{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,16]],"date-time":"2026-04-16T16:28:46Z","timestamp":1776356926521,"version":"3.51.2"},"reference-count":21,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2016,2,24]],"date-time":"2016-02-24T00:00:00Z","timestamp":1456272000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>We propose a novel non-contact optical fiber displacement sensor. It uses a radio frequency (RF) interrogation technique which is based on bidirectional modulation of a Mach-Zehnder electro-optical modulator (MZ-EOM). The displacement is measured from the free spectral range (FSR) which is determined by the dip frequencies of the modulated MZ-EOM transfer function. In experiments, the proposed sensor showed a sensitivity of 456 kHz\/mm or 1.043 kHz\/V in a measurement range of 7 mm. The displacement resolution of the proposed sensor depends on the linewidth and the power of the optical source. Resolution better than 0.05 \u03bcm would be achieved if an optical source which has a linewidth narrower than 1.5 nm and a received power larger than \u221236 dBm is used. Also, the multiplexing characteristic of the proposed sensor was experimentally validated.<\/jats:p>","DOI":"10.3390\/s16030277","type":"journal-article","created":{"date-parts":[[2016,2,24]],"date-time":"2016-02-24T17:11:42Z","timestamp":1456333902000},"page":"277","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":11,"title":["An Optical Fiber Displacement Sensor Using RF Interrogation Technique"],"prefix":"10.3390","volume":"16","author":[{"given":"Hyeon-Ho","family":"Kim","sequence":"first","affiliation":[{"name":"Department of Electrical Engineering and Smart Grid Research Center, Chonbuk National University, 567 Baekje-daero, Deokjin-gu, Jeonju 54896, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0288-7517","authenticated-orcid":false,"given":"Sang-Jin","family":"Choi","sequence":"additional","affiliation":[{"name":"Department of Electrical Engineering and Smart Grid Research Center, Chonbuk National University, 567 Baekje-daero, Deokjin-gu, Jeonju 54896, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Keum","family":"Jeon","sequence":"additional","affiliation":[{"name":"Wind Valley Co. Ltd., 4 Yulchonsan-daero, Haeryong-myeon, Suncheon 58025, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8926-9740","authenticated-orcid":false,"given":"Jae-Kyung","family":"Pan","sequence":"additional","affiliation":[{"name":"Department of Electrical Engineering and Smart Grid Research Center, Chonbuk National University, 567 Baekje-daero, Deokjin-gu, Jeonju 54896, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2016,2,24]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"322","DOI":"10.1109\/7361.983472","article-title":"An overview and a contribution to the optical measurement of linear displacement","volume":"1","author":"Postolache","year":"2001","journal-title":"IEEE Sens. J."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"837","DOI":"10.1109\/LPT.2014.2308327","article-title":"M-Z interferometer constructed by two S-bend fibers for displacement and force measurements","volume":"26","author":"Chen","year":"2014","journal-title":"IEEE Photon. Tech. Lett."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"2354","DOI":"10.1109\/LPT.2013.2285160","article-title":"High-sensitivity displacement sensor based on a bent fiber Mach-Zehnder interferometer","volume":"25","author":"Chen","year":"2013","journal-title":"IEEE Photon. Tech. Lett."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"136","DOI":"10.1016\/j.optcom.2014.11.016","article-title":"Simultaneous measurement of displacement and temperature based on thin-core fiber modal interferometer","volume":"340","author":"Wu","year":"2013","journal-title":"Opt. Commun."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"168","DOI":"10.1016\/j.sna.2014.04.034","article-title":"Improved design of slow light interferometer and its application in FBG displacement sensor","volume":"214","author":"Zhang","year":"2014","journal-title":"Sens. Actuators A: Phys."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"3752","DOI":"10.1109\/JLT.2013.2288455","article-title":"Slow-light and enhanced sensitivity in a displacement sensor using a lossy fiber-based ring resonator","volume":"31","author":"Bravo","year":"2013","journal-title":"IEEE J. Lightwave Tech."},{"key":"ref_7","unstructured":"Mi, H.K., and Nan, Q.M. (2011, January 7\u201310). Study on magnetic coupling FBG displacement sensor. Proceedings of the 2011 International Conference on Mechatronics and Automation (ICMA), Beijing, China."