ESTIMATE OF THE EFFECT OF EXTERNAL ELECTROMAGNETIC-FIELDS IN THE CHOICE OF CONSTRUCTION OF AN OPTICAL CABLE WITH METALLIC ELEMENTS

At the present time the following design versions are known for optica l cables (OC): containing metallic elements (conductors, armoring wire s, lead or aluminum claddings) or completely dielectric (with no metal ). The advantages of the former include high mechanical strength and m oisture resistance. Service communications can be carried out along th e copper conductors, they can be used for a remote power supply of the line regenerators and to locate the buried cable. However, such cable s are vulnerable to electromagnetic effects (thunderstorms, etc.) and have a greater mass and size. The latter version is free from electrom agnetic effects and corrosion but is not as mechanically durable nor m oisture resistant and it is subject to attack by rodents. It is diffic ult to locate the path of these cables and a separate electrical insta llation is required to supply the regenerators. In principle, both opt ical cable designs have come into widespread use in the communication networks of our country. However, the advisability of using one or ano ther metallic element must be justified by a calculation. Moreover, th e optimum conditions for placement of the metallic elements inside the cable as well as the restrictions on the use and laying of these cabl es under ambient conditions must be determined [1-3].