Example OTDR Trace (Click to Enlarge)
Reading an OTDR Trace: A Step-by-Step Guide
Which Wavelength Report to Use?
▪ Single-Mode (OS2): Use 1550nm for sensitivity to bends/losses; compare with 1310nm for confirmation.
▪ Multi-Mode (OMx): Use 850nm for worst-case; 1300nm for comparison.
Key Features to Identify (using an OS2 1550nm report as an example):
1. Launch Event (Event 1 at 0m, reflectance -31.82 dB)
OTDR connection—baseline, ignore for link analysis.
2. Fusion Splice (Event 2 at 216.93m, loss 0.064 dB, no reflectance)
Low loss, no reflection—good splice.
3. Fusion Splice (Event 3 at 2820.13m, loss 0.042 dB)
Excellent low loss.
4. Gain Artifact (Event 4 at 4741.9m, loss -0.078 dB)
Negative loss from mismatch—inspect splice.
5-6. Fusion Splices (e.g., Event 5 at 5016.26m, loss 0.111 dB)
Typical low-loss splices.
7. Possible Splice/Bend (Event 7 at 7822.36m, loss 0.183 dB)
Moderate loss—check.
8. End of Fiber (Event 8 at 7822.36m, loss 0.150 dB)
Final drop, total loss 1.668 dB.