METHOD OF CONTROL THE MECHANICAL STATE OF THE OPTICAL FIBER OF THE DIELECTRIC SELF-SUPPORTING OPTICAL CABLE DURING OPERATION
Authors: Bondarenko O. V. , Stepanov D. M. 
Published: December 2024

Context. One of the issues of theoretical and practical research studying phenomena that occur over time and lead to violations of the normative work of optical cables (OC) are ways to ensure and control their reliability during operation.
Today, electronic communication (telecommunications) has already gained significant integration and widespread use due to the urgent need to exchange large volumes of information between users or network devices at high speeds and over long distances, as well as the provision of a wide range of electronic communication services.
The electronic communication service has a high level of demand and consists in receiving and/or transmitting information through electronic communication networks, which is transmitted using electronic communication networks and services.
In an electronic communication network, the transmitting/receiving of optical signals is provided by the fiber optic transmission system (FOTS). It is capable of converting electrical signals from a variety of digital devices into optical signals and transmitting them over fiber-optic communication lines (FOCL), which is the main transmission medium in an electronic communication network.
The problem of ensuring the reliability of the FOCL, which includes a wide range of issues related to the development and production of all its elements, design, construction and technical operation of the communication line, continues to gain more and more importance.
In general, the transmitting/receiving of information between end users equipment, communication nodes, network devices (servers, databases, etc.) takes place through an electronic communication network.
Normative and technical documentations for fiber-optic communication lines regulates the control of the mechanical state of the optical cable during operation, but do not provide the full control of the mechanical state of the optical fiber to ensure the quality and reliability of the line during the specified service life.
As known, to ensure the reliability of the optical cable, as a rule, the permissible elongation of the optical fiber (OF) is ɛpOF < (0.2...0.25) %, adopted during the designing of the cable. However, during operation, the appearance of multiple excess of elongations exceeding these values is possible in the fibers.
Thus, the development and substantiation of methods for evaluating the mechanical characteristics of a dielectric self-supporting optical cable (DSOC) and the method of full control of the mechanical state of the optical fiber is necessary. The last can lead to premature failure of the optical fiber.
Objective. Development and substantiation of the method of control the mechanical state of an optical fiber of the suspended DSOC, as well as assessment of the conditions of deformation of optical fibers in its core with the appearance of longitudinal tensile/compressive loads during operation.
Method. Two ways of evaluating the mechanical characteristics of DSOC and the method of control the mechanical state of its fibers have been developed and proposed. For this, the following characteristics of the cable and fiber are adopted in the work: relative elongation of the cable and fiber (ɛcх, ɛОFх), span length (Lsх) of the line, cable sag in the span (fx) and tensile load (TL) of the cable (Ftlх), which causes longitudinal deformation ɛ. At the same time, the method proposes to control the mechanical state of the optical fiber during the operation of the DSOC by determining its effective relative elongation according to the mechanical, physical and climatic conditions of the line location.
In the paper, it is proposed to measure and calculate the following mechanical characteristics, due to the developed reference data for the selection of the cable type and the climatic zone of the line location, measuring equipment and mathematical tools:
– equivalent mechanical tension in DSOC;
– calculated and actual cable sag in the span;
– actual effective relative elongation of the cable;
– actual tensile load acting on the cable.
The ways and method presented in the work allow a complete evaluation of the mechanical characteristics of the cable and control of the mechanical state of the optical fiber during operation of the DSOC. It creates an opportunity to monitor its changes to prevent the appearance of excessive loads during operation and failure of the fiber-optic communication line.
It is possible to recommend this method for use by relevant departments for technical operation of telecommunication lines and networks based on hanging optical cables.
Results. The work presents the results of the development and justification of the method of control the mechanical state of optical fibers of dielectric self-supporting optical cables during operation. For example, using the developed method, it is shown that in the cable OKL-3-D2A14 produced by PJSC “Odeskabel” in the conditions of the Odesa climate zone (Black Sea region), optical fibers with a span length of 100 m are subject to elongation by 0.16 %, and DSOC is subject to an actual tensile force of 2.722 kN. This result of the control of the mechanical state of the OF established that such span of the line ensures its mechanical integrity within the limits of the permissible deformation of 0.25 % adopted in the design of the cable, but exceeds its permissible tensile load of 2.6 kN.
Conclusions. The scientific novelty of the work results is that, for the first time ways of fully evaluating the mechanical characteristics of the DSOC during operation and the method of fully control the mechanical state of its optical fiber have been developed. It allows to monitoring changes in the mechanical state of the optical fiber of the cable.