{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,27]],"date-time":"2026-01-27T09:22:02Z","timestamp":1769505722495,"version":"3.49.0"},"reference-count":61,"publisher":"MDPI AG","issue":"22","license":[{"start":{"date-parts":[[2020,11,11]],"date-time":"2020-11-11T00:00:00Z","timestamp":1605052800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Russian Foundation of Basic Research","award":["19-32-90185"],"award-info":[{"award-number":["19-32-90185"]}]},{"name":"state task","award":["."],"award-info":[{"award-number":["."]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Weak fiber Bragg gratings (WFBGs) in a phase-sensitive optical time-domain reflectometer (phi-OTDR) sensor offer opportunities to significantly improve the signal-to-noise ratio (SNR) and sensitivity of the device. Here, we demonstrate the process of the signal and noise components\u2019 formation in the device reflectograms for a Rayleigh scattering phi-OTDR and a WFBG-based OTDR. We theoretically calculated the increase in SNR when using the same optical and electrical components under the same external impacts for both setups. The obtained values are confirmed on experimental installations, demonstrating an improvement in the SNR by about 19 dB at frequencies of 20, 100, and 400 Hz. In this way, the minimum recorded impact (at the threshold SNR = 10) can be reduced from 100 nm per 20 m of fiber to less than 5 nm per 20 m of fiber sensor.<\/jats:p>","DOI":"10.3390\/s20226431","type":"journal-article","created":{"date-parts":[[2020,11,11]],"date-time":"2020-11-11T19:08:28Z","timestamp":1605121708000},"page":"6431","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":26,"title":["The Sensitivity Improvement Characterization of Distributed Strain Sensors Due to Weak Fiber Bragg Gratings"],"prefix":"10.3390","volume":"20","author":[{"given":"Konstantin V.","family":"Stepanov","sequence":"first","affiliation":[{"name":"Bauman Moscow State Technical University, 2-nd Baumanskaya 5-1, 105005 Moscow, Russia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6772-1572","authenticated-orcid":false,"given":"Andrey A.","family":"Zhirnov","sequence":"additional","affiliation":[{"name":"Bauman Moscow State Technical University, 2-nd Baumanskaya 5-1, 105005 Moscow, Russia"},{"name":"Kotelnikov Institute of Radioengineering and Electronics of RAS, Mokhovaya 11-7, 125009 Moscow, Russia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0302-5687","authenticated-orcid":false,"given":"Anton O.","family":"Chernutsky","sequence":"additional","affiliation":[{"name":"Bauman Moscow State Technical University, 2-nd Baumanskaya 5-1, 105005 Moscow, Russia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Kirill I.","family":"Koshelev","sequence":"additional","affiliation":[{"name":"Bauman Moscow State Technical University, 2-nd Baumanskaya 5-1, 105005 Moscow, Russia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Alexey B.","family":"Pnev","sequence":"additional","affiliation":[{"name":"Bauman Moscow State Technical University, 2-nd Baumanskaya 5-1, 105005 Moscow, Russia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Alexey I.","family":"Lopunov","sequence":"additional","affiliation":[{"name":"Kotelnikov Institute of Radioengineering and Electronics of RAS, Mokhovaya 11-7, 125009 Moscow, Russia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5464-4034","authenticated-orcid":false,"given":"Oleg V.","family":"Butov","sequence":"additional","affiliation":[{"name":"Kotelnikov Institute of Radioengineering and Electronics of RAS, Mokhovaya 11-7, 125009 Moscow, Russia"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2020,11,11]]},"reference":[{"key":"ref_1","unstructured":"Taylor, H.F., and Lee, C.E. (1993). Apparatus and Method for Fiber Optic Intrusion Sensing. (5194847), U.S. Patent."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"2081","DOI":"10.1109\/JLT.2005.849924","article-title":"Distributed fiber-optic intrusion sensor system","volume":"23","author":"Juarez","year":"2005","journal-title":"J. Lightwave Technol."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"1968","DOI":"10.1364\/AO.46.001968","article-title":"Field test of a distributed fiber-optic intrusion sensor system for long perimeters","volume":"46","author":"Juarez","year":"2007","journal-title":"Appl. Opt."