Micromachines (Oct 2022)

Adaptive Fiber-Ring Lasers Based on Isopropanol Filled Microfiber Coupler for High-Sensitivity Temperature Sensing

  • Weihao Lin,
  • Jie Hu,
  • Fang Zhao,
  • Siming Sun,
  • Yuhui Liu,
  • Shuaiqi Liu,
  • Feihong Yu,
  • Peng-Un Mak,
  • Sio-Hang Pun,
  • Perry-Ping Shum,
  • Mang-I Vai,
  • Liyang Shao

DOI
https://doi.org/10.3390/mi13101697
Journal volume & issue
Vol. 13, no. 10
p. 1697

Abstract

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We demonstrated a new method for temperature measurement inside a fiber ring laser (FRL) cavity. Different from traditional FRL temperature sensing system which need additional filter working as a sensor, a micro-fiber coupler (MFC) was designed as a beam splitter, filter, and temperature sensor. In addition, isopropanol, a liquid with very high photothermal coefficient, is selectively filled in the MFC in order to improve the sensitivity of the system on temperature. In the dynamic range of 20–40 °C, we obtained a good temperature sensitivity of −1.29 nm/°C, with linear fitting up to 0.998. Benefiting from the advantages of laser sensing, the acquired laser has a 3 – dB bandwidth of less than 0.2 nm and a signal-to-noise ratio (SNR) of up to 40 dB. The proposed sensor has a low cost and high sensitivity, which is expected to be used in biomedical health detection, real-time monitoring of ocean temperature, and other application scenarios.

Keywords