Optical temperature probe employing rare earth absorption

Abstract

A temperature probe formed by an optical fiber having a core fabricated from a glass host doped with a trivalent rare earth is positioned at the location temperature is to be measured. One of the rare earth elements, europium, has low lying energy levels that have significant population changes over certain desirable temperature ranges, i.e., related to the population of this particular energy level transition is monitored to determine the temperature at the location of the temperature probe. A simplified embodiment of a temperature measuring device incorporating the optical temperature probe includes at least one LED, or equivalent, to generate light into the input end of the optical fiber. The preselected wavelength of light that corresponds to the absorption line of interest experiences a change in strength as function of temperature. A detector at the output end measures changes in strength of the absorbed light by normalizing to an unabsorbed wavelength of light.

Dependencies are inferred from the claim text.