temperature of Water

Wook Jae YOO, Jeong Ki SEO, Kyoung Won JANG, Ji Yeon HEO, Jin Soo MOON, Jang-Yeon PARK, Byung Gi PARK1, and Bongsoo LEE*

School of Biomedical Engineering, College of Biomedical and Health Science, Research Institute of Biomedical Engineering, Konkuk University, Chungju 380-701, Korea
1Department of Energy and Environment Engineering, College of Engineering, Soonchunhyang University, Asan 336-745, Korea

(Received May 31, 2010; Accepted October 26, 2010)

In this study, we explored the feasibility of developing two types of fiber-optic temperature sensors that can measure the temperature of water. One uses a thermochromic material such as Lophine, whose optical absorbance changes according to the thermal variation. The other uses a thermochromic pigment that gradually loses its own color through heat absorption. We measured the change in the intensity of the reflected light, which was due to the variation of the optical property of Lophine and pigments, with thermal variation. The relationship between the temperature of water and the output signal of the fiber-optic sensors was also determined. The fiber-optic temperature sensor using Lophine provided a relatively broad range of temperature measurement with low sensitivity, whereas the fiber-optic temperature sensor using a thermochromic pigment offered a high sensitivity in a narrow range of temperature measurement.

Key words: fiber-optic sensor, plastic optical fiber, temperature sensor, thermochromic material, thermochromic pigment

*E-mail address: bslee@kku.ac.kr