Splicing loose tube stranded optical cables requires careful preparation, buffer tube management, and adherence to safety and handling procedures to ensure minimal signal loss and long-term reliability.

Cable Structure and Preparation

Loose tube stranded cables consist of optical fibers enclosed in buffer tubes, which are stranded around a central strength member and protected by a water-blocked, dry core and an outer polyethylene (PE) or UV-stabilized nylon jacket . Before splicing, the cable must be properly stripped, exposing the buffer tubes without damaging the fibers. The minimum bend radius during installation is typically 20 times the cable diameter under tension and 10 times for long-term static conditions .

Safety Precautions

Always wear safety glasses and gloves, work in a well-ventilated area, and avoid looking directly into fiber ends that may carry laser light, as this can cause serious retinal damage . Solvents should be used carefully, and magnifiers should not be used in the presence of laser radiation.

Buffer Tube Management

After stripping the outer sheath, buffer tubes should be looped and secured in the splice tray to accommodate movement of up to 10 mm (0.4 inches) within closures . This prevents stress on the fibers and ensures proper alignment during splicing. The central member and tensile strength elements should be clamped to prevent pistoning or contact with fibers .

Splicing Procedure

1. Prepare the fiber ends by carefully stripping the buffer coating and cleaning the fibers with appropriate solvents.
2. Organize fibers in the splice tray, ensuring each fiber is properly routed to avoid microbends or stress.
3. Fusion splicing is commonly used for loose tube cables. Each fiber is spliced individually, unlike ribbon cables where mass fusion splicing can handle multiple fibers simultaneously .
4. Protect the splice using heat-shrink sleeves or mechanical protection within the splice tray.
5. Re-secure buffer tubes and cable sheath to maintain strain relief and prevent movement that could increase attenuation .

Additional Considerations

• Loose tube cables often include excess fiber length (2–8%) to reduce tension effects during installation .
• Metallic components, such as armoring or steel central members, should be properly grounded to the closure or grounding conductor .
• For high-fiber-count cables, splicing can be time-intensive; planning and organization are critical to minimize downtime and maintain network performance . By following these steps and adhering to manufacturer guidelines, loose tube stranded optical cables can be spliced efficiently while maintaining low attenuation, mechanical stability, and long-term reliability.