Fiber optic splicing with sheath involves securing the cable's outer layer while performing fusion or mechanical splices inside a protective closure.

Overview of Splice Closures

Fiber optic splice closures are designed to protect spliced fibers and maintain the integrity of the cable sheath. They can accommodate in-line, taut-sheath, and butt-splicing configurations and are suitable for both central tube and loose tube cables . Closures typically include a splice tray for storing fibers, splice holders for securing fusion splices, and multi-range grommets to fit various cable diameters . They are suitable for aerial, buried, and underground installations .

Sheath Retention and Splicing

When splicing with the sheath intact, closures often feature sheath retention systems and central strength member fastenings to prevent cable movement and maintain mechanical integrity . This is critical for taut-sheath applications, where the cable is under tension. Proper retention ensures that the fibers are not stressed and that the splice remains stable over time.

Splice Methods

• Fusion Splicing: Uses a core alignment splicer, such as the Fujikura 90S+, which aligns fiber cores precisely and applies a protective sleeve over the splice point. Automated features allow for consistent low-loss splices without manual intervention once the process starts .
• Mechanical Splicing: Uses splice holders within the tray to align fibers without fusion. Some closures provide accessory kits for storing mechanical splices, typically up to 24 per kit .

Installation Considerations

• Bending Radius: Maintain a minimum bending radius of 10 times the cable diameter for unarmored cables and 15 times for armored cables to prevent fiber damage .
• Environmental Protection: Closures are sealed with silicone rings or other gaskets to protect against moisture and contaminants. Some closures, like Corning's Multipurpose Enclosure (MPE), allow for incremental connections and can house optical splitters for PON architectures .
• Capacity: Closures vary in capacity; for example, a six-tray closure can handle up to 144 splices, with each tray accommodating 24 splices .

Practical Tips

• Ensure the sheath is properly secured before splicing to prevent movement.
• Use appropriate grommets and clamps for the cable type and diameter.
• Organize fibers neatly in the splice tray to allow for future maintenance.
• For high-fiber-count applications, consider closures that allow stacked trays and incremental drop connections. By following these guidelines, fiber optic splicing with sheath can be performed efficiently while maintaining cable integrity and long-term reliability .