Femtosecond laser induced fiber Bragg gratings for harsh environment sensing applications

Abstract

Fiber Bragg grating sensors have been developed beyond a laboratory curiosity to become a mainstream sensing technology because of their small size, passive nature, immunity to electromagnetic interference, and capability to simultaneously measure multiple physical parameters such as temperature, strain and pressure. Recently, high temperature stable gratings based on regeneration techniques and femtosecond infrared laser processing have shown promise for use in extreme environments such as high temperature, pressure or ionizing radiation. Such gratings are ideally suited for energy production applications where there is a requirement for advanced energy system instrumentation and controls that are operable in harsh environments. This presentation will give a review of some of the more recent developments of femtosecond laser induced fiber Bragg gratings.

Negative axial strain sensitivity in gold-coated eccentric fiber Bragg gratings

“…Nevertheless, gratings that can be used in harsh environment with reliable self-compensation sensing solutions are still relevant to produce, especially for structural health monitoring, nuclear and oil & gas industries1314. As FBGs in standard optical fibers are sensitive to both strain and temperature, different techniques have been set-up to discriminate between these two measurands.…”