Preliminary results of an optical-fiber distributed temperature sensor using neodymium as the active fiber dopant have been reported.1 An Investigation has been made of fibers doped with the rare earths neodymium, erbium, praseodymium, and holmium which were fabricated using the method previously reported.2 Silica fiber doped with holmium has an order of magnitude greater temperature sensitivity than the other rare earths. The sensitivity of the absorption to temperature is thought to be due to a satellite band on the long-wavelength side of the main absorption bands, as shown in the attenuation plots in Fig. 1. Thermal population at this energy level causes the attenuation to increase rapidly with temperature.
© 1987 Optical Society of AmericaPDF Article