In this work, we report on a simple, but highly sensitive sensor based on two intrinsic Fabry-Pérot interferometers (FPI) inscribed in a standard optical fiber. A brief theoretical study on the Vernier effect is presented, followed by a simulation of the FPIs physical characteristics to achieve the desired sensitivity enhanced factor. Based on the simulation results, the FPIs were fabricated using a custom micromachining setup based on a near-infrared femtosecond laser and a motorized XYZ platform. A real-time monitoring was performed throughout the entire process, by visualizing the inscription with a CCD camera and recording the resulted spectra. High-resolution was demonstrated for the manufactured devices, achieving, in the best-case, values of ~7 nε and 0.001°C for strain and temperature, respectively. The sensor’s performance allied with its versatile and customizable configuration allows an operando and in-situ strain and temperature monitoring under harsh environments.

Date Published: 28 August 2019
PDF: 4 pages
Proc. SPIE 11199, Seventh European Workshop on Optical Fibre Sensors, 111992U (28 August 2019); doi: 10.1117/12.2539964

Published in SPIE Proceedings Vol. 11199:
Seventh European Workshop on Optical Fibre Sensors
Kyriacos Kalli; Sinead O. O'Keeffe; Gilberto Brambilla, Editor(s)