How to weld the protective sleeve of a cap-type optical cable splice closure

To weld the protective sleeve of a cap-type optical cable splice closure, first prepare and clean the fibers, perform fusion splicing, then insert the splice into the protective sleeve and heat it to shrink and secure the sleeve around the splice.

Step 1: Prepare the Fiber Optic Cable

• Strip the coating: Use a wire stripper to carefully remove the protective coating from the fiber, exposing the bare fiber. The stripping length should match the sleeve and closure requirements, typically a few centimeters to over ten centimeters depending on the design ( ).
• Clean the fiber: Wipe the exposed fiber with alcohol cotton to remove dust, grease, or other contaminants ( ).
• Cut the fiber: Use a precision fiber cleaver to cut the fiber ends cleanly, ensuring flat, perpendicular surfaces to avoid signal loss ( ).

Step 2: Fusion Splicing

• Align the fibers: Place the prepared fiber ends into the fusion splicer fixture, ensuring proper alignment of the cores ( ).
• Perform the weld: Activate the fusion splicer to weld the fibers. Monitor the splicer display to confirm a high-quality splice with minimal loss ( ).
• Remove the fused fiber: Once welding is complete, the splicer will push out the fused fiber for sleeve installation ( ).

Step 3: Install the Protective Sleeve

• Select the appropriate sleeve: Choose a heat-shrink or cap-type protective sleeve that matches the fiber diameter and splice type ( ).
• Slide the sleeve over the splice: Carefully position the sleeve so it fully covers the welded joint ( ).
• Heat the sleeve: Use a heat source, such as a fusion splicer oven or heat gun, to evenly heat the sleeve. The sleeve material will shrink and conform tightly around the splice, providing mechanical protection and environmental sealing ( ).
• Ensure proper fit: Check that the sleeve is smooth, fully contracted, and free of voids or bubbles ( ).

Step 4: Place the Sleeve in the Splice Closure

• Insert into the tray: Place the protected splice into the fiber optic splice tray inside the closure, coiling the fiber in a figure-8 pattern with a minimum bend radius of 30 mm to prevent stress ( ).
• Secure the tray: Fasten the tray holder and close the splice closure, ensuring all cable entrances are sealed with plugs and screws tightened ( ).
• Check sealing: If the closure uses protective gas, release any excess gas and verify the closure is airtight ( ).

Step 5: Test the Splice

• Visual inspection: Confirm the sleeve fully covers the splice and the fiber is properly aligned ( ).
• Performance testing: Use an OTDR or other optical testing equipment to verify signal integrity and ensure the splice meets transmission requirements ( ).

Precautions

• Avoid bending or stressing the fiber during preparation and installation.
• Ensure the heating process is controlled to prevent overheating or damaging the fiber.
• Keep all components dry and clean to maintain splice quality ( ). Following these steps ensures that the protective sleeve is properly welded, providing mechanical strength, environmental protection, and reliable optical performance.