Yamasaki Y30 Series User Manual page 23

average loss of optical fiber measured
the optical fiber
b. Too long trailing at the front
measured
end of the test curve
The fiber end face is
contaminated;
The fiber end face inside the
There is only
connector at the fiber output
the front end
end of the instrument is
reflection peak
contaminated.
other than the
The ceramic core in the
test waveform
connector (ring flange) at the
on the screen,
fiber output end is damaged,
or the trailing of
cracked or broken.
the front end
The optical fiber connector is not
reflection peak
matched
is too long.
5.6 Cause for curve test and analysis failure
In case of big difference between the curve test and analysis result and that expected, or no
expected result obtained, the cause can be one of the following:
 No test curves of the optical fiber are obtained.
If there is only front end reflection peak rather than linearity curve reflecting the fiber
properties for the test curve, check the following:
Whether the end face type of the optical fiber under test is consistent with that at the
fiber output port of the OTDR.
Whether the fiber end face is contaminated.
Whether the OTDR fiber output ring flange is damaged.
Use the VFL function to check there is any high loss at the near end of the optical fiber link
under test.
 There is severe trailing at the near end of the test curve.
If any severe trailing is found at the falling edge of the near-end reflection peak of the test
curve, try to solve the problem as follows:
Clean the end face of the optical fiber under test and the end face of the fiber output end
with the absorbent ball dipped with proper absolute ethyl alcohol.
Test the curve again with small pulse width (select the average test mode and set certain
average times in this case).
optical fiber length accurately.
b. Clean the connector of the optical fiber
under test or add a little matching solution,
and then test the curve again.
Wipe the fiber end face clean with absolute
ethyl alcohol.
Take out the connector at the fiber output
end, and wipe the fiber end face clean with
absolute ethyl alcohol.
Change the ring flange.
The end face type of the optical fiber
connector under test must match that in the
OTDR optical output connector. Otherwise,
the patch cord must be used for through
connection.
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