Fusion splicing is the most common and effective method for splicing optical cables. It involves precisely aligning and then melting the ends of the fibers together, creating a continuous light path.
Here's a simplified overview of the fusion splicing process:
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Preparation:
- Fiber Stripping: Remove the protective coating layers (jacket, buffer) from the fiber ends to expose the bare glass. This requires specialized fiber stripping tools to avoid damaging the delicate glass.
- Fiber Cleaning: Thoroughly clean the bare fiber with isopropyl alcohol and lint-free wipes to remove any contaminants (dirt, oil) that can compromise the splice.
- Fiber Cleaving: Precisely cleave (cut) the fiber ends with a fiber cleaver. A good cleave is essential; it should be perfectly perpendicular to the fiber axis and have a smooth, flat surface. An angled or rough cleave will result in high insertion loss.
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Fusion Splicing:
- Fiber Placement: Carefully place the prepared fiber ends into the fusion splicer. The splicer has clamps to hold the fibers in precise alignment.
- Fiber Alignment: The fusion splicer automatically aligns the fiber cores using a microscopic viewing system. This alignment is critical for minimizing signal loss. The splicer may perform core alignment (aligning the cores) or clad alignment (aligning the outer cladding of the fibers).
- Fusion: The splicer uses an electric arc to heat and melt the fiber ends together. The heat fuses the glass, creating a permanent bond. The fusion parameters (arc power, duration) are automatically controlled by the splicer and depend on the type of fiber being spliced.
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Protection:
- Proof Testing: Some splicers automatically perform a proof test to ensure the splice has sufficient tensile strength.
- Splice Protection: Place a heat-shrink splice protector over the splice area to protect it from mechanical damage and environmental factors. The protector is typically a small plastic sleeve with a heat-shrinkable tube.
- Heat Shrinking: Slide the splice protector into the heating chamber of the fusion splicer to shrink the tube, providing a secure and robust covering for the splice.
Why Fusion Splicing?
Fusion splicing offers several advantages over other splicing methods:
- Low Loss: Provides the lowest insertion loss (typically around 0.02 dB) compared to other methods.
- High Strength: Creates a strong and durable connection.
- Permanent Connection: Offers a reliable, long-lasting connection.
- Consistent Performance: Produces consistent results when performed correctly.
Tools and Equipment:
- Fiber Stripper: Removes the protective coatings from the fiber.
- Fiber Cleaver: Provides a precise, clean cut of the fiber end.
- Fusion Splicer: Aligns and fuses the fiber ends.
- Fiber Cleaning Supplies: Isopropyl alcohol and lint-free wipes.
- Splice Protectors: Protect the completed splice.
Alternative Splicing Method: Mechanical Splicing
While fusion splicing is preferred, mechanical splicing offers a quicker, though typically less precise, alternative. Mechanical splices use a self-contained unit to align and join two fibers together, typically using an index-matching gel. This method generally results in higher insertion loss than fusion splicing.
