Patent ID: 7874725

Claim:
An optical fiber temperature distribution measuring apparatus, comprising: a light source for inputting a pulse light to an optical fiber to be measured; a signal detecting unit for detecting a received light intensity of a predetermined light included in a backscattering light generated by an input of the pulse light in the optical fiber in a hydrogen atmosphere and in an atmosphere without hydrogen, the predetermined light comprising any of a combination of a Stokes light and an anti-Stokes light, a combination of the Stokes light, the anti-Stokes light, and a Rayleigh light, and a combination of the Rayleigh light and the anti-Stokes light; and a signal processing unit for calculating a value corresponding to a variation of a received light intensity due to a hydrogen molecular absorption in the optical fiber based on the received light intensity of the predetermined light, calculating a ratio of a value corresponding to a variation of a received light intensity of the anti-Stokes light with respect to the value corresponding to the variation of a received light intensity of a light other than the anti-Stokes light in the predetermined light, to provide a predetermined coefficient, and calculating a variation of the received light intensity due to the hydrogen molecular absorption of the anti-Stokes light by the predetermined coefficient, when a temperature of the optical fiber is measured, thereby calibrating the received light intensity of the anti-Stokes light to remove an influence of the hydrogen molecular absorption from the received light intensity of the anti-Stokes light.