What are the advantages and disadvantages of using mechanical splices versus fusion splices?

Mechanical splices and fusion splices are two different methods for joining optical fibers, each with its own advantages and disadvantages. A mechanical splice uses a self-contained assembly to align and hold two fibers together, typically using an index-matching gel to reduce Fresnel reflection. A fusion splice, on the other hand, uses heat to fuse the two fibers together, creating a permanent bond. One advantage of mechanical splices is their ease and speed of installation. Mechanical splices require minimal equipment and can be installed quickly in the field, making them suitable for temporary repairs or quick connections. No specialized training is required. Fusion splicing requires a fusion splicer, which is an expensive piece of equipment that requires trained personnel to operate. A disadvantage of mechanical splices is their higher insertion loss compared to fusion splices. Mechanical splices typically have an insertion loss of 0.3 dB to 0.75 dB, while fusion splices can achieve losses of 0.1 dB or less. The higher loss in mechanical splices is due to imperfections in the alignment and the presence of the index-matching gel. Another advantage of fusion splices is their superior long-term reliability. Fusion splices create a permanent bond between the fibers, resulting in a more stable and durable connection. Mechanical splices are more susceptible to degradation over time due to changes in temperature or humidity. Mechanical splices also have a higher reflectance than fusion splices because a perfect physical connection doesn't happen as it does in fusion splicing. A disadvantage of fusion splicing is that it is less flexible than mechanical splicing. Once a fusion splice is made, it cannot be easily undone. Mechanical splices can be re-entered and re-spliced if necessary. Mechanical splices are suitable for applications where quick installation and ease of use are more important than low loss and long-term reliability, such as temporary repairs or short-term installations. Fusion splices are preferred for applications where high performance and long-term stability are critical, such as in backbone networks or long-haul links. For example, a mechanical splice might be used to quickly restore service after a cable cut, while a fusion splice would be used for a permanent repair in a high-speed network.