Patent ID: 7526149

Claim:
An optical fiber strain-temperature sensing system comprising: a first optical source configured for generating a first light signal having a first wavelength; a second optical source configured for generating a second light signal having a second wavelength different from the first wavelength; a plurality of optical routing elements configured for directing the first and second light signals to an external sensing cable for the respective generation of first and second Brillouin scattered light signals; a first frequency mixer having a first input coupled to the first optical light source; a second frequency mixer having a first input coupled to the second optical light source; the optical routing elements also being configured for directing the first and second Brillouin scattered light signals returning from an external sensing cable respectively to second inputs of the first and second frequency mixers; a first transducer coupled to an output of the first frequency mixer and configured for generating a first electrical signal indicative of a Brillouin frequency shift of the first light signal; a second transducer coupled to an output of the second frequency mixer and configured for generating a second electrical signal indicative of a Brillouin frequency shift of the second light signal; and a processor coupled to the first and second transducers, the processor being configured for determining the strain and temperature characteristics of an external sensing cable based on the Brillouin frequency shifts of the first and second light signals.