[1] [1] MA Zhi-zhen. Research and introduction of optical fiber humidity sensor[J]. Application of Power Technology, 2012(10): 31-31.

[2] [2] PENG J, WANG W, Qu Y, et al. Thin films based one-dimensional photonic crystal for humidity detection[J]. Sensors & Actuators A Physical, 2017, 263.

[3] [3] THOMAS P J, HELLEVANG J O. A fully distributed fibre optic sensor for relative humidity measurements[J]. Sensors & Actuators B Chemical, 2017, 247.

[4] [4] LIU Ya-ping. Research on optical fiber CRDS technology and LPFG humidity sensor[D]. Nankai University, 2009.

[5] [5] ZAHNG Xiang-dong, LI Yu-lin, PENG Wen-da, et al. Design and implementation of fiber Bragg grating temperature and humidity sensor[J].Acta Photonica Sinica,2003, 32(10): 1166-1169.

[6] [6] LIAO Zhao-long, LIU Hong-liang, YANG Ming-hong, et al. Research on humidity sensor based on optical fiber F-P cavity[J]. Science Forum, 2010(4): 91-92.

[7] [7] CHEN H, KARION A, RELLA C W, et al. Accurate measurements of carbon monoxide in humid air using the cavity ring-down spectroscopy (CRDS) technique[J]. Atmospheric Measurement Techniques, 2013, 6(4): 1031-1040.

[8] [8] CHEN B, WANG J, SUN Y R, et al. Broad-range detection of water vapor using cavity ring-down spectrometer[J]. Chinese Journal of Chemical Physics, 2015, 28(4): 440-444.

[9] [9] ZHAN X, WANG Y L, LI L, et al. Determining critical relative humidity by measuring air humidity in equilibrium directly[J]. European Journal of Pharmaceutical Sciences, 2010, 41(2): 383.

[10] [10] XIONG Y, MENG Q S, GAO J, et al. Effects of relative humidity on animal health and welfare[J]. Journal of Integrative Agriculture, 2017, 16(8): 1653-1658.

[11] [11] NI N, CHAN C C, WONG W C, et al. Cavity ring-down long period grating pressure sensor[J]. Sensors & Actuators A Physical, 2010, 158(2): 207-211.

[12] [12] ANDREWS N L P, LITMAN J, STROH D, et al. Near-infrared absorption detection in picolitre liquid volumes using amplified fibre loop ring-down detection[J]. Optical Fiber Technology, 2013, 19(6): 822-827.

[13] [13] ZHAO Y, CHANG J, NI J, et al. Novel gas sensor combined active fiber loop ring-down and dual wavelengths differential absorption method[J]. Optics Express, 2014, 22(9): 11244-11253.

[14] [14] ITTIARAH J V, SIDHIK S, GANGOPADHYAY T K. Refractometry using evanescent field based fiber loop ringdown spectroscopy[J]. Sensors & Actuators A Physical, 2015, 223: 61-66.

[15] [15] SUSANA, SILVA, REGINA, et al. Fiber cavity ring down and gain amplification effect[J]. Photon Sensor, 2016, 6(4): 324-327.

[16] [16] ZHOU Sheng, HAN Yan-ling, LI Bin-cheng. Detection of trace water vapor by cavity ring down spectroscopy with 5.2 μm quantum cascade laser[J].Spectroscopy and Spectral Analysis, 2016, 36(12): 3848-3852.

[17] [17] TU Xiao-bo, CHEN Shuang, SU Tie, et al. Uncertainty analysis of OH concentration measurement by optical cavity ring down spectroscopy[J]. Infrared and Laser Engineering, 2017, 46(2): 0239002.

[18] [18] SHANG Qiu-feng, MAO Xun, ZHANG Lixin, et al. Research on a novel Rayleigh BOTDA system[J]. Infrared and Laser Engineering, 2017, 46(1): 0120001.

[19] [19] WILKES A, WILLIAMS D. Measurement of humidity[J]. Anaesthesia & Intensive Care Medicine, 2015, 16(3): 128-131.