Electrical - Electronic Engineering / Elektrik - Elektronik Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/11
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Article Citation - WoS: 7Citation - Scopus: 10Analysis of Crosstalk Effects in Phase-Otdr System Using Fiber Bragg Grating Array(Elsevier, 2023) Koçal, Ertunga Burak; Yüksel, Kıvılcım; Wuilpart, MarcIn this paper, the parasitic components (i.e., multi-reflections, Rayleigh scattering, photodetector noise, and phase variations due to external perturbations) are analysed and based on this analysis, a new signal to noise ratio (SNR) definition is provided suitable for the FBG-assisted Phase-OTDR system. A detailed analysis of performance parameters in the presence of multi reflection crosstalk (including its first- and second-order components) and spectral shadowing crosstalk is presented. SNR was calculated for different reflectivity and spacing lengths showing that the maximum number of cascaded FBGs can be significantly increased by using lower FBG reflectivity. It was also observed that the spacing length distance does not have a significant impact on the maximum number of FBGs that can be interrogated. By comparing single-pulse and double-pulse configurations, the use of double pulse was shown to provide higher SNR values when the number of FBGs is around 100 FBGs. The multi-reflection crosstalk when combined with the spectral-shadowing effect was demonstrated to create secondary crosstalk components making the interpretation of spectral analysis more difficult.Article Citation - WoS: 3Citation - Scopus: 3Current Sensing Using a Phase-Sensitive Optical Time Domain Reflectometer: Feasibility Study(Elsevier, 2022) Wuilpart, Marc; Şirin, Şamil; Yüksel Aldoğan, KıvılcımA novel method for distributed current sensing using an FBG-assisted Phase-OTDR with Mach-Zehnder Interferometer is proposed. The detrimental effect of the intrinsic linear birefringence of the sensing fiber is solved by calibration. An FBG pair is written at the two ends of the spun fiber coil to eliminate phase fading and increase the measurement accuracy. A simulation tool was developed to reveal the feasibility of the approach by investigating the impact of the detector noise as well as the effects of bending- and FBG-induced linear birefringence on the sensing performance.Article Citation - WoS: 101Citation - Scopus: 129Scientific Applications of Distributed Acoustic Sensing: State-Of Review and Perspective(MDPI, 2022) Gorshkov, Boris G.; Yüksel, Kıvılcım; Fotiadi, Andrei A.; Wuilpart, Marc; Korobko, Dmitry A.; Zhirnov, Andrey A.; Lobach, Ivan A.This work presents a detailed review of the development of distributed acoustic sensors (DAS) and their newest scientific applications. It covers most areas of human activities, such as the engineering, material, and humanitarian sciences, geophysics, culture, biology, and applied mechanics. It also provides the theoretical basis for most well-known DAS techniques and unveils the features that characterize each particular group of applications. After providing a summary of research achievements, the paper develops an initial perspective of the future work and determines the most promising DAS technologies that should be improved.Conference Object Citation - WoS: 14Citation - Scopus: 14An Overview of the Recent Advances in Fbg-Assisted Phase-Sensitive Otdr Technique and Its Applications(IEEE, 2020) Yüksel, Kıvılcım; Koçal, Ertunga Burak; Jason, Johan; Wuilpart, Marc; Sainz, Manuel Lopez-AmoIn this paper, we discuss the operation principles, sensing mechanism, challenges and application areas of FBG-assisted phase-sensitive optical time-domain reflectometry. A special emphasis is given to the interrogation of fiber Bragg grating arrays for vibration sensing application. Results obtained by different research groups are compared in terms of performance characteristics and future perspectives. Recent progress obtained through our research collaboration are also presented. In particular, the detrimental spectral shadowing effect and multiple reflection crosstalk are analysed and mitigation techniques are proposed. © 2020 IEEE.Article Citation - WoS: 19Citation - Scopus: 21Spectral Shadowing Suppression Technique in Phase-Otdr Sensing Based on Weak Fiber Bragg Grating Array(The Optical Society, 2019) de Miguel Soto, Veronica; Jason, Johan; Kurtoğlu, Deniz; Lopez-Amo, Manuel; Wuilpart, MarcA postprocessing procedure is presented to suppress spectral shadowing in phase-OTDR sensing systems based on a weak fiber Bragg