Open AccessCorrelation technique using of-the-shelf CW DFB laser for interrogation of fiber optic sensors
Author(s) -
Mikhail G. Shlyagin,
Luis Alfredo Giraldo Arias,
Jorge Rivera
Publication year - 2021
Publication title -
suplemento de la revista mexicana de física
Language(s) - English
Resource type - Journals
ISSN - 2683-2585
DOI - 10.31349/suplrevmexfis.2.1.87
Subject(s) - reflectometry , optics , optical time domain reflectometer , fiber optic sensor , interferometry , signal (programming language) , optical fiber , materials science , fiber bragg grating , laser , polarization maintaining optical fiber , optoelectronics , physics , time domain , computer science , computer vision , programming language
The paper presents a simple fiber-optic sensor technique based on methods of correlation optical time domain reflectometry. A correlation reflectometry technique can measure distribution of reflection coefficient along the optical fiber by calculating the correlation function between a probe optical signal (reference) and the signal returned back due to reflections or/and back-scattering from the fiber under the test. To obtain the best sensor performance, the probe signal power should be a truly random function of time. As an optical source we use a free-running DFB laser diode operating in a continuous wave regime without any external modulation. To generate the probe test signal, laser light is passed through an interferometer with an optical path difference much longer than the coherence length of the laser light. The light intensity at the interferometer output has a truly random fluctuations and its auto correlation function is suitable for correlation optical reflectometry. We present results of experimental verification of the techniques in different sensor configurations. Multipoint sensor using very low reflective fiber Bragg gratings with reflectivity of 0.01% printed in a long SMF-28 optical fiber was demonstrated.