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"134","DOI":"10.1117\/12.484911","article-title":"Distributed fiberoptic pressureseismic sensor for low-cost monitoring of long perimeters","volume":"5090","author":"Choi","year":"2003","journal-title":"Proc. SPIE"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"49","DOI":"10.1117\/12.318220","article-title":"A fiber optic intrusion sensor with the configuration of an optical time domain reflectometer using coherent interference of Rayleigh backscattering","volume":"3555","author":"Park","year":"1998","journal-title":"Proc. SPIE"},{"key":"ref_6","first-page":"3243","article-title":"Distributed vibration sensor based on coherent detection of phase-OTDR","volume":"28","author":"Lu","year":"2010","journal-title":"J. Lightwave Technol."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"20459","DOI":"10.1364\/OE.20.020459","article-title":"Continuous wavelet transform for non-stationary vibration detection with phase-OTDR","volume":"20","author":"Qin","year":"2017","journal-title":"Opt. Express"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"10240","DOI":"10.1364\/OE.16.010240","article-title":"Distributed optical fiber vibration sensor based on spectrum analysis of Polarization-OTDR system","volume":"16","author":"Zhang","year":"2008","journal-title":"Opt. Express"},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"Tejedor, J., Macias-Guarasa, J., Martins, H.F., Piote, D., Pastor-Graells, J., Martin-Lopez, S., Corredera, P., and Gonzalez-Herraez, M. (2017). A novel fiber optic based surveillance system for prevention of pipeline integrity threats. Sensors, 17.","DOI":"10.3390\/s17020355"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"1052","DOI":"10.1109\/JLT.2017.2780126","article-title":"Real field deployment of a smart fiber-optic surveillance system for pipeline integrity threat detection: Architectural issues and blind field test results","volume":"36","author":"Tejedor","year":"2018","journal-title":"J. Lightwave Technol."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"13121","DOI":"10.1364\/OE.24.013121","article-title":"Single-shot distributed temperature and strain tracking using direct detection phase-sensitive OTDR with chirped pulses","volume":"24","author":"Martins","year":"2016","journal-title":"Opt. Express"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"4677","DOI":"10.1109\/JLT.2017.2756558","article-title":"Chirped-Pulse Phase-Sensitive Reflectometer Assisted by First -Order Raman Amplification","volume":"35","author":"Nuno","year":"2017","journal-title":"J. Lightwave Technol."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"5600","DOI":"10.1364\/AO.37.005600","article-title":"Interferometric optical time-domain reflectometry for distributed optical-fiber sensing","volume":"37","author":"Shatalin","year":"1998","journal-title":"Appl. Opt."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"115106","DOI":"10.1088\/1054-660X\/24\/11\/115106","article-title":"A phase-sensitive optical time-domain reflectometer with dual-pulse phase modulated probe signal","volume":"24","author":"Alekseev","year":"2014","journal-title":"Laser Phys."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"065101","DOI":"10.1088\/1054-660X\/25\/6\/065101","article-title":"A phase-sensitive optical time-domain reflectometer with dual-pulse diverse frequency probe signal","volume":"25","author":"Alekseev","year":"2015","journal-title":"Laser Phys."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"887","DOI":"10.1070\/QE2010v040n10ABEH014389","article-title":"Model of a fibreoptic phase-sensitive reflectometer and its comparison with the experiment","volume":"40","author":"Tosoni","year":"2010","journal-title":"Quantum Electron."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"012028","DOI":"10.1088\/1742-6596\/584\/1\/012028","article-title":"Experimental study of influence of nonlinear effects on phase- sensitive optical time-domain reflectometer operating range","volume":"584","author":"Nesterov","year":"2015","journal-title":"J. Phys. Conf. Ser."