The cable core structure should meet the following basic requirements:

① Make the optical fiber in the best position and state in the cable to ensure stable optical fiber transmission performance. When the optical cable is subjected to certain external forces such as pulling, lateral pressure, etc., the optical fiber should not be affected by external forces.

② The reinforcing elements in the cable core should be able to withstand the allowable tensile force.

③ The cross section of the cable core should be as small as possible to reduce the cost. There are optical fibers, sleeves or skeletons and strengthening elements in the cable core, and the cable core needs to be filled with ointment, which has reliable moisture-proof performance and prevents moisture from spreading in the cable core.