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光纤法布里-珀罗干涉温度压力传感技术研究进展

李自亮 廖常锐 刘申 王义平

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光纤法布里-珀罗干涉温度压力传感技术研究进展

李自亮, 廖常锐, 刘申, 王义平

Research progress of in-fiber Fabry-Perot interferometric temperature and pressure sensors

Li Zi-Liang, Liao Chang-Rui, Liu Shen, Wang Yi-Ping
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  • 光纤法布里-珀罗干涉温度和压力传感器具有灵敏度高、制作简单、成本低、体积小和抗电磁干扰能力强等优点,已被广泛应用于军事和民用领域.在某些环境恶劣,如具有强电磁干扰和腐蚀性,或提供给传感器的安装空间非常有限的特殊工业领域,微型光纤温度和压力传感器发挥着重要的作用,国内外诸多高校、科研院所都在对其进行研究.本文综述了光纤法布里-珀罗干涉仪的基本原理、制备技术、及其压力和温度传感应用的研究进展.详细介绍了湿法化学腐蚀制备法、电弧放电制备法、飞秒激光制备法、聚合物辅助制备法等常见光纤法布里-珀罗腔传感器的制作工艺,分析了不同制作工艺的优缺点;详细介绍了光纤法布里-珀罗干涉仪在温度传感、压力传感和温压一体传感领域的应用;最后对光纤法布里-珀罗干涉温度压力传感器的发展进行了总结和展望.
    Optical fiber sensors based on Fabry-Perot interferometer (FPI) have attracted intensive attention for sensing applications in temperature and pressure measurement, owing to their compact, small size, fast responses, high resolution, high sensitivity, good stability, and resistance to electromagnetic interference. It's known that the in-fiber optic interferometers based on single-mode fibers can exhibit compact structures, easy fabrication and low cost. In this paper, firstly, the basic principle of in-fiber FPIs is introduced. Secondly, we review several kinds of typical in-fiber FPIs formed in single-mode fibers fabricated with different post-processing techniques, such as chemical etching, arc discharge, femtosecond laser micromachining, and polymer coating, etc. Finally, the optical sensors based on in-fiber FPIs, with a capability of simultaneous multi-parameter sensing of temperature and pressure, are summarized and prospected.
      通信作者: 王义平, ypwang@szu.edu.cn
    • 基金项目: 国家自然科学基金(批准号:61635007,61425007,61377090,61575128)、广东省自然科学基金(批准号:2014A030308007,2014B050504010,2015B010105007,2015A030313541)、深圳市科技创新委员会项目(批准号:GJHZ2015031309375575,JCYJ20160520163134575,JCYJ20160427104925452)和珠江学者项目资助的课题.
      Corresponding author: Wang Yi-Ping, ypwang@szu.edu.cn
    • Funds: Project supported by the National Natural Science Foundation of China (Grant Nos. 61635007, 61425007 61377090, 61575128), the Guangdong Natural Science Foundation, China (Grant Nos. 2014A030308007, 2014B050504010, 2015B010105007, 2015A030313541), the Science and Technology Innovation Commission of Shenzhen, China (Grant Nos. GJHZ20150313093755757, JCYJ20160520163134575, JCYJ20160427104925452), and Pearl River Scholar Fellowships, China.
    [1]

    Lin Z H, Li C F, Liu J C 2011Optical Communication Technology 7 4 (in Chinese)[林之华, 李朝锋, 刘甲春2011光通信技术7 4]

    [2]

    Meng Z, Hu Y M, Yao Q, Song Z Q, Zhang Z H 2007Journal of North University of China (Social Science Edition) 23 98 (in Chinese)[孟洲, 胡永明, 姚琼, 宋章启, 张振慧2007中北大学学报23 98]

    [3]

    Wang Y P, Chen J P, Li X W, Zhou J Q, Shen H, Shi C H, Zhang X H, Hong J X, Ye A L 2005Acta Phys. Sin. 54 4782 (in Chinese)[王义平, 陈建平, 李新碗, 周俊鹤, 沈浩, 施长海, 张晓红, 洪建勋, 叶爱伦2005 54 4782]

