Loose-tube optical cable 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 LSZH 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 Features

• Water-blocking: Dry core or gel-filled tubes prevent water penetration and fiber damage .
• UV 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 .