Electrical - Electronic Engineering / Elektrik - Elektronik Mühendisliği

Permanent URI for this collectionhttps://hdl.handle.net/11147/11

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Author: search.filters.author.Megret, Patrice

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  • Article
    Citation - WoS: 24
    Citation - Scopus: 26
    Fiber Bragg Grating Regeneration at 450°c for Improved High Temperature Sensing
    (The Optical Society, 2019) Chah, Karima; Yüksel, Kıvılcım; Kinet, Damien; Yazd, Nazila Safari; Megret, Patrice; Caucheteur, Christophe
    Type-I fiber Bragg gratings photo-inscribed in hydrogen-loaded B/Ge co-doped silica single-mode optical fibers have been regenerated efficiently at 450 degrees C, which is the lowest temperature reported so far. The mechanical strength of the annealed fiber is preserved while ensuring temperature sensing of the regenerated gratings up to 900 degrees C. Unlike low temperature cycles (<= 600 degrees C), an annealing process at higher temperatures revealed faster regeneration for strong gratings. Changes in grating strength were also measured before the regeneration cycle. These behaviors suggest the contribution of different mechanisms to the regeneration process with different relative dynamics. (C) 2019 Optical Society of America.
  • Article
    Citation - WoS: 9
    Citation - Scopus: 13
    Effect 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, Marc
    Plasma 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.