Noise analysis of coherent and non-coherent detection in Φ-OTDR systems with chirped pulses
Authors
Vidal Moreno, Pedro Jose; Becerril, Carlos Ernesto; Fernández Ruiz, María Del Rosario; Fidalgo Martins, Hugo; Martín López, Sonia; [et al.]Publisher
SPIE
Date
2023-05-23Funders
Ministerio de Ciencia e innovación
Comunidad de Madrid
Agencia Estatal de Investigación
European Commission
Bibliographic citation
Pedro J. Vidal-Moreno, Carlos Becerril, Maria R. Fernández-Ruiz, Hugo Martins, Sonia Martin-Lopez, and Miguel Gonzalez-Herraez "Noise analysis of coherent and non-coherent detection in Φ-OTDR systems with chirped pulses", Proc. SPIE 12643, European Workshop on Optical Fibre Sensors (EWOFS 2023), 126432K.
Keywords
Fiber Optics Sensors
DAS
Rayleigh Scattering
ΦOTDR
Coherent Detection
Optical Filter
SNR
Description / Notes
European Workshop on Optical Fibre Sensors (EWOFS 2023), 23/05/2023-26/05/2023, Mons, Bélgica.
Project
info:eu-repo/grantAgreement/MICINN//RYC2021-032167-I
info:eu-repo/grantAgreement/MICINN//RYC2021-035009-I
info:eu-repo/grantAgreement/CAM//S2018%2FNMT4326/ES/SENSORES E INSTRUMENTACION EN TECNOLOGIAS FOTONICAS2/SINFOTON2
info:eu-repo/grantAgreement/MICINN//PLEC2021-007875/ES/SISTEMA DE MONITORIZACION PARA LA PROTECCION Y MANTENIMIENTO PREDICTIVO DE INFRAESTRUCTURAS DE CABLE SUBMARINO/PSI
info:eu-repo/grantAgreement/AEI/Plan Estatal de Investigación Científica, Técnica y de Innovación 2021-2023/CPP2021-008869/ES/TECNOLOGIAS FOTONICAS MAS RENTABLES PARA LA MONITORIZACION REMOTA DE LA SISMICIDAD EN ALMACENES GEOLOGICOS DE ZONAS MARINAS PARA LA TRANSICION ENERGETICA/TREMORS
info:eu-repo/grantAgreement/MICINN/Plan Estatal de Investigación Científica, Técnica y de Innovación 2021-2023/PID2021-128000OB-C21
info:eu-repo/grantAgreement/MICINN/Plan Estatal de Investigación Científica, Técnica y de Innovación 2021-2023/PID2021-128000OB-C22
info:eu-repo/grantAgreement/EC/HE/101098992/EU/Tsunami early warning System using Availableseafloor Fiber cablEs/SAFE
Document type
info:eu-repo/semantics/conferenceObject
Version
info:eu-repo/semantics/acceptedVersion
Publisher's version
https://doi.org/10.1117/12.2678310Rights
Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0)
© 2023 SPIE
Access rights
info:eu-repo/semantics/openAccess
Abstract
Chirped-pulse phase sensitive (CP-Φ) OTDR is a distributed sensing technology that allows for quantitative measurement of strain and temperature along an optical fiber by simply direct detection of the Rayleigh backscattering. Typically, chirped pulses have a linear frequency modulation covering few GHz. Backscattered traces must be amplified before detection, which introduces noise and limits the signal-to-noise ratio (SNR) and, therefore, the maximum measurable range. To increase the SNR, an optical filter is usually placed before photodetection aimed at reducing broadband optical noise caused by amplified spontaneous emission. However, narrow-band filters (e.g., 10 GHz bandwidth) are not easily compatible with multi-wavelength approaches, used to improve the long-term stability. Furthermore, in practice it is not straightforward to find narrowband optical filters that continuously match the central frequency of the laser, considering laser wavelength drifts. In this study, the influence of the optical filter bandwidth on the range in CP-ΦOTDR is theoretically investigated for two types of photodetection: direct and coherent. The results show that when using coherent detection, the SNR does not depend on the filter bandwidth. Therefore, it is possible to achieve an equivalent measurement range by using a wide optical filter (e.g., 100 GHz) as compared to that obtained when using direct detection with a narrowband filter. This finding suggests that coherent detection can be used to increase the range in CP-ΦOTDR and could be compatible with the use of multi-wavelength techniques to improve the long-term stability for applications such as civil engineering and seismology.
Files in this item
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Noise_Vidal_EWOFS_2023.pdf | 829.4Kb |
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Noise_Vidal_EWOFS_2023.pdf | 829.4Kb |
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