    [4]

    Zhang G J 2005Ph. D Dissertation (Dalian:Dalian University of Technology) (in Chinese)[张桂菊2005博士学位论文(大连:大连理工大学)]

    [5]

    Liu S, Wang Y P, Liao C R, et al. 2014Opt. Lett. 39 2121

    [6]

    Liao C, Wang Q, Xu L, et al. 2016Appl. Opt. 55 1525

    [7]

    Wang Y P, Rao Y J, Ran Z L, Zhu T 2003Acta Phys. Sin. 52 1432 (in Chinese)[王义平, 饶云江, 冉曾令, 朱涛2003 52 1432]

    [8]

    Lee C, Taylor H 1988Electron. Lett. 24 193

    [9]

    Murphy K A, Gunther M F, Vengsarkar A M, Claus R O 1991Conf on Fiber Optic Smart Structures and Skins 4 Boston, MA Sep. 5-6, 1991 p134

    [10]

    Donlagic D, Cibula E 2005Opt. Lett. 30 2071

    [11]

    Zhu Y Z, Cooper K L, Pickrell G R, Wang A 2006J. Lightwave Technol. 24 861

    [12]

    Pevec S, Donlagic D 2012Appl. Opt. 51 4536

    [13]

    Poeggel S, Duraibabu D, Tosi D, et al. 2015J. Biomed. Opt. 20 037005

    [14]

    Ma J, Ju J, Jin L, Jin W 2011IEEE Photonics Technology Letters 23 1561

    [15]

    Liao C R, Liu S, Xu L, et al. 2014Opt. Lett. 39 2827

    [16]

    Liu S, Yang K M, Wang Y P, et al. 2015Sci. Rep. 5 7624

    [17]

    Rao Y J, Deng M, Duan D W, et al. 2007Opt. Express 15 14123

    [18]

    Wei T, Han Y K, Tsai H L, Xiao H 2008Opt. Lett. 33 536

    [19]

    Tang J, Yin G L, Liao C R, et al. 2015IEEE Photon. J. 7 1

    [20]

    Hill G C, Melamud R, Declercq F E, et al. 2007Sens. Actuator A:Phys. 138 52

    [21]

    Nesson S, Yu M A, Zhang X M, Hsieh A H 2008J. Biomed. Opt. 13 044040

    [22]

    Sun B, Wang Y P, Qu J L, et al. 2015Opt. Express 23 1906

    [23]

    Jia C Y 2009M. S. Dissertation (Dalian:Dalian University of Technology) (in Chinese)[贾春艳2009硕士学位论文(大连:大连理工大学)]

    [24]

    Li C 2013M. S. Dissertation (Chengdu:University of Electronic Science and Technology) (in Chinese)[李成2013硕士学位论文(成都:电子科技大学)]

    [25]

    Bi W H, Wang X, Lang L Y 2002Journal of OptoelectronicsLaser 13 1316 (in Chinese)[毕卫红, 王昕, 郎利影2002光电子激光13 1316]

    [26]

    Kuske A, Robertson G 1979Photoelastic Stress Analysis (Shanghai:Shanghai Science and Technology Press) (in Chinese)[柯斯克, 罗伯逊1979光弹性应力分析(上海:上海科学技术出版社)]

    [27]

    Sun S H, Wang T Y, Xu Y 2000Optical Fiber Measurement and Sensing Technology (Harbin:Harbin Institute of Technology Press) (in Chinese)[孙圣和, 王廷云, 徐颖2000光纤测量与传感技术(哈尔滨:哈尔滨工业大学出版社)]

    [28]

    Hao Z Y 2005M. S. Dissertation (Shijiazhuang:Hebei University of Technology) (in Chinese)[郝子宇2005硕士学位论文(石家庄:河北工业大学)]

    [29]

    Kern W, Yang G G 1987Microelectronics 3 11 (in Chinese)[科恩, 杨功铬1987微电子学3 11]

    [30]

    Wang Y P, Tang J, Ying G L, Zhong X Y, Liao C R 2015J. Vibration, Measurement Diagnosis 35 809 (in Chinese)[王义平, 唐剑, 尹国路, 钟晓勇, 廖常锐2015振动测试与诊断35 809]

