A highly compact biocompatible microprobe type fiber optic temperature sensor was experimentally demonstrated utilizing an inherently high thermo-optic coefficient of DNA biopolymer. The sensor was based on an all-fiber multimode interferometer (MMI) along a coreless silica fiber (CSF) spliced to an end of a single mode fiber. Au film was deposited the CSF end facet to provide a double path for MMI and it also worked as a probe terminal. The circumferential area of CSF was coated with DNA-cetyltrimethylammonium chloride (CTMA) thin solid film, which served as a temperature sensing head. We experimentally investigated thermo-optical properties of DNA-CTMA thin solid films to find its large negative thermo-optical coefficient -4.15 × 10-4/°C in the temperature range from 20 to 70 °C. DNA-CTMA coated fiber optic probe was immersed in a water bath to simulate the bio compatible environment whose temperature was varied in the range from 30 to 70 °C. The proposed sensor showed a high-temperature sensitivity of -0.22 nm/°C in the spectral shifts, and 0.085 dB/°C in the reflected optical power changes. The proposed probe can be readily applied in various types of in vivo point of care temperature monitoring.
Bibliographical noteFunding Information:
Manuscript received July 28, 2017; revised October 26, 2017; accepted November 25, 2017. Date of publication December 14, 2017; date of current version February 24, 2018. This work was supported in part by ICT R&D Program of MSIP/IITP under Grant 2014-044-014-002, in part by the Research Fund of High Efficiency Laser Laboratory, Agency for Defense Development of Korea (UD160069BD), and in part by Nano Material Technology Development Program through NRF funded by the MSIP under Grant NRF-2012M3A7B4049800. (Corresponding author: Kyunghwan Oh.) The authors are with the Photonic Device Physics Laboratory, Institute of Physics and Applied Physics, Yonsei University, Seoul 120-749, South Korea (e-mail: firstname.lastname@example.org; email@example.com; firstname.lastname@example.org; email@example.com).
All Science Journal Classification (ASJC) codes
- Atomic and Molecular Physics, and Optics