The Structure Of Fiber Optic Cables

The fiber optic cable has of several layers:

• The outer, colored sheath is for identification, protection against mechanical damage, and temperature protection.
• The black, inner sheath protects the core against light radiation from the outside.
• Cladding (fluorinated polymer) is a layer around the core with a lower refractive index to light. It has a thickness of a few μm (micrometers) and reflects light back to the core, preventing loss of light from the core at the "edges".
• The core is the central part of the fiber optic cable. It is made of specially conditioned Plexiglas. It transmits light with almost no loss.