Humidity Sensor Based on Fabry–Perot Interferometer and Intracavity Sensing of Fiber Laser

• Published in: Journal of lightwave technology Vol. 35; no. 21; pp. 4789 - 4795
• Main Authors: Shi, Jia, Xu, Degang, Xu, Wei, Wang, Yuye, Yan, Chao, Zhang, Chao, Yan, Dexian, He, Yixin, Tang, Longhuang, Zhang, Weihong, Liu, Tiegen, Yao, Jianquan
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.11.2017; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Detection; Fabry-Perot interferometers; Fabry–Perot interferometer; Fiber laser sensor; Fiber optics; Humidity; humidity sensors; Lasers; Noise levels; Optical fibers; Remote sensors; Sensitivity; Sensors; Time response
• ISSN: 0733-8724; 1558-2213
• DOI: 10.1109/JLT.2017.2750172

A humidity sensor based on Fabry-Perot interferometer (FPI) and intracavity sensing of a fiber ring laser is proposed and experimentally demonstrated. A compact humidity-sensitive fiber-optic FPI is developed and inserted in a fiber ring laser. Because the output power of the fiber laser is modulated by the reflection loss of the FPI at different ambient humidity, intracavity humidity sensing is induced. The experiment shows that the relative output power of the fiber laser has a good linear response to ambient humidity from 25%RH to 95%RH and the humidity sensitivity of 0.202 dB/%RH is obtained with a narrow 3-dB bandwidth and high signal-to-noise ratio. Furthermore, the excellent performance of the sensor for remote humidity detection is demonstrated. The sensor also shows a low temperature cross-sensitivity, fast time response, and good stability. The proposed sensor has a great potential in high-capacity sensor network and remote detections.