Optical cables are classified by structure into stranded, bundle, skeleton, ribbon, single-tube, and multi-unit types, each designed for specific fiber counts, flexibility, and deployment scenarios.

Stranded Optical Cable

Stranded optical cables feature a central strength member around which multiple optical fibers or fiber ribbon sub-units are helically twisted (S twist or SZ twist). This design allows for high fiber counts and flexibility, making it suitable for long-distance or high-capacity networks. Color-coded loose tubes help distinguish fibers and sub-units, facilitating installation and maintenance .

Bundle Type Optical Cable

In bundle type cables, a single loose tube is placed at the center, containing the optical fibers or ribbons without twisting. The strengthening members are located around the tube. These cables typically have fewer than 12 cores and are ideal for smaller-scale deployments or short-distance applications .

Skeleton Optical Cable

Skeleton cables use a plastic skeleton with grooves to hold fibers or ribbons, which are helically twisted into the grooves. The reinforcing member is at the center, providing structural support. This design balances fiber protection with flexibility and is often used in environments requiring moderate fiber counts .

Ribbon Fiber Optic Cable

Ribbon cables arrange multiple primary-coated fibers in a flat ribbon unit, which is then placed into a plastic sleeve or groove. Ribbon units can form central bundled tubes, skeleton structures, or layered designs, allowing for high-density fiber deployment and efficient mass fusion splicing .

MPO Pre-Terminated Cables

MPO (Multi-fiber Push On) cables are classified into single-tube trunk cables and multi-unit trunk cables. Single-tube cables concentrate all fibers in one protective tube, offering compact design and high fiber density. Multi-unit cables combine multiple independent fiber units (e.g., 12- or 24-fiber subunits) into a larger assembly, providing flexibility and scalability for high-density networks .

Summary

The structural classification of optical cables determines their fiber capacity, flexibility, and suitability for different applications. Stranded and ribbon cables are preferred for high-capacity or long-distance networks, bundle and skeleton types for smaller-scale or moderate fiber counts, and MPO pre-terminated cables for high-density, modular deployments. Each structure is designed to optimize mechanical protection, installation ease, and network performance .