Kingfisher KI7300 Series, Operation And Maintenance Manual

Page: 26 / 66

ACCURACY CONSIDERATIONS
KI7000 UM-5
-
24 -
Keep optical connectors clean and in good condition.
To reduce the effect of polarisation changes, the fiber system should
be neat, coiled and physically stable.
In multimode systems, modal noise and general uncertainty are
much worse than in single mode systems. Optimum measurement
repeatability will be obtained by use of a mandrel wrap.
Power Meter:
Using an APC connector at the power meter interface will allow to
reduce line reflections and to improve measurement stability in the
laser based single mode systems. This is important when measuring
small connector losses.
Light Source:
Light source power may drift. When you have finished a test, go back
to the start position to check if the light source power is still within
acceptable limits. Note that specifications are for typical drift and
warm up period, but the actual drift will vary between instruments
and test situations.
With exception of KI7300C and KI7400C Series, most available laser
sources are sensitive to reflections. Varying reflections can induce
laser source instability of around 0.3 dB. This is very difficult to verify
without a special test system, but can cause errors. Reduced
reflection will result in improved repeatability.
Due to emitter center wavelength uncertainty (eg ± 20 nm), fiber
attenuation may vary with different light sources.