FIELD: physics.
SUBSTANCE: invention relates to measuring equipment using optical fibre, namely to security fibre-optic detectors, as well as to products, methods and means related to security fibre-optic detectors and their aspects. Disclosed fibre-optic security detector, in which combined interferometers are used, comprises a station part with a transceiving device connected to the linear part of the said detector, wherein the linear part is a branched optical circuit based on splitters and a fibre-optic cable, which by means of couplings and a transport cable connect the transceiving device and the sensitive elements of the security fibre-optic detector, containing closed and open circuits, which form reflection signals, in which the same sections of optical fibre of the cable are sensitive elements of interferometers, in which a phase shift of the probing pulse is created, in accordance with the physical effect, which is the same for both circuits. Closed circuit is a Mach-Zehnder interferometer, and the open circuit is a Michelson interferometer.
EFFECT: providing uniform sensitivity of the sensitive part of the security fibre-optic detector; high reliability of the security fibre-optic detector, in particular, by receiving two signals from the same probing pulse, which provides greater protection of the protected perimeter from the effect of interference factors, the effect of the measurement properties of the transceiving device; simplification of installation due to elimination of necessity to use compensation coils in its composition, which are necessary for compensation of length of fibres of the sensitive element, as well as implementation of its purpose.
10 cl, 12 dwg
