DOI: 10.22184/1993-7296.FRos.2025.19.6.486.499

The efficiency of functioning and neutralization of speech information leakage channels through the fiber-­optic utilities is largely determined by the noise pollution of the optical channel in the structured cabling systems of the facility. Adaptation of the well-known noise control methods in the fiber-­optic speech information leakage channels allows to significantly increase the signal-to-noise ratio and, consequently, the interception efficiency. In particular, the fiber-­optic subsystem of structured cabling systems at the facility with the distributed measuring properties can be represented as a phased acoustic fiber-­optic array. While using the integration method for multichannel measurement, an informative signal can be isolated against the noise background. Another noise control method represents the comparison of two optical channels with asymmetric acoustic sensitivity (the differential method) that is possible due to the placement of optic fiber duplex cables in the cable ducts. The differential noise reduction method was tested on an experimental unit for investigating the speech information leakage channel that demonstrated a significant increase in the signal-to-noise ratio even at the short cable lengths. The differential method implementation is possible due to the correlation of low-frequency noise in the optical channel over a long period of time (0.1 ms) and a significant light path in the optical fiber (20 km). The given theoretical and practical studies show a high level of danger of acoustic fiber-­optic speech information leakage channels and possible countermeasures.