INTERFEROMETRIC FIBEROPTIC HYDROGEN SENSOR

A hydrogen sensor has been developed in which the sensing element is a palladium wire, mechanically attached to a monomode optical fiber. In the presence of hydrogen, the palladium is converted to palladium hydride, with consequent changes in the physical dimensions of the wire. In turn, these dimensional changes produce a longitudinal strain in the optical fiber. The strain is transduced to a phase retardance in a light beam guided by the fiber, and which is recovered interferometrically. The sensor has been demonstrated in a nitrogen atmosphere at laboratory temperature.