    [31]

    Han B, Gao C 2012Metrology Measurement Technology 32 5 (in Chinese)[韩冰, 高超2012计测技术32 5]

    [32]

    Zhang D Z, Hu G Q, Chen C W 2009 Instrument Technique and Sensor 114(in Chinese)[张冬至, 胡国清, 陈昌伟2009仪表技术与传感器114]

    [33]

    Yang K M, He J, Wang Y, et al. 2015IEEE Photonics J. 7 1

    [34]

    Frazao O, Silva S F, Viegas J, et al. 2010Meas. Sci. Technol. 2 1

    [35]

    Kou J L, Feng J, Ye L F 2010Opt. Express 18 14245

    [36]

    Zhu J J, Zhang A P, Xia T H 2010IEEE Sens. J. 10 1415

    [37]

    Ke T, Zhu T, Rao Y J, Xu M, Duan D W 2010Infrared and Laser Engineering 39 106 (in Chinese)[柯涛, 朱涛, 饶云江, 徐敏, 段德稳2010红外与激光工程39 106]

    [38]

    Rong Q Z, Sun H, Qiao X G 2012J. Opt. 14 045002

    [39]

    Jia P G, Wang D H 2013Chin. Opt. Lett. 11 040601

    [40]

    Davis C M 1988US Patent 4755668

    [41]

    Andrews J P, Pulfrey R E 1999US Patent 5907403

    [42]

    Kim M G, Park J, Kang S W 1997Smart Electronics and MEMS Adelaide, SA, Australia 11-13 Dec. 1997 p347

    [43]

    Zetterlind V E, Watkins S E, Spoltman M W 2003IEEE Sens. J. 3 393

    [44]

    Aref S, Latifi H, Zibaii M, Afshari M 2007Optics Communications 269 322

    [45]

    Wang Y, Wang D N, Wang C 2013Opt. Express 21 14084

    [46]

    Jiang M, Gerhard E 2001Sensors and Actuators A:Physical 88 41

    [47]

    Xiao G Z, Adnet A, Zhang Z 2005Sensors and Actuators A:Physical 118 177

    [48]

    Lai C W, Yur J P, Liao C C, Lo Y L 2011Recent Patents on Signal Processing 1 48

    [49]

    Reinsch T, Blcher G, Milsch H 2012arXiv preprint arXiv 55 55

    [50]

    Zhang Y, Yuan L, Lan X 2013Opt. Lett. 38 4609

    [51]

    Dai L, Wang M, Cai D 2013IEEE Photonics Technology Letters 25 2505

    [52]

    Taylor H F, Kao T W, Gardner J, et al. 2001US Patent 6281976

    [53]

    Schmidt S 2008US Patent 7423762

    [54]

    Lopushansky R L, Berthold J W 2009US Patent 7492463

    [55]

    Bremer K, Leen G, Lewis E 2014US Patent 8764678

    [56]

    Yu Q X, Wang X N, Song S D, Zhao Y W, Cui S B 2007J. Optoelectronics Laser 18 299 (in Chinese)[于清旭, 王晓娜, 宋世德, 赵业卫, 崔士斌2007光電子18 299]

    [57]

    Shi Y 2010Oil Drilling Product Technology 32 70 (in Chinese)[石艺2010石油钻采工艺32 70]

    [58]

    Xu B, Liu Y M, Wang D N, Li J Q 2016J. Lightwave Technol. 34 4920

    [59]

    Wu C, Fu H, Qureshi K K, Guan B O, Tam H Y 2011Opt. Lett. 36 412

  • [1]

    Lin Z H, Li C F, Liu J C 2011Optical Communication Technology 7 4 (in Chinese)[林之华, 李朝锋, 刘甲春2011光通信技术7 4]

    [2]

    Meng Z, Hu Y M, Yao Q, Song Z Q, Zhang Z H 2007Journal of North University of China (Social Science Edition) 23 98 (in Chinese)[孟洲, 胡永明, 姚琼, 宋章启, 张振慧2007中北大学学报23 98]

    [3]

