HP 70000 series, User Manual

Page: 392 / 447

5. Make the optical connection immediately or cover the connector for later use .
Note
Use a clean piece of cleaning tape to remove particles from the ber end
immediately before making each connection.
Using Index-Matching Compounds If Necessary
Note
It is strongly recommended that index-matching compounds not be applied to
HP instruments . If they are required, clean thoroughly after each use or attach
an HMS-10/HP adapter cable to the instrument with a dry connection and
make wet connections at the free end of the cable . Use of an index-matching
compound cannot x a damaged connector . Do not use gels containing
particulates , such as glass spheres , in physically contacting connectors .
In some circumstances , the use of index-matching compound can improve the connection. F or
example , an index-matching compound can ll the gap and make a smooth transition from ber
to ber in noncontacting connectors . Noncontacting connectors are connectors with concave
or recessed ber cores; the ber cores do not make contact at the connecting interface . An
index-matching compound can improve the performance of a physically contacting connector
that does not have acceptable return loss . In general, if a physically contacting connector
interface has a return loss of 30 dB or less in a dry condition, it should be inspected for
damage .
Many types of index-matching compounds are available to make wet connections: oil, gel,
and grease . Oil is often used on connecting interfaces where little or no air gap is expected.
However , oil has a tendency to ow or drip onto unwanted areas and cannot adhere as well to
the ber ends as gel. Gel is more viscous than oil but can be more dicult to remove . Also ,
some gels contain damaging particulates: read the technical specications .
If it should become necessary to use the HMS-10/HP connector with a wet interface ,
Hewlett-P ackard currently recommends using an index-matching oil (available as HP part
number 8500-4922). Oil or gel can be used on any connector where the cores have recessed
or the end faces have been damaged or worn, but this is a temporary solution at best. It
risks damaging the mating connector and incurring costly repair in the case of instrument
connectors .
Applying Index-Matching Compound
T o apply an index-matching compound, use the following procedure:
1. Apply index-matching compound to ber ends with a clean wooden toothpick, the wooden
end of a swab , or a syringe . Use as little index-matching compound as possible; the
index-matching compounds should be applied sparingly .
2. Coat the center of the ber end. Do not apply compound to the sleeve .
3. Use a clean or new applicator with every application.
F ollow these suggestions to ensure that as little dust as possible attaches itself to the ber ends:
Keep compound oil containers and applicators covered.
Keep swabs covered.
Make connections immediately after cleaning and applying compound.
Fiber-Optic Connections C-3