A High Sensitivity Micro-Ring Humidity Sensor Based on U-Shaped Waveguide Coupled Single Micro-Ring Structure
LI Zhi-quan1, WANG Lu-na1, LI Xin2, ZHANG Xin1
1. College of Electrical Engineering, Yanshan University, Qinghuangdao 066004, China 2. Control and Simnltion Center, Harbin Institute of Technology, Harbin 150080，China
Abstract：The paper proposes a novel high sensitivity humidity sensor based on a U-shaped waveguide-coupled single micro-ring, Polyimide is used as the wet material, the refractive index of humidity-sensing part changes as relative humidity changes, thus leading to a obvious peak drift. The transfer function of the structure is derived basing on transfer matrix method and the paper mainly discusses the influence on the output spectrum with different humidity-sensing parts. Through the theoretical simulation of Matlab, the whole structure of U-shaped waveguide coupled single micro-ring is proved to be the best humidity-sensing part. The free spectral range (FSR) will be doubled compared to the traditional single micro ring structure while the length between the two coupling points of the U-shaped waveguide is an integer multiple of circumference of the micro-ring. When the relative humidity of external environment changes from 10%RH to 100%RH, the output spectrum appears a obvious drift from 0.027 to 0.191 μm and the sensitivity reaches up to 0.001 8 μm/%RH. Compared to FBG humidity sensor with high sensitivity, the sensitivity in this article is increased by 10 to 100 times, achieving a high sensitivity in the sense of humidity when the wide range of filter frequency selection is taken into account.
Key words：U-shaped waveguide-coupled single micro-ring structure;Transfer matrix method;Humidity sensor;Sensitivity;FSR
李志全1，王禄娜1，李 欣2，张 鑫1. 基于U型波导耦合单微环结构的高灵敏度湿度传感器 [J]. 光谱学与光谱分析, 2015, 35(02): 563-567.
LI Zhi-quan1, WANG Lu-na1, LI Xin2, ZHANG Xin1. A High Sensitivity Micro-Ring Humidity Sensor Based on U-Shaped Waveguide Coupled Single Micro-Ring Structure . SPECTROSCOPY AND SPECTRAL ANALYSIS, 2015, 35(02): 563-567.
[1] Huang X F, Sheng D R, Cen K F, et al. Sensors Actuat., 2007, 127(2): 518. [2] Lourdes Alwis, Tong Sun, Kenneth V Grattan. IEEE Sensors Journal, 2013, 13(2): 767. [3] ZHANG Bin, MAO Lu-hong, XIE Sheng, et al(张 彬, 毛陆虹, 谢 生，等). Acta Optica Sinica(光学学报), 2010, 30(2): 537. [4] Li Q, Liu F, Zhang Z, et al. J. Lightw. Technol., 2008, 26(23): 3744. [5] Liang D, Fiorentino M, Srinivasan S, et al. IEEE Journal of Selected Topics in Quantum Electronics, 2011, 17(6): 1528. [6] Deng Honggui, Yang Bingchu, Chen Zhou, et al. Int. J. Electrochem. Sci., 2012，(7): 8205. [7] Mo Wenqin, Wu Huaming, Gao Dingshan, et al. Chinese Optics Letters, 2009, 7(9): 798. [8] Bhola B, Steier W H. IEEE Sensors Journal, 2007, 7(12): 1759. [9] LI Zhi-quan, LI Xiao-yun, SUN Yu-chao, et al(李志全, 李晓云, 孙宇超，等). Acta Optica Sinica(光学学报), 2012, 32(7): 0723001. [10] Shibata H, Ito M, Asakursa M, et al. Instrumentation and Measurement, 1996, 45(2): 564.
