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Proceedings Paper

All-fiber micro-machined Fabry-Perot strain sensor
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Paper Abstract

This paper presents the design, fabrication process, and experimental evaluation of a high-sensitivity, all-silica, all-fiber, micro machined Fabry-Perot strain-sensor. This sensor has a short Fabry-Perot cavity and thus allows for the application of low-resolution spectral interrogation systems; in our case the commercial white light signal interrogator was used. The fabrication process includes the design and production of special sensor-forming optical-fiber. This fiber includes a central titanium-doped region, a phosphorus doped-ring surrounding a titanium doped region, and pure silica cladding in order to produce the proposed sensor, two sections of sensor forming fiber are cleaved and etched in a HF/IPA solution. The phosphorus-doped region etches at a considerably higher rate than the other fiber-sections, and thus creates a deep gutter on the cleaved fibers frontal surface. The titanium-doped region etches at a rate that is, to some extent, higher than the etching-rate of pure silica, and thus creates a slightly retracted surface relative to the pure silica fiber-cladding. The etched fibers are then re-spliced to create an all-silica strain sensor in "double configuration", which has a section of etched sensor-forming fiber on both sides. Thus this sensor has a long active length, whilst the length of the Fabry-Perot cavity can be adjusted by a titanium-doping level. The central titanium-doped region also creates a waveguide structure that is used to deliver light to the cavity through one of the fibers. The proposed fabrication process is cost-effective and suitable for high-volume production. The greatest achievement of the depicted in-line strain sensor is the extension of its active sensor length, which is more than 50 times greater than the sensor-cavity's length, and is thus approximately 50 times more sensitive to strain. This sensor also exhibits low-intrinsic temperature sensitivity.

Paper Details

Date Published: 25 April 2012
PDF: 8 pages
Proc. SPIE 8426, Microstructured and Specialty Optical Fibres, 84261D (25 April 2012); doi: 10.1117/12.921845
Show Author Affiliations
Simon Pevec, Univ. of Maribor (Slovenia)
Denis Đonlagić, Univ. of Maribor (Slovenia)

Published in SPIE Proceedings Vol. 8426:
Microstructured and Specialty Optical Fibres
Kyriacos Kalli; Alexis Mendez, Editor(s)

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