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COURSE DEMO Page 8 of 12

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Troubleshooting

Bad Splice, or Bend in the Tray?

Fusion splice	Splice with bend
Splice with bend loss at 1310nm	Splice with bend loss at 1550nm

The knowledgeable OTDR operator can determine whether a splice showing excessive loss is truly a poor splice, or whether there is a bend radius violation in the splice tray that is causing the high loss reading.

Singlemode fusion splices will generally read the same value when tested at both 1310 and 1550nm, provided that there are no bending problems for that fiber in the tray.

Because the 1550nm wavelength is much more sensitive to bend violations than 1310nm, if the splice displays much higher loss at 1550 than at 1310, a bend radius violation is most likely the cause. Removing the bending problem and retesting will usually result in an acceptable splice loss measurement.

LESSON REVIEW

Key Points:

1. Fusion splices will indicate roughly the same amount of loss when tested with an OTDR at both 1310nm and 1550nm.

2. If a splice shows substantially more loss at 1550nm, there is a strong possibility of a bend radius violation within the splice enclosure.