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"656","DOI":"10.1134\/S0030400X1910031X","article-title":"Influence of the Laser Frequency Drift in Phase-Sensitive Optical Time Domain Reflectometry","volume":"127","author":"Zhirnov","year":"2019","journal-title":"Opt. Spectrosc."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"085107","DOI":"10.1088\/1555-6611\/aac714","article-title":"Distributed temperature sensor based on a phase-sensitive optical time-domain Rayleigh reflectometer","volume":"28","author":"Nikitin","year":"2018","journal-title":"Laser Phys."},{"key":"ref_20","first-page":"46","article-title":"Use of a chirped pulse for restoring the phase in a coherent reflectometer","volume":"6","author":"Yatseev","year":"2019","journal-title":"Foton Express"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"192","DOI":"10.1111\/1365-2478.12612","article-title":"The use of multi-frequency acquisition to significantly improve the quality of fibre-optic-distributed vibration sensing","volume":"66","author":"Hartog","year":"2018","journal-title":"Geophys. Prospect."},{"key":"ref_22","unstructured":"Hartog, A.H., and Liokumovich, L.B. (2012). Phase Sensitive Coherent otdr with Multi-Frequency Interrogation. (WO2013066654 A1), U.S. Patent."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"2523","DOI":"10.1109\/LPT.2015.2468075","article-title":"Active compensation method for light source frequency drifting in Phi-OTDR sensing system","volume":"27","author":"Zhu","year":"2015","journal-title":"IEEE Photon. Technol. Lett."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"119448","DOI":"10.1109\/ACCESS.2020.3004207","article-title":"A novel DAS signal recognition method based on spatiotemporal information extraction with 1DCNNs-BiLSTM network","volume":"8","author":"Wu","year":"2020","journal-title":"IEEE Access"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"1349","DOI":"10.1109\/LPT.2015.2421354","article-title":"The development of an phi-OTDR system for quantitative vibration measurement","volume":"27","author":"Tu","year":"2015","journal-title":"IEEE Photon. Technol. Lett."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"1884","DOI":"10.1109\/LPT.2015.2444419","article-title":"Distributed Strain and Vibration Sensing System Based on Phase-Sensitive OTDR","volume":"27","author":"Zhou","year":"2015","journal-title":"IEEE Photon. Technol. Lett."},{"key":"ref_27","unstructured":"Kersey, A.D., Dandridge, A., and Vohra, S.T. (2001). Coherent Reflectometric Fiber Bragg Grating Sensor Array. (US6285806B1), U.S. Patent."},{"key":"ref_28","doi-asserted-by":"crossref","unstructured":"Popov, S.M., Butov, O.V., Kolosovskiy, A.O., Voloshin, V.V., Vorob\u2019ev, I.L., Vyatkin, M.Y., Fotiadi, A.A., and Chamorovskiy, Y.K. (2017, January 22\u201325). Optical fibres with arrays of FBG: Properties and application. Proceedings of the 2017 Progress in Electromagnetics Research Symposium\u2013Spring (PIERS), St. Petersburg, Russia.","DOI":"10.1109\/PIERS.2017.8261997"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"4829","DOI":"10.1364\/OE.23.004829","article-title":"Ultra-weak FBG and its refractive index distribution in the drawing optical fiber","volume":"23","author":"Guo","year":"2015","journal-title":"Opt. Express"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"639","DOI":"10.1134\/S106422691606022X","article-title":"Optical Fiber with Distributed Bragg-Type Reflector","volume":"61","author":"Zaitsev","year":"2016","journal-title":"J. Commun. Technol. Electron."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"70","DOI":"10.1109\/LPT.2010.2089676","article-title":"A quasi-distributed sensing network with time-division-multiplexed fiber Bragg gratings","volume":"23","author":"Wang","year":"2011","journal-title":"IEEE Photon. Technol. Lett."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"1406","DOI":"10.1109\/JLT.2014.2305714","article-title":"A Novel Interrogation System for Large Scale Sensing Network with Identical Ultra-Weak Fiber Bragg Gratings","volume":"32","author":"Hu","year":"2014","journal-title":"J. Lightwave Technol."