Optoelectronic device for distributed measurement by means of optical fibre

An optoelectronic distributed measuring device based on optical fiber, said device comprising a continuous light source emitting a continuous light signal at a first frequency ν0, a modulator capable of imposing a frequency shift νA of at least 100 Mhz on the continuous signal and transforming it into a pulse signal to be injected into an optical fiber to be tested, and a photodetector capable of detecting a backscattering signal from the optical fiber to be tested, resulting from a spontaneous Brillouin backscattering and/or a Rayleigh backscattering from said optical fiber to be tested,

• a first coupler and a second coupler, said first coupler being capable of dividing said continuous light signal into two signals of identical frequency distributed into a first arm and a second arm,
• said first arm connecting the first coupler to a reference fiber block including a reference fiber, said reference fiber block being capable of emitting another light signal with a frequency ν0−νbref, where νbref is the Brillouin frequency of the reference fiber without deformation and at a reference temperature,
• said second arm connecting the first coupler to the second coupler located upstream of the photodetector and capable of transmitting to the second coupler a continuous light signal at a frequency ν0, thus constituting a local oscillator, said second coupler being capable of coupling the signal of the local oscillator to the backscattering signal from said optical fiber to be tested before transmitting it to the photodetector,
• the backscattering signal being modulated at a frequency νrB equal to ν0−νbref+νA+νbAS, where νbAS is the anti-Stokes Brillouin backscattering frequency measurable at any point z of said optical fiber where νA is the natural frequency of the modulator, and
• said photodetector being capable of transmitting the received backscattering signal to a processor capable of linking modulation of the backscattering signal to a temperature value and a deformation value at any point z of said optical fiber (15) to be tested.