IL @ 1550 higher than 1310

A connector, or an entire product design, showing a significantly higher Insertion Loss at 1550 than at 1310 indicates the likely presence of a stress point on the fiber somewhere in the cable assembly—most likely a fiber bend that exceeds operating bend radius, or a fiber “pinch” or microbend somewhere within the product.  The higher the stress (larger the bend), the higher the Insertion Loss @ 1550 compared to 1310.   But whereas a core-offset problem mentioned above are often normal results of raw-material selection, any excess stress directly on a fiber represents a serious risk to product reliability, and thus IL values @ 1550 are particularly important to monitor and troubleshoot.

Even with advent of “reduced bend radius” fiber, it is excellent practice to test all products at 1550.    Doing so may identify a serious product flaw, particularly in products which have fiber routed within an enclosure (such as within a cassette or a cabinet or a ribbon fan-out transition).    If your product Insertion Loss @ 1550 is significantly higher than @1310, you very likely have a product with fiber under stress, and you need to understand the cause.


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



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