FIELD: measuring equipment.
SUBSTANCE: invention relates to measuring equipment using optical fiber, namely to fiber-optic security detectors, as well as to products, methods, and means related to fiber-optic security detectors and their aspects. An optical circuit of a fiber-optic security detector, which uses combined interferometers, is claimed, which is combined interferometers for the fiber-optic security detector, implementing the optical circuit containing a closed and open loops forming reflection signals, in which the same segments of optical fiber of a cable are sensitive elements of interferometers, in which a phase shift of a probing pulse is created according to the applied physical impact, the same for both loops. At the same time, the closed loop is a Mach-Zehnder interferometer, and the open loop is a Michelson interferometer, while the optical circuit is placed in a connecting coupling.
EFFECT: provision of uniform sensitivity of a sensitive part of a fiber-optic security detector; increase in the reliability of the fiber-optic security detector, in particular, due to the reception of two signals from the same probing pulse, which provides more protection of the guarded perimeter from the impact of interference factors, impact of drift of measuring properties of a transceiver; simplification of mounting due to elimination of the need for use of compensation coils in its composition, necessary for compensation of the length of fibers of a sensitive element, as well as implementation by the invention of its purpose.
6 cl, 12 dwg
