Patent ID: 8333505

Claim:
A method for extending the distance range of a fiber optic distributed temperature system using a single optical source comprising the steps of: a. transmitting, in a first time period, a first optical signal, at a first energy level and at a first wavelength through an optical fiber; b. collecting backscatter Raman Stokes and anti-Stokes signals as a result of said first transmission of said optical signal from a first length of the optical fiber; c. transmitting, in at least one additional time period, an additional optical signal at higher energy level and at the first wavelength through said optical fiber; d. collecting backscatter Raman Stokes and anti-Stokes signals as a result of said additional transmission from an additional length of the optical fiber; wherein said backscatter Raman Stokes and anti-Stokes signals are those resulting from the spontaneous scattering of the additional optical signal at the first wavelength; e. using the collected Raman Stokes and anti-Stokes backscatter as a result of said first transmission to calculate a temperature profile of said first length of optical fiber and the collected Raman Stokes and anti-Stokes backscatter as a result of said additional transmissions to calculate a temperature profile of said additional length of optical fiber, and adding the temperature profiles to display a temperature response of the whole sensing fiber.