{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,7]],"date-time":"2026-06-07T14:26:20Z","timestamp":1780842380413,"version":"3.54.1"},"reference-count":67,"publisher":"MDPI AG","issue":"20","license":[{"start":{"date-parts":[[2019,10,9]],"date-time":"2019-10-09T00:00:00Z","timestamp":1570579200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/100010665","name":"H2020 Marie Sk\u0142odowska-Curie Actions","doi-asserted-by":"publisher","award":["FINESSE MSCA-ITN-ETN-722509"],"award-info":[{"award-number":["FINESSE MSCA-ITN-ETN-722509"]}],"id":[{"id":"10.13039\/100010665","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100000780","name":"European Commission","doi-asserted-by":"publisher","award":["DOMINO"],"award-info":[{"award-number":["DOMINO"]}],"id":[{"id":"10.13039\/501100000780","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100012818","name":"Comunidad de Madrid","doi-asserted-by":"publisher","award":["SINFOTON2-CM: P2018\/NMT-4326"],"award-info":[{"award-number":["SINFOTON2-CM: P2018\/NMT-4326"]}],"id":[{"id":"10.13039\/100012818","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100004837","name":"Ministerio de Ciencia e Innovaci\u00f3n","doi-asserted-by":"publisher","award":["FJCI-2016-27881"],"award-info":[{"award-number":["FJCI-2016-27881"]}],"id":[{"id":"10.13039\/501100004837","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100004837","name":"Ministerio de Ciencia e Innovaci\u00f3n","doi-asserted-by":"publisher","award":["IJCI-2017-33856"],"award-info":[{"award-number":["IJCI-2017-33856"]}],"id":[{"id":"10.13039\/501100004837","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>In 2016, a novel interrogation technique for phase-sensitive (\u03a6)OTDR was mathematically formalized and experimentally demonstrated, based on the use of a chirped-pulse as a probe, in an otherwise direct-detection-based standard setup: chirped-pulse (CP-)\u03a6OTDR. Despite its short lifetime, this methodology has now become a reference for distributed acoustic sensing (DAS) due to its valuable advantages with respect to conventional (i.e., coherent-detection or frequency sweeping-based) interrogation strategies. Presenting intrinsic immunity to fading points and using direct detection, CP-\u03a6OTDR presents reliable high sensitivity measurements while keeping the cost and complexity of the setup bounded. Numerous technique analyses and contributions to study\/improve its performance have been recently published, leading to a solid, highly competitive and extraordinarily simple method for distributed fibre sensing. The interesting sensing features achieved in these last years CP-\u03a6OTDR have motivated the use of this technology in diverse applications, such as seismology or civil engineering (monitoring of pipelines, train rails, etc.). Besides, new areas of application of this distributed sensor have been explored, based on distributed chemical (refractive index) and temperature-based transducer sensors. In this review, the principle of operation of CP-\u03a6OTDR is revisited, highlighting the particular performance characteristics of the technique and offering a comparison with alternative distributed sensing methods (with focus on coherent-detection-based \u03a6OTDR). The sensor is also characterized for operation in up to 100 km with a low cost-setup, showing performances close to the attainable limits for a given set of signal parameters [\u2248tens-hundreds of pe\/sqrt(Hz)]. The areas of application of this sensing technology employed so far are briefly outlined in order to frame the technology.<\/jats:p>","DOI":"10.3390\/s19204368","type":"journal-article","created":{"date-parts":[[2019,10,11]],"date-time":"2019-10-11T03:07:11Z","timestamp":1570763231000},"page":"4368","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":121,"title":["Distributed Acoustic Sensing Using Chirped-Pulse Phase-Sensitive OTDR Technology"],"prefix":"10.3390","volume":"19","author":[{"given":"Mar\u00eda","family":"R. Fern\u00e1ndez-Ruiz","sequence":"first","affiliation":[{"name":"Department of Electronics, University of Alcal\u00e1, Alcal\u00e1 de Henares, 28805 Madrid, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5254-0605","authenticated-orcid":false,"given":"Luis","family":"Costa","sequence":"additional","affiliation":[{"name":"Department of Electronics, University of Alcal\u00e1, Alcal\u00e1 de Henares, 28805 Madrid, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hugo","family":"F. Martins","sequence":"additional","affiliation":[{"name":"Instituto de \u00d3ptica, CSIC, 28006 Madrid, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2019,10,9]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"569","DOI":"10.1049\/el:19850402","article-title":"Distributed optical fibre Raman temperature sensor using a semiconductor light source and detector","volume":"21","author":"Dakin","year":"1985","journal-title":"Electron. Lett."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"1903","DOI":"10.1364\/OL.42.001903","article-title":"Resolving 1 million sensing points in an optimized differential time-domain Brillouin sensor","volume":"42","author":"Soto","year":"2017","journal-title":"Opt. 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