Method for splicing 72-core optical fiber cables

Fusion splicing is the preferred method for 72-core optical fiber cables, providing low-loss, permanent connections with high reliability.

Overview

Splicing a 72-core fiber cable involves joining multiple individual fibers within a single cable, ensuring minimal signal loss and back reflection. Due to the high fiber count, fusion splicing is generally recommended over mechanical splicing because it produces permanent, low-loss joints suitable for long-haul or high-performance networks, while mechanical splicing is better suited for temporary or emergency repairs .

Preparation Steps

1. Cable Preparation: Strip the outer jacket and buffer layers carefully to expose the individual fibers. Ensure fibers are clean and free of dust or oil, as contaminants can increase splice loss .
2. Fiber Cleaving: Use a precision fiber cleaver to create perpendicular, smooth fiber ends. Accurate cleaving is critical for low-loss fusion splices .
3. Protective Sleeves: Place heat-shrink protective sleeves on each fiber before splicing to safeguard the joint after fusion .

Fusion Splicing Procedure

1. Align Fibers: Insert the cleaved fibers into a fusion splicer. Modern splicers use core or cladding alignment technology to precisely align the fiber cores .
2. Fusion Process: The splicer generates an electric arc to melt and fuse the fiber ends, creating a continuous optical path. Typical splice loss is 0.02–0.1 dB, ensuring minimal signal degradation .
3. Splice Protection: After fusion, slide the protective sleeve over the splice and shrink it using a heat source. This provides mechanical strength and environmental protection .
4. Testing: Verify the splice quality using a Visual Fault Locator (VFL) or Optical Time Domain Reflectometer (OTDR) to ensure proper alignment and low insertion loss .

High-Density Considerations

• Ribbon or Mass Fusion Splicing: For 72-core cables, consider ribbon fiber splicing, which allows multiple fibers (e.g., 12 fibers per ribbon) to be spliced simultaneously, reducing time and improving consistency .
• Splice Trays and Closures: Organize splices in splice trays within a splice closure to protect fibers and maintain bend radius, preventing microbends or stress on the fibers .
• Labeling and Documentation: Clearly label each fiber and document the splice sequence to simplify troubleshooting and future maintenance .

Mechanical Splicing (Optional)

Mechanical splicing can be used for temporary connections or emergency repairs. Fibers are aligned in a mechanical fixture with an index-matching gel to reduce light loss. Typical loss is higher (0.2–0.75 dB) and long-term reliability is lower, making it less suitable for permanent 72-core installations .

Best Practices

• Work in a clean, dust-free environment to prevent contamination.
• Use high-quality cleavers and splicers calibrated for multi-core fibers.
• Maintain consistent fusion parameters for all fibers to ensure uniform performance.
• Protect splices with heat-shrink sleeves and organize them in splice trays to prevent mechanical stress . By following these steps, a 72-core optical fiber cable can be spliced efficiently, ensuring low-loss, high-reliability connections suitable for telecom, data center, or long-haul network applications.