Research papers - Sensors 2009, 9(10), 8377-8381
Arrays of Regenerated Fiber Bragg Gratings in Non-Hydrogen-Loaded Photosensitive Fibers for High-Temperature Sensor Networks
Eric Lindner, Christoph Chojetztki, Sven Brueckner, Martin Becker, Manfred Rothhardt, Johan Vlekken, Hartmut Bartelt
Short description
Fiber Bragg gratings are well established as strain and temperature sensors, not only in the field of structural health monitoring in civil engineering but also in the aerospace and medical industries. The advantages of fiber Bragg gratings are their compact size and the possibility of multiplexed sensors, even over long distances. For use as a temperature sensor, the induced refractive index modification is crucial. Recently, a new type of refractive index modification was introduced by Canning et al. [1,2], which leads to a regeneration of fiber Bragg gratings at temperatures of about 900 °C. This regenerative process was observed in germanium-boron-doped photosensitive fibers but only by applying hydrogen loading. We recently reported a similar process in germanium doped fibers but without any hydrogen loading and by using the 248 nm wavelength for grating inscription [3]. The regeneration process, carried out at lower temperatures and leads to temperature stabilities of up to 600 °C. By using an interferometric grating writing technique we can generate arrays of regenerated fiber Bragg gratings for high-temperature sensor networks. The concept of such array sensor structures is discussed in this paper.