Main Components of National Optical Cable

A national optical cable contains ultra-pure glass or plastic cores that transmit data as light, surrounded by protective layers including cladding, coatings, strength members, and an outer jacket.

Core and Cladding

At the heart of the cable is the core, typically made of ultra-pure silica glass (SiO2) or sometimes plastic, which carries data-encoded light signals over long distances with minimal loss. Surrounding the core is the cladding, a layer with a lower refractive index that keeps light confined within the core through total internal reflection, ensuring efficient signal transmission.

Protective Coatings

Each fiber is coated with a plastic layer, often acrylate or polyimide, which protects the delicate glass from scratches, moisture, and environmental damage without affecting optical properties. This coating is critical to prevent signal loss and maintain the integrity of the light path.

Strength Members

To withstand tension, bending, and external forces, optical cables include strength members, which can be made of aramid yarn (like Kevlar), fiberglass, or steel rods. These components prevent stretching and mechanical damage, especially in long-distance or underground installations.

Outer Jacket

The cable jacket is the outermost layer, providing environmental protection against moisture, UV radiation, chemicals, and physical abrasion. Depending on the application, jackets may be designed for indoor, outdoor, or armored use, sometimes including steel or other materials for additional protection.

Fiber Types

National optical cables may contain single-mode fibers with a core diameter of 8–10 microns for long-distance, high-bandwidth transmission, or multimode fibers with cores of 50–62. 5 microns for shorter distances, such as within buildings or campuses. Modern cables can bundle hundreds or even thousands of fibers, often organized in ribbons or bundles for efficient splicing and network management.

Additional Features

Some cables include ripcords to facilitate jacket removal during installation or repair, and light-absorbing materials between fibers to reduce crosstalk in dense fiber bundles. These design elements ensure reliable, high-speed data transmission across national networks.