Loose tube stranded optical cable

Loose tube stranded optical cables are designed for robust fiber protection in outdoor and industrial environments, featuring multiple water-blocked tubes stranded around a central strength member.

Construction and Design

Stranded loose tube cables consist of optical fibers housed in individual loose tubes, typically made of high-modulus plastic and filled with water-blocking yarns or gels to prevent moisture ingress. These tubes are stranded around a central strength member, which provides mechanical support and flexibility, forming the cable core. The core is then wrapped with water-blocking tape and sheathed with polyethylene (PE) or other protective jackets, sometimes armored with laminated aluminum or corrugated steel for additional protection.

Nylon or LSZ

H jackets may be used for UV resistance or industrial safety.

Fiber Arrangement

Unlike central loose tube cables, which contain all fibers in a single large tube, stranded loose tube cables have multiple smaller tubes, each typically containing up to 12 fibers. This design allows for point-to-point and point-multipoint installations, where spur cables can be spliced from the backbone, and provides better flexibility and strain relief during installation.

Applications

Stranded loose tube cables are ideal for short and long-haul backbone applications, suitable for in-duct installation or direct burial. They are commonly used in industrial environments, where LSZH (low-smoke zero-halogen) versions provide safety benefits by reducing toxic gas emissions in case of fire. These cables are also designed to withstand extreme temperatures, chemical exposure, and mechanical stress, making them suitable for harsh outdoor or plant-floor conditions.

Environmental and Safety FeaturesWater-blocking: Dry core or gel-filled tubes prevent water penetration and fiber damage.

U

V protection: Nylon jackets are UV-stabilized, and additional PE sheaths are recommended for direct sunlight exposure. Temperature range: Typically -40℃ to +70℃ for transport and storage. Industrial safety: LSZH jackets reduce halogen-related hazards in case of fire.

Summary

Stranded loose tube optical cables combine mechanical strength, environmental protection, and flexible fiber management, making them suitable for backbone networks, industrial installations, and outdoor deployments. Their multi-tube design, water-blocking features, and protective sheaths ensure reliable performance in harsh conditions while supporting easy fiber identification and splicing during installation.