Distributed optical strain sensing measurements down to cryogenic temperatures.

Rayleigh backscattering (RBS)-based distributed fiber sensors technology is becoming more and more crucial in various fields such as aerospace and defense, automotive, civil, and geotechnical. This technology is measuring the naturally occurring Rayleigh backscatter level in the optical fiber core; thus, any standard single-mode telecom optical fiber can be used. The application of distributed optical fiber strain sensing in the harsh environments of the European Organization for Nuclear Research required several mechanical tests to study the accuracy of strain sensing in cryogenic conditions. This study compares the performance of a RBS-based distributed optical fiber strain sensing down to cryogenic temperatures (4.2 K) with previously validated instrumentations such as electrical strain gauges and fiber Bragg grating technologies.