    Wang Y P, Chen J P, Li X W, Zhou J Q, Shen H, Shi C H, Zhang X H, Hong J X, Ye A L 2005Acta Phys. Sin. 54 4782 (in Chinese)[王义平, 陈建平, 李新碗, 周俊鹤, 沈浩, 施长海, 张晓红, 洪建勋, 叶爱伦2005 54 4782]

    [4]

    Zhang G J 2005Ph. D Dissertation (Dalian:Dalian University of Technology) (in Chinese)[张桂菊2005博士学位论文(大连:大连理工大学)]

    [5]

    Liu S, Wang Y P, Liao C R, et al. 2014Opt. Lett. 39 2121

    [6]

    Liao C, Wang Q, Xu L, et al. 2016Appl. Opt. 55 1525

    [7]

    Wang Y P, Rao Y J, Ran Z L, Zhu T 2003Acta Phys. Sin. 52 1432 (in Chinese)[王义平, 饶云江, 冉曾令, 朱涛2003 52 1432]

    [8]

    Lee C, Taylor H 1988Electron. Lett. 24 193

    [9]

    Murphy K A, Gunther M F, Vengsarkar A M, Claus R O 1991Conf on Fiber Optic Smart Structures and Skins 4 Boston, MA Sep. 5-6, 1991 p134

    [10]

    Donlagic D, Cibula E 2005Opt. Lett. 30 2071

    [11]

    Zhu Y Z, Cooper K L, Pickrell G R, Wang A 2006J. Lightwave Technol. 24 861

    [12]

    Pevec S, Donlagic D 2012Appl. Opt. 51 4536

    [13]

    Poeggel S, Duraibabu D, Tosi D, et al. 2015J. Biomed. Opt. 20 037005

    [14]

    Ma J, Ju J, Jin L, Jin W 2011IEEE Photonics Technology Letters 23 1561

    [15]

    Liao C R, Liu S, Xu L, et al. 2014Opt. Lett. 39 2827

    [16]

    Liu S, Yang K M, Wang Y P, et al. 2015Sci. Rep. 5 7624

    [17]

    Rao Y J, Deng M, Duan D W, et al. 2007Opt. Express 15 14123

    [18]

    Wei T, Han Y K, Tsai H L, Xiao H 2008Opt. Lett. 33 536

    [19]

    Tang J, Yin G L, Liao C R, et al. 2015IEEE Photon. J. 7 1

    [20]

    Hill G C, Melamud R, Declercq F E, et al. 2007Sens. Actuator A:Phys. 138 52

    [21]

    Nesson S, Yu M A, Zhang X M, Hsieh A H 2008J. Biomed. Opt. 13 044040

    [22]

    Sun B, Wang Y P, Qu J L, et al. 2015Opt. Express 23 1906

    [23]

    Jia C Y 2009M. S. Dissertation (Dalian:Dalian University of Technology) (in Chinese)[贾春艳2009硕士学位论文(大连:大连理工大学)]

    [24]

    Li C 2013M. S. Dissertation (Chengdu:University of Electronic Science and Technology) (in Chinese)[李成2013硕士学位论文(成都:电子科技大学)]

    [25]

    Bi W H, Wang X, Lang L Y 2002Journal of OptoelectronicsLaser 13 1316 (in Chinese)[毕卫红, 王昕, 郎利影2002光电子激光13 1316]

    [26]

    Kuske A, Robertson G 1979Photoelastic Stress Analysis (Shanghai:Shanghai Science and Technology Press) (in Chinese)[柯斯克, 罗伯逊1979光弹性应力分析(上海:上海科学技术出版社)]

    [27]

    Sun S H, Wang T Y, Xu Y 2000Optical Fiber Measurement and Sensing Technology (Harbin:Harbin Institute of Technology Press) (in Chinese)[孙圣和, 王廷云, 徐颖2000光纤测量与传感技术(哈尔滨:哈尔滨工业大学出版社)]

    [28]

    Hao Z Y 2005M. S. Dissertation (Shijiazhuang:Hebei University of Technology) (in Chinese)[郝子宇2005硕士学位论文(石家庄:河北工业大学)]