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"29038","DOI":"10.1364\/OE.23.029038","article-title":"Distributed OTDR-interferometric sensing network with identical ultra-weak fiber bragg gratings","volume":"23","author":"Wang","year":"2015","journal-title":"Opt. Express"},{"key":"ref_34","first-page":"6800511","article-title":"SNR enhanced distributed vibration fiber sensing system employing polarization OTDR and ultraweak FBGs","volume":"7","author":"Wang","year":"2015","journal-title":"IEEE Photon. J."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"962003","DOI":"10.1117\/12.2192682","article-title":"The performance limit of \u03a6-OTDR sensing system enhanced with ultra-weak fiber Bragg grating array","volume":"9620","author":"Xia","year":"2015","journal-title":"Proc. SPIE"},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"4775","DOI":"10.1109\/JLT.2015.2477243","article-title":"Improved \u03a6-OTDR sensing system for high-precision dynamic strain measurement based on ultra-weak fiber bragg grating array","volume":"33","author":"Zhu","year":"2015","journal-title":"J. Lightwave Technol."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"054103","DOI":"10.1117\/1.OE.55.5.054103","article-title":"Enhanced \u03a6-OTDR system for quantitative strain measurement based on ultra-weak fiber Bragg grating array","volume":"55","author":"Zhang","year":"2016","journal-title":"Opt. Eng."},{"key":"ref_38","first-page":"1","article-title":"A high performance distributed optical fiber sensor based on \u03a6-OTDR for dynamic strain measurement","volume":"9","author":"Zhang","year":"2017","journal-title":"IEEE Photon. J."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"146","DOI":"10.1007\/s13320-018-0410-3","article-title":"Distributed weak fiber Bragg grating vibration sensing system based on 3 \u00d7 3 fiber coupler","volume":"8","author":"Li","year":"2018","journal-title":"Photon. Sens."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"17437","DOI":"10.1364\/OE.26.017437","article-title":"Simultaneous distributed static and dynamic sensing based on ultra-short fiber Bragg gratings","volume":"26","author":"Li","year":"2018","journal-title":"Opt. Express"},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"677","DOI":"10.1109\/LPT.2018.2811411","article-title":"Interrogation of ultra-weak FBG array using double-pulse and heterodyne detection","volume":"30","author":"Liu","year":"2018","journal-title":"IEEE Photon. Technol. Lett."},{"key":"ref_42","doi-asserted-by":"crossref","unstructured":"Tang, J., Li, L., Guo, H., Yu, H., Wen, H., and Yang, M. (2017, January 24\u201328). Distributed acoustic sensing system based on continuous wide-band ultra-weak fiber Bragg grating array. Proceedings of the 2017 25th Optical Fiber Sensors Conference (OFS), Jeju, Korea.","DOI":"10.1117\/12.2262314"},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"2700","DOI":"10.1109\/JLT.2018.2889306","article-title":"An Enhanced Distributed Acoustic Sensor Based on UWFBG and Self-Heterodyne Detection","volume":"37","author":"Shan","year":"2019","journal-title":"J. Lightwave Technol."},{"key":"ref_44","doi-asserted-by":"crossref","unstructured":"Liu, T., Li, H., Ai, F., Wang, J., Fan, C., Luo, Y., Yan, Z., Liu, D., and Sun, Q. (2019, January 3\u20137). Ultra-high Resolution Distributed Strain Sensing based on Phase-OTDR. Proceedings of the 2019 Optical Fiber Communications Conference and Exhibition (OFC), San Diego, CA, USA, USA.","DOI":"10.1364\/OFC.2019.Th2A.16"},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"101995","DOI":"10.1016\/j.yofte.2019.101995","article-title":"A visibility enhanced broadband phase-sensitive OTDR based on the UWFBG array and frequency-division-multiplexing","volume":"53","author":"Zhang","year":"2019","journal-title":"Opt. Fiber Technol."},{"key":"ref_46","first-page":"087103","article-title":"Effects of weak fiber Bragg gratings on a distributed vibration sensing system based on phase-sensitive optical time-domain reflectometry","volume":"58","author":"Lee","year":"2019","journal-title":"Opt. Eng."