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"128","DOI":"10.1007\/s13320-015-0220-9","article-title":"Study on the non-contact FBG vibration sensor and its application","volume":"5","author":"Li","year":"2015","journal-title":"Photon. Sens."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"441","DOI":"10.1364\/AOP.4.000441","article-title":"Optical methods for distance and displacement measurements","volume":"4","author":"Berkovic","year":"2012","journal-title":"Adv. Opt. Photon."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"333","DOI":"10.1016\/j.measurement.2013.11.007","article-title":"A review of recent developed and applications of plastic fiber optic displacement sensors","volume":"48","author":"Yang","year":"2014","journal-title":"Measurement"},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Casalicchio, M.L., Neri, A., Perrone, G., Tosi, D., and Vallan, A. (2009, January 5\u20137). Non-contact low-cost fiber distance sensor with compensation of target reflectivity. Proceedings of the 2009 Instrumentation and Measurement Technology Conference (I2MTC\u201909), Singapore.","DOI":"10.1109\/IMTC.2009.5168724"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"1389","DOI":"10.1109\/TIM.2010.2040934","article-title":"Displacement and acceleration measurements in vibration tests using a fiber optic sensor","volume":"59","author":"Vallan","year":"2010","journal-title":"IEEE Trans. Inst. Meas."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"67","DOI":"10.1016\/j.sna.2014.09.014","article-title":"Theoretical and experimental study of self-reference intensity-modulated plastic fibre optic linear array displacement sensor","volume":"222","author":"Yang","year":"2015","journal-title":"Sens. Actuators A: Phys."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"124","DOI":"10.1016\/j.optlastec.2014.10.016","article-title":"Differential reflective fiber-optic angular displacement sensor","volume":"68","author":"Shan","year":"2013","journal-title":"Optics Laser Tech."},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Jackson, D.A., Posada-Roman, J.E., and Garcia-souto, J.A. (2014, January 2\u20135). New topologies for fiber laser non-contact vibrometers. Proceedings of the 2014 IEEE Sensors, Valencia, Spain.","DOI":"10.1109\/ICSENS.2014.6985307"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"159","DOI":"10.1016\/j.optlastec.2014.07.019","article-title":"Light intensity fibre optic sensor for MEMS displacement and vibration metrology","volume":"65","author":"Kunicki","year":"2015","journal-title":"Optics Laser Tech."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"379","DOI":"10.1109\/LPT.2014.2375651","article-title":"Long-range interferometric displacement sensing with tapered optical fiber tips","volume":"27","author":"Villatoro","year":"2015","journal-title":"IEEE Phton. Tech. Lett."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"5388","DOI":"10.1109\/JSEN.2015.2426685","article-title":"Non-contact optical displacement sensor using an adiabatic U-shaped tapered fiber","volume":"15","author":"Razak","year":"2015","journal-title":"IEEE Sens. J."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"1145","DOI":"10.1109\/LPT.2002.1021997","article-title":"Optical fiber chromatic dispersion measurement using bidirectional modulation of an optical intensity modulator","volume":"14","author":"Jeon","year":"2002","journal-title":"IEEE Photon. Tech. Lett."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"8403","DOI":"10.3390\/s130708403","article-title":"Novel RF interrogation of a fiber Bragg grating sensor using bidirectional modulation of a Mach-Zehnder electro-optical modulator","volume":"13","author":"Choi","year":"2013","journal-title":"Sensors"},{"key":"ref_21","doi-asserted-by":"crossref","unstructured":"Kim, H.H., Choi, S.J., Jeon, K.S., and Pan, J.K. (2015, January 20\u201322). An implementation of non-contact optical fiber displacement sensor using bidirectional modulation of a Mach-Zehnder electro-optical modulator. Proceedings of the 5th Asia-Pacific Optical Sensors Conference (5th APOS), Jeju, Korea.","DOI":"10.1117\/12.2184397"}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/16\/3\/277\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T19:19:34Z","timestamp":1760210374000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/16\/3\/277"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2016,2,24]]},"references-count":21,"journal-issue":{"issue":"3","published-online":{"date-parts":[[2016,3]]}},"alternative-id":["s16030277"],"URL":"https:\/\/doi.org\/10.3390\/s16030277","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2016,2,24]]}}}