Core-alignment fusion splicers are typically used for multimode optical cables to ensure precise alignment and low splice loss.

Recommended Splicer Type

For multimode fibers, core-alignment (profile-alignment) fusion splicers are preferred. These splicers use cameras and software to detect the fiber cores and automatically align them with submicron precision, ensuring minimal light loss and high reliability . While multimode fibers have larger cores than singlemode fibers, precise alignment is still important to reduce insertion loss, which is typically below 0.1 dB for multimode splices .

Alignment Techniques

• Core Alignment (Profile Alignment): Uses multiple cameras to image the fiber cores from different angles. The splicer adjusts the fiber positions in multiple axes to achieve optimal core-to-core alignment . This method is highly effective for multimode fibers, especially when fibers from different manufacturers or with graded-index profiles are used .
• Cladding Alignment: Aligns fibers based on the outer diameter (cladding) rather than the core. This method is simpler and less expensive but may result in slightly higher splice loss (~0.1 dB) and is generally used for short-distance or low-demand multimode applications .

Practical Considerations

• Fiber Preparation: Proper stripping, cleaning, and cleaving of the fiber ends are critical. A high-precision cleaver is required to ensure a smooth end face, which directly affects splice quality .
• Splice Protection: After fusion, a heat-shrink sleeve is applied to protect the splice from environmental factors such as moisture and mechanical stress .
• Machine Settings: Most modern fusion splicers allow preset parameters for multimode fibers. Following manufacturer recommendations ensures consistent low-loss splices .

Summary

For multimode optical cables, core-alignment fusion splicers are the most suitable choice due to their precision and reliability. Cladding-alignment splicers can be used for simpler, short-distance applications, but core alignment provides the best performance, especially in professional or high-speed network environments . Proper fiber preparation and adherence to splicer instructions are essential for achieving optimal results.