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Calcimator

OTDR Trace Analyzer Calculator

Analyze OTDR measurement results to identify event losses, compare against thresholds, and validate fiber link quality.

Inputs

km
dB

Results

Total Event Loss

1.5 dB

Overall Attenuation

0.5 dB/km

Loss Margin

0.9 dB

Expected Cable Loss3.5 dB
Avg Connector Loss0.525 dB
Avg Splice Loss0.112 dB
Max Acceptable Loss5.9 dB
Passed (1=Yes, 0=No)1
How to Use This Calculator
  1. Enter Fiber Length (km) and Total End-to-End Loss (dB) from the OTDR trace.
  2. Enter Total Events — the number of reflective and non-reflective events identified on the trace.
  3. Break down events into Reflective Events (connectors, mechanical splices) and Non-Reflective Events (fusion splices).
  4. Select the Test Wavelength — 1 for 1310 nm (0.35 dB/km) or 2 for 1550 nm (0.22 dB/km) — matching the wavelength used during the OTDR test.
  5. Review Overall Attenuation (dB/km), Loss Margin (dB), and Passed (1=Yes) — if the link fails the budget, investigate high-loss events.

How the result changes with Total End-to-End Loss

Total End-to-End LossTotal Event LossOverall AttenuationLoss Margin
62.5 dB0.6 dB/km-0.1 dB
2117.5 dB2.1 dB/km-15.1 dB
3935.5 dB3.9 dB/km-33.1 dB
5450.5 dB5.4 dB/km-48.1 dB

What each input means

Fiber Length
Total measured fiber length from OTDR trace
Total End-to-End Loss
Total measured loss from OTDR or power meter
Total Events
Total number of events detected in OTDR trace
Reflective Events
Events with reflectance (typically connectors or mechanical splices)
Non-Reflective Events
Events without reflectance (typically fusion splices or bends)
Test Wavelength
1=1310nm (0.35 dB/km), 2=1550nm (0.22 dB/km)

How this is calculated

Formula

Event Loss = Total Loss - (Fiber Length × dB/km)

Worked example, using the default values

  1. Identify Input Parameters
    4 parameters
    Fiber Length = 10, Total End-to-End Loss = 5, Total Events = 6, Reflective Events = 2 = 6 input(s) provided
  2. Calculate Total Event Loss
    Total Event Loss
    1.5 = 1.5
  3. Calculate Overall Attenuation
    Overall Attenuation
    0.5 = 0.5
  4. Calculate Loss Margin
    Loss Margin
    0.9 = 0.9
  5. Calculate Expected Cable Loss
    Expected Cable Loss
    3.5 = 3.5
  6. Calculate Avg Connector Loss
    Avg Connector Loss
    0.525 = 0.525

Engine last updated . Checked against 3 independently-derived tests — how we verify calculators.

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