IL @ 1310 higher than 1550

A connector, or an entire product design, showing a significantly higher Insertion Loss at 1310 than at 1550 indicates a likely problem in core-to-core alignment between the two mated ferrules.   The difference may be small, and indeed may be acceptable.   The larger the misalignment, the more Insertion Loss @ 1310 compared to 1550.   The cause of the misalignment could be due to many factors, most often either contamination on the product and testing components, or poor fiber core-to-ferrule concentricity.

Contamination can hopefully be removed, and the preceding manufacturing process refined to eliminate prior to testing.   Poor concentricity, however, is often the result of using oversized ferrules, and thus the Insertion Loss cannot be improved without replacing the connector.   “Oversized” is relative:   the larger the ferrule hole bore is than the fiber OD, the most the fiber will be able to sit off to the side of ferrule center, and thus the larger the expected Insertion Loss @ 1310.


READ THE BLOG: Insertion Loss Troubleshooting Tip: Singlemode 1310 vs. 1550



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