Assessment of Forming Information Leakage Channel from Optical Fiber Possibility by Thermal Exposure

The article is devoted to assessing the possibility of forming an information leakage channel from an optical fiber defect created by thermal exposure. The properties of optical fiber inhomogeneities caused by such exposure have not been practically studied to date, which determines the relevance of research. Taking into account the above, the purpose of the study is to determine the characteristics of optical fiber inhomogeneities caused by thermal exposure. The methods used. The paper calculates the radiation power losses introduced by a defect caused by thermal action at high temperature, as well as the radiation power removed from the defect beyond the optical fiber. During the studies, the characteristics of optical fiber inhomogeneities caused by thermal action were also estimated using reflectograms. The result. The work that local temperature exposure makes it possible to form a defect in an optical fiber that allows part of the optical radiation to be emitted beyond the fiber, i.e. to create a channel for unauthorized data retrieval. The magnitude of the insertion loss of radiation power on the created defect increased with increasing time of thermal exposure to the optical fiber. When the time of thermal exposure to the optical fiber was less than 1 s, it was not possible to form a defect with significant insertion loss of radiation power, and when the time of thermal exposure was more than 10 s, the insertion loss on the defect exceeded 20 dB, at which data transmission of zonal and trunk fiber-optic communication lines ceases. It is shown that with increasing wavelength of optical radiation propagating along the fiber, the loss of radiation power on the defect formed by thermal exposure to the optical fiber increases. It has been established that with the same power loss on a defect formed by thermal action, the optical radiation power removed from such a defect has the greatest value when using G652 optical fiber, and the least when using G657 fiber. The scientific novelty of the work consists in the study of previously unexplored properties of optical fiber inhomogeneities caused by thermal exposure. Practical Significance. The results presented in the article can be used in the design of information protection systems transmitted over fiber-optic communication lines.