EXFO FTB-5700 Single Ended Dispersion Analyzer for FTB-200 v2 - Manual (Page 78)

Troubleshooting
72 FTB-5700
Solving Common Problems
CD-Related Problems
Message Possible cause Solution
Conditions are not
optimal for measuring
chromatic dispersion.
Cannot achieve good
measurement quality.
³
Too much loss in
the fiber under test.
³
Multiple strong
reflections close to
each other at the
end of fiber.
³
Clean the fiber end.
³
Add a reflective termination at
the end of the fiber.
³
In this case, add a receive fiber
of at least 200 m. This will
remove that condition.
There are not enough
points to compute the
model fit. Use a lower
order fiber model.
The wavelength range
is too big.
Reduce the wavelength range in the
Acquisition tab of the Setup
window, or select Default as the
wavelength range value.
To reduce the constraints on the fit,
it may be possible, if applicable, to
lower the fit model order (for
example, select a 3-term Sellmeier
instead of a 5-term Sellmeier
model).
There are not enough
valid points to compute
the model fit due to low
power conditions in the
selected range.
³
Too much loss in
the fiber under test.
³
The wavelength
range is unsuitable
for this FUT.
³
Clean the fiber end.
³
Add a reflective termination at
the end of the fiber.
³
Select a wavelength range that
suits the FUT and the instrument
range. You can set the
wavelength range in the
Acquisition tab of the Setup
window.