OPTICAL PULSE REFLECTOMETRY DEVICE AND METHOD Russian patent published in 2008 - IPC H04B10/08 G01M11/00 

FIELD: physics.

SUBSTANCE: said utility invention relates to optical fibre sensors based on optical pulse reflectometry, namely, the measurement of the reflection factor, at which a pulse or pulse series are introduced in the optical fibre and the signal returns to the input end and is formed by the reflected and diffused light in the fibre. The method of optical pulse reflectometry of the parameter perception contains the following stages: application of the optical power at the probe wavelength to the optical fibre and generation of output electric signals in response to the back scattered optical radiation from the optical fibre. In one of the aspects of the invention, the optical fibre contains the first and second fibre sections, the second section having lower non-linear effect occurrence intensity threshold than the first fibre section and is located in the area being tested. The optical radiation at the probe wavelength is introduced in the said first fibre section, with intensity lower than the non-linear effect occurrence intensity threshold of the first fibre section but higher than the non-linear effect occurrence intensity threshold of the second fibre section. The attenuation properties of the said first fibre section are selected so that the intensity of the optical radiation at the probe wavelength reaching the second section are lower than the non-linear effect occurrence intensity threshold of the said second fibre section. In the other aspect of the invention, the optical fibre contains the first and second sections connected by a remote amplifier, the amplifier gain being selected so as to compensate for the attenuation at the probe wavelength in the first section.

EFFECT: enhanced signal-to-noise ratio during far end fibre section measurements.

14 cl, 8 dwg