The structure of GYTA optical cable is that single-mode or multi-mode optical fiber is sheathed in a loose tube made of high modulus polyester material, and the tube is filled with waterproof compound. The center of the cable core is a metal reinforced core. Stranded loose tube:high modulus plastic,filled with tube Optical fiber, formally known as optical waveguide fiber, is a dielectric waveguide that transmits information in the form of light pulses. It is the cornerstone of virtually all high-bandwidth, long-distance communication networks today. With metallic central strength offers ease of location while dielectric grounding issues.