    [29]

    Kern W, Yang G G 1987Microelectronics 3 11 (in Chinese)[科恩, 杨功铬1987微电子学3 11]

    [30]

    Wang Y P, Tang J, Ying G L, Zhong X Y, Liao C R 2015J. Vibration, Measurement Diagnosis 35 809 (in Chinese)[王义平, 唐剑, 尹国路, 钟晓勇, 廖常锐2015振动测试与诊断35 809]

    [31]

    Han B, Gao C 2012Metrology Measurement Technology 32 5 (in Chinese)[韩冰, 高超2012计测技术32 5]

    [32]

    Zhang D Z, Hu G Q, Chen C W 2009 Instrument Technique and Sensor 114(in Chinese)[张冬至, 胡国清, 陈昌伟2009仪表技术与传感器114]

    [33]

    Yang K M, He J, Wang Y, et al. 2015IEEE Photonics J. 7 1

    [34]

    Frazao O, Silva S F, Viegas J, et al. 2010Meas. Sci. Technol. 2 1

    [35]

    Kou J L, Feng J, Ye L F 2010Opt. Express 18 14245

    [36]

    Zhu J J, Zhang A P, Xia T H 2010IEEE Sens. J. 10 1415

    [37]

    Ke T, Zhu T, Rao Y J, Xu M, Duan D W 2010Infrared and Laser Engineering 39 106 (in Chinese)[柯涛, 朱涛, 饶云江, 徐敏, 段德稳2010红外与激光工程39 106]

    [38]

    Rong Q Z, Sun H, Qiao X G 2012J. Opt. 14 045002

    [39]

    Jia P G, Wang D H 2013Chin. Opt. Lett. 11 040601

    [40]

    Davis C M 1988US Patent 4755668

    [41]

    Andrews J P, Pulfrey R E 1999US Patent 5907403

    [42]

    Kim M G, Park J, Kang S W 1997Smart Electronics and MEMS Adelaide, SA, Australia 11-13 Dec. 1997 p347

    [43]

    Zetterlind V E, Watkins S E, Spoltman M W 2003IEEE Sens. J. 3 393

    [44]

    Aref S, Latifi H, Zibaii M, Afshari M 2007Optics Communications 269 322

    [45]

    Wang Y, Wang D N, Wang C 2013Opt. Express 21 14084

    [46]

    Jiang M, Gerhard E 2001Sensors and Actuators A:Physical 88 41

    [47]

    Xiao G Z, Adnet A, Zhang Z 2005Sensors and Actuators A:Physical 118 177

    [48]

    Lai C W, Yur J P, Liao C C, Lo Y L 2011Recent Patents on Signal Processing 1 48

    [49]

    Reinsch T, Blcher G, Milsch H 2012arXiv preprint arXiv 55 55

    [50]

    Zhang Y, Yuan L, Lan X 2013Opt. Lett. 38 4609

    [51]

    Dai L, Wang M, Cai D 2013IEEE Photonics Technology Letters 25 2505

    [52]

    Taylor H F, Kao T W, Gardner J, et al. 2001US Patent 6281976

    [53]

    Schmidt S 2008US Patent 7423762

    [54]

    Lopushansky R L, Berthold J W 2009US Patent 7492463

    [55]

    Bremer K, Leen G, Lewis E 2014US Patent 8764678

    [56]

    Yu Q X, Wang X N, Song S D, Zhao Y W, Cui S B 2007J. Optoelectronics Laser 18 299 (in Chinese)[于清旭, 王晓娜, 宋世德, 赵业卫, 崔士斌2007光電子18 299]

    [57]

    Shi Y 2010Oil Drilling Product Technology 32 70 (in Chinese)[石艺2010石油钻采工艺32 70]

    [58]

    Xu B, Liu Y M, Wang D N, Li J Q 2016J. Lightwave Technol. 34 4920

    [59]

    Wu C, Fu H, Qureshi K K, Guan B O, Tam H Y 2011Opt. Lett. 36 412

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计量
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出版历程
  • 收稿日期:  2017-01-19
  • 修回日期:  2017-02-24
  • 刊出日期:  2017-04-05

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