},{"key":"ref_47","doi-asserted-by":"crossref","unstructured":"Gan, W., Li, S., Li, Z., and Sun, L. (2019). Identification of ground intrusion in underground structures based on distributed structural vibration detected by ultra-weak FBG sensing technology. Sensors, 19.","DOI":"10.3390\/s19092160"},{"key":"ref_48","doi-asserted-by":"crossref","unstructured":"Hicke, K., Eisermann, R., and Chruscicki, S. (2019). Enhanced distributed fiber optic vibration sensing and simultaneous temperature gradient sensing using traditional C-OTDR and structured fiber with scattering dots. Sensors, 19.","DOI":"10.3390\/s19194114"},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"103485","DOI":"10.1016\/j.rinp.2020.103485","article-title":"Combined Frequency and Phase domain time-gated reflectometry based on a fiber with reflection points for absolute measurements","volume":"19","author":"Yatseev","year":"2020","journal-title":"Results Phys."},{"key":"ref_50","doi-asserted-by":"crossref","unstructured":"Wang, Z., Lu, B., Zheng, H., Ye, Q., Pan, Z., Cai, H., Qu, R., Fang, Z., and Zhao, H. (2017, January 24\u201328). Novel railway-subgrade vibration monitoring technology using phase-sensitive OTDR. Proceedings of the 2017 25th Optical Fiber Sensors Conference (OFS), Jeju, Korea.","DOI":"10.1117\/12.2265169"},{"key":"ref_51","unstructured":"(2020, October 23). FiberPatrol FP1150. Available online: https:\/\/senstar.com\/products\/buried-sensors\/fiberpatrol-fp1150-for-pipeline-tpi\/."},{"key":"ref_52","unstructured":"(2020, October 23). Perimeter Intrusion Detection and Security. Available online: https:\/\/www.optasense.com\/wp-content\/uploads\/2017\/02\/Perimeter-Intrusion-Detection-and-Security_Brochure_A4_Digital.pdf."},{"key":"ref_53","unstructured":"Desurvire, E. (1994). Erbium-Doped Fiber Amplifiers: Principle and Applications, John Wiley and Sons. Inc."},{"key":"ref_54","doi-asserted-by":"crossref","first-page":"872","DOI":"10.1364\/OL.38.000872","article-title":"Modulation instability-induced fading in phase-sensitive optical time-domain reflectometry","volume":"38","author":"Martins","year":"2013","journal-title":"Opt. Lett."},{"key":"ref_55","doi-asserted-by":"crossref","first-page":"1127","DOI":"10.1070\/QEL17157","article-title":"Optical fibres and fibre tapers with an array of Bragg gratings","volume":"49","author":"Popov","year":"2019","journal-title":"Quantum Electron."},{"key":"ref_56","doi-asserted-by":"crossref","first-page":"4645","DOI":"10.1364\/AO.53.004645","article-title":"Influences of laser source on phase sensitivity optical time-domain reflectometer-based distributed intrusion sensor","volume":"53","author":"Zhong","year":"2014","journal-title":"Appl. Opt."},{"key":"ref_57","doi-asserted-by":"crossref","unstructured":"Kowarik, S., Hussels, M.T., Chruscicki, S., M\u00fcnzenberger, S., L\u00e4mmerhirt, A., Pohl, P., and Schubert, M. (2020). Fiber Optic Train Monitoring with Distributed Acoustic Sensing: Conventional and Neural Network Data Analysis. Sensors, 20.","DOI":"10.3390\/s20020450"},{"key":"ref_58","doi-asserted-by":"crossref","first-page":"036107","DOI":"10.1063\/1.4944417","article-title":"Note: Gaussian mixture model for event recognition in optical time-domain reflectometry based sensing systems","volume":"87","author":"Fedorov","year":"2016","journal-title":"Rev. Sci. Instrum."},{"key":"ref_59","doi-asserted-by":"crossref","unstructured":"Shi, Y., Wang, Y., Zhao, L., and Fan, Z. (2019). An event recognition method for \u03a6-otdr sensing system based on deep learning. Sensors, 19.","DOI":"10.3390\/s19153421"},{"key":"ref_60","doi-asserted-by":"crossref","first-page":"716","DOI":"10.1121\/1.398195","article-title":"Attenuation of sound in marine sediments: A review with emphasis on new low-frequency data","volume":"86","author":"Kibblewhite","year":"1989","journal-title":"J. Acoust. Soc. Am."},{"key":"ref_61","doi-asserted-by":"crossref","first-page":"2039","DOI":"10.1121\/1.426744","article-title":"Deduction of ground impedance from measurements of excess attenuation spectra","volume":"105","author":"Taherzadeh","year":"1999","journal-title":"J. Acoust. Soc. Am."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/20\/22\/6431\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T10:31:57Z","timestamp":1760178717000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/20\/22\/6431"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2020,11,11]]},"references-count":61,"journal-issue":{"issue":"22","published-online":{"date-parts":[[2020,11]]}},"alternative-id":["s20226431"],"URL":"https:\/\/doi.org\/10.3390\/s20226431","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2020,11,11]]}}}