FIELD: measuring equipment.
SUBSTANCE: invention relates to measuring equipment using optical fibre, namely, to fibre-optic security detectors. The fence with a linear part of a fibre-optic security detector constitutes a fence formed by a non-continuous obstacle stretched between posts installed on foundations. The non-continuous obstacle comprises a sensing element of the detector placed along a curvilinear trajectory providing vibration sensitivity and additional connectivity of the elements of the non-continuous obstacle. Joint interferometers with a station part with a transceiver apparatus connected with the linear part of said detector are included in the detector. The linear part constitutes a branched optical circuit based on splitters and a fibre-optic cable by means of connecting couplings and a transport cable connecting the transceiver apparatus and the sensing elements of the security fibre-optic detector, wherein said circuit comprises a closed and open contours forming reflection signals wherein the same segments of the optical fibre of the cable are the sensing elements of interferometers wherein a phase shift of the probing pulse is created in accordance with the exerted physical impact, the same for both contours. The closed contour constitutes a Sagnac interferometer, and the open contour constitutes a Michelson interferometer.
EFFECT: increase in the accuracy of determining the site of impact on the sensing element, provided uniform sensitivity of the sensing part of the detector, increase in the reliability of the detector, facilitated installation.
10 cl, 12 dwg
