From Event: SPIE Optics + Optoelectronics, 2019
The design and performance evaluation of an innovative, small size, compactly packaged high temperature interferometric optical sensor for harsh environments is reported. The sensor was built with a short segment of strongly coupled multi-core optical fiber (MCF) spliced to a typical single mode fiber (SMF). Matlab MathWorks and PhotonDesign simulation programs were used to design the sensor to monitor the widest temperature range possible with a commercial sensor interrogator. The SMF-MCF structure was protected by two temperature-resistant tubes: an inner ceramic tube with an internal hole that matched the MCF diameter in order keep it tightly in axial direction to avoid the effects of bending and/or vibrations that could be misinterpreted as temperature measurements, and an outer metallic tube to provide protection against impacts. The calibration of our packaged MCF sensor was carried out in a high temperature furnace at the facilities of the Aeronautical Technologies Center (CTA) and a calibrated standard K-type thermocouple was used as a reference. The calibration was performed repeatedly in the range from 200 to 950 °C and the gathered spectra were processed entirely by a custom program made in Matlab MathWorks. Our sensor responded lineally in the tested range with an average temperature sensitivity of 29.1 pm/°C and showed high robustness against vibrations. Results indicate that our MCF sensor is as accurate as the K-type thermocouple with the advantage of its appropriate passiveness for harsh environmental industrial applications.
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Josu Amorebieta, Gaizka Durana, Angel Ortega-Gomez, Rubén Fernández, Javier Velasco, Idurre Sáez de Ocáriz, Joseba Zubia, Enrique Antonio-Lopez, Axel Schülzgen, Rodrigo Amezcua-Correa, and Joel Villatoro, "Strongly coupled multi-core fiber-based interferometer for high temperature sensing," Proc. SPIE 11029, Micro-structured and Specialty Optical Fibres VI, 110290R (Presented at SPIE Optics + Optoelectronics: April 04, 2019; Published: 15 April 2019); https://doi.org/10.1117/12.2520711.