FIELD: measuring equipment.
SUBSTANCE: invention relates to fiber measuring equipment, to fiber-optic security detectors. An optical circuit of the fiber-optic security detector, which uses a closed interferometer with two arms, is a closed interferometer for the detector, implementing an optical circuit containing a closed circuit forming a reflection signal, in which the same segments of cable optical fiber are sensitive elements of the interferometer, in which a phase shift of a probing pulse is created in accordance with the applied physical impact, wherein the closed circuit is a Mach-Zehnder interferometer. In this case, the length of one of arms is compensated with an optical delay line, wherein the optical delay line is an optical delay line made by means of connection into an optical circuit of reserve cores of the fiber-optic cable, or an optical delay line made in the form of a coil of optical fiber.
EFFECT: provision of uniform sensitivity of a sensitive part of a detector; increase in the reliability; simplification of mounting, as well as implementation by the invention of its purpose.
5 cl, 12 dwg
