Abstract: An apparatus for measuring a temperature distribution along an optical fiber, comprises a light source for inputting pulsed-light into the optical fiber, an optical filter for receiving backward Raman-scattered light from the optical fiber and extracting anti-Stokes' light and Stokes' light, an optical attenuator for attenuating the intensity of the Stokes' light extracted by the optical filter, first and second signal paths each of which includes a light-receiving element and an analog-to-digital converter, a signal processor for calculating a temperature distribution along the optical fiber on the basis of the first and second signal paths, and an optical switch having a first input port for receiving the anti-Stokes' light, a second input port for receiving the Stokes' light, a first output port, and a second output port, the optical switch transmitting the anti-Stokes' light and the Stokes' light to the first output port and the second output port in a first switching position and transmitting the Stokes'

Abstract: A temperature distribution measuring apparatus, which inputs pulsed-light into an optical fiber, measures backward Raman-scattered light generated in the optical fiber, and calculates a temperature distribution along the optical fiber in accordance with the ratio of the intensity of anti-Stokes' light to the intensity of Stokes' light of the backward Raman-scattered light.