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18 Cleaning Connections for Accurate Measurements
best physically contacting connectors have return
losses better than 50 dB, although 30 to 40 dB is more
common.
Visual inspection of fiber ends
Visual inspection of fiber ends can be helpful. Contami-
nation or imperfections on the cable end face can be
detected as well as cracks or chips in the fiber itself.
Use a microscope (100X to 200X magnification) to
inspect the entire end face for contamination, raised
metal, or dents in the metal as well as any other imper-
fections. Inspect the fiber for cracks and chips. Visible
imperfections not touching the fiber core may not affect
performance (unless the imperfections keep the fibers
from contacting).
Cleaning Connectors
The procedures in this section provide the proper steps
for cleaning fiber-optic cables and Agilent universal
adapters. The initial cleaning, using the alcohol as a sol-
vent, gently removes any grit and oil. If a caked-on layer
of material is still present, (this can happen if the beryl-
lium-copper sides of the ferrule retainer get scraped
and deposited on the end of the fiber during insertion of
the cable), a second cleaning should be performed. It is
not uncommon for a cable or connector to require more
than one cleaning.
C A U T I O N
Agilent Technologies strongly recommends that index
matching compounds
not be applied to their
instruments and accessories. Some compounds, such as
gels, may be difficult to remove and can contain
damaging particulates. If you think the use of such
compounds is necessary, refer to the compound
manufacturer for information on application and
cleaning procedures.