eprintid: 1514415 rev_number: 29 eprint_status: archive userid: 608 dir: disk0/01/51/44/15 datestamp: 2016-12-02 12:59:29 lastmod: 2021-09-23 22:41:37 status_changed: 2016-12-02 12:59:29 type: article metadata_visibility: show creators_name: Martins, HF creators_name: Shi, K creators_name: Thomsen, BC creators_name: Martin-Lopez, S creators_name: Gonzalez-Herraez, M creators_name: Savory, SJ title: Real time dynamic strain monitoring of optical links using the backreflection of live PSK data ispublished: pub divisions: UCL divisions: B04 divisions: C05 divisions: F46 note: Published by The Optical Society under the terms of the Creative Commons Attribution 4.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. abstract: © 2016, OSA - The Optical Society. All rights reserved.A major cause of faults in optical communication links is related to unintentional third party intrusions (normally related to civil/agricultural works) causing fiber breaks or cable damage. These intrusions could be anticipated and avoided by monitoring the dynamic strain recorded along the cable. In this work, a novel technique is proposed to implement real-time distributed strain sensing in parallel with an operating optical communication channel. The technique relies on monitoring the Rayleigh backscattered light from optical communication data transmitted using standard modulation formats. The system is treated as a phase-sensitive OTDR (ΦOTDR) using random and non-periodical non-return-to-zero (NRZ) phase-shift keying (PSK) pulse coding. An I/Q detection unit allows for a full (amplitude, phase and polarization) characterization of the backscattered optical signal, thus achieving a fully linear system in terms of ΦOTDR trace coding/decoding. The technique can be used with different modulation formats, and operation using 4 Gbaud single-polarization dual PSK and 4 Gbaud dual-polarization quadrature PSK is demonstrated. As a proof of concept, distributed sensing of dynamic strain with a sampling of 125 kHz and a spatial resolution of 2.5 cm (set by the bit size) over 500 m is demonstrated for applied sinusoidal strain signals of 500 Hz. The limitations and possibilities for improvement of the technique are also discussed. date: 2016-09-19 date_type: published official_url: http://doi.org/10.1364/OE.24.022303 oa_status: green full_text_type: pub language: eng primo: open primo_central: open_green article_type_text: Journal Article verified: verified_manual elements_id: 1156482 doi: 10.1364/OE.24.022303 lyricists_name: Shi, Kai lyricists_name: Thomsen, Benn lyricists_id: KSHIX95 lyricists_id: BTHOM60 actors_name: Shi, Kai actors_id: KSHIX95 actors_role: owner full_text_status: public publication: Optics Express volume: 24 number: 19 pagerange: 22303-22318 issn: 1094-4087 citation: Martins, HF; Shi, K; Thomsen, BC; Martin-Lopez, S; Gonzalez-Herraez, M; Savory, SJ; (2016) Real time dynamic strain monitoring of optical links using the backreflection of live PSK data. Optics Express , 24 (19) pp. 22303-22318. 10.1364/OE.24.022303 <https://doi.org/10.1364/OE.24.022303>. Green open access document_url: https://discovery.ucl.ac.uk/id/eprint/1514415/1/shi_oe-24-19-22303.pdf