grating array. A complete theoretical analysis of the interfering signals has been carried out to identify a compensation method. The proposed approach has been applied to simulated and experimental phase-OTDR in the context of vibration measurements. Fast Fourier transform has been employed to analyze the obtained results, which has verified the validity of the proposed method to suppress spectral shadowing. (C) 2019 Optical Society of AmericaArticle Citation - WoS: 9Citation - Scopus: 13Effect of Faraday Mirror Imperfections in a Fiber Optic Current Sensor Dedicated To Iter(Elsevier Ltd., 2019) Karabulut, Doğuş; Miazin, Anton; Gusarov, Andrei; Moreau, Philippe; Leysen, Willem; Megret, Patrice; Wuilpart, MarcPlasma current measurements in ITER are safety-related and must therefore satisfy a very demanding specification. In this paper, the use of the Fiber Optics Current Sensor (FOCS) operating in the reflection mode with a Faraday mirror to perform plasma current measurements is analyzed. Based on the Jones matrix formalism, we performed numerical simulations to investigate the impact of the Faraday mirror detuning on the measurement accuracy. We show that the use of standard commercial components does not allow to satisfy the ITER requirements for the whole plasma current range. A simple solution to the problem is proposed, which consists in taking into account a mirror calibration in the current estimator. We show that the achievable mirror calibration accuracy is sufficient to fulfill the ITER requirements.Article Development of a Phase-Otdr Interrogator Based on Coherent Detection Scheme(Uludağ Üniversitesi, 2018) Yüksel, Kıvılcım; Jason, Johan; Wuilpart, MarcWe present in this work, the experimental demonstration of a phase-sensitive Optical Time- Domain Reflectometer (phase-OTDR) having coherent detection scheme. An analysis algorithm has also been developed to calculate amplitude and phase evolution of the experimental phase-OTDR traces. The efficiency of the analysis algorithm to determine the position of the applied vibration has been verified for a single and two simultaneous vibrations. The slow-time analysis results show a good agreement with the mathematical calculations discussed in the paper. This work could have a technological implication in many fields such as distributed vibration sensor for railway monitoring applications.Conference Object Laboratory Evaluation of a Phase-Otdr Setup for Railway Monitoring Applications(Institute of Electrical and Electronics Engineers Inc., 2017) Jason, J.; Yüksel, Kıvılcım; Wuilpart, MarcPhase-sensitive optical time-domain reflectometry (phase-OTDR) has recently drawn increased attention for applications within the railway transportation sector. In this paper we present a laboratory approach to demonstrate the feasibility of an interrogator of vibrations along railways by means of fiber-optic cables. Contrary to the common use of piezo-electric phase modulators in laboratory setups, a vibration shaker is used to excite a plastic tube to which the fiber is attached. Measurement of event position and frequency is demonstrated in a range up to 7000 Hz.Conference Object Citation - WoS: 5Centralised Optical Monitoring of Tree-Structured Passive Optical Networks Using a Raman-Assisted Otdr(Institute of Electrical and Electronics Engineers Inc., 2007) Yüksel, Kıvılcım; Letheux, S.; Grillet, A.; Wuilpart, Marc; Giannone, D.; Hancq, J.; Ravet, G.; Mégret, PatriceMonitoring of tree-structured Passive Optical Networks from a central office is difficult to achieve using a standard OTDR. Switchable reflective elements placed at the ONU can help to discriminate between the branches. In parallel, a Raman assisted OTDR is shown to increase the dynamic range of the reflectometry measurement, thus enabling to detect more faults in the network, and especially fibre breaks after the splitter. ©2007 IEEE.Conference Object Citation - WoS: 30Optical Frequency Domain Reflectometry: a Review(Institute of Electrical and Electronics Engineers Inc., 2009) Yüksel, Kıvılcım; Wuilpart, Marc; Moeyaert, Véronique; Mégret, PatriceIn this paper, we discuss the operation principles, challenges and application areas of optical frequency domain reflectometry technique. A review of OFDR systems is given considering both Incoherent-OFDR and Coherent- OFDR groups. Results obtained by different research groups are compared in terms of performance characteristics, and future perspectives. Recent progresses obtained within our laboratory are also presented. ©2009 IEEE.