The advent of computer networks in more and more areas of our daily lives, constantly increases information traffic volumes and requirements for reliability and security for the portable environments. Copper wires and computer networks built on their base continue to grow, but the growth in demand for spare capacity exceeds their capabilities. Often laying new cables to answer the network needs can be more expensive than a single fiber optic cable with large capacity.
The optical fibers are increasingly preferred because they provide very wide bandwidth, while also cover large distances with minimal signal degradation. The principle of transmission of light in the fiber uses the effect of total internal reflection, which is achieved by two layers – core and an outer layer, with different refractive index.
Today we can achieve distances without intermediate amplifiers in the range of 200 to 300 Km. In practice, urban trails to be built up to 10 kilometers. The low weight of the optical cable and the small diameter facilitate its installation in a variety of conditions. With optics interception of the transmitted information is much harder than with copper cables using electrical signals. Since an external device will interrupt the light path, any listening device can be easily detected. Therefore, optical networks are preferred for building classified networks in government and military organizations.