FIBRE-OPTIC DEVICE OF LONG LENGTH WITH LOW-POWER SOURCE FOR DETECTING VIBRATION ACTION Russian patent published in 2016 - IPC G01H9/00 

FIELD: computer engineering.

SUBSTANCE: invention relates to fibre-optic sensor systems used in systems for monitoring of extended and large-size objects and can be used for monitoring state of vessel and elements of its design (tanks, etc.) by acoustic emission diagnosis, detecting acoustic signals from these elements, which act on optical fibre and can be registered by means of coherent reflectometry method. Technical result is achieved by fact that fibre-optic device of large length with a radiation source of low power for detecting vibration action acoustic frequency range includes first chain of measuring channel of narrow-band coherent low-power radiation source (laser with long coherence length) 1, optical insulator 2, coupler 3, controlled by acoustic-optical modulator 4 driver, optical circulator 6 and fibre-optic sensor section 7. For scattered signal from the sensor section 7 through first circulator 6, there is second serial circuit from preamplifier 8, optical filter 9, second circulator 10, narrow-band Fabry-Perot filter 11, third circulator 12 and first digital photo receiver 13. From second output of splitter 3 in calibration channel with second splitter 16 for dividing undistorted portion of radiation source 1 into the second digital photodetector 17 and delivery of second part of that initial continuous radiation signal through third circulator 12, then through Fabry-Perot filter 11 and second circulator 10 into third digital photo receiver 18. Outputs of all three digital photodetectors are connected to digital computing unit 14, from which feedback signal generated in unit 14 is supplied to tuning input of Fabry-Perot filter 11 via feedback unit 15. Output of computer unit 14 for displaying results of inspecting (registration of vibration effect on sensory fibre-optic section) is connected to display unit 19.

EFFECT: problem is increasing of dynamic range of useful signal measurements of acoustic vibrations of frequency range and longer length of sensor section along inspected object.

1 cl, 2 dwg