HP 83481A, User Manual, Page: 27 / 98

The Instrument at a Glance
Lightwave Connector Care
Return loss is another important factor . It is a measure of reection: the less
reection the better (the larger the return loss , the smaller the reection).
The best physically contacting connectors have return losses better than
40 dB , although 20 to 30 dB is common.
Causes of connector loss and reections include core misalignment,
dierences in the numerical aperture of two bers , spacing and air gaps ,
reections caused by damaged, worn, or loose ber ends , and the improper
use and removal of index matching compounds .
A chieving the best possible connection, where the ber end faces are ush
(no air gap) and properly aligned, depends on two things:
1. The type of connector
2. Using the proper cleaning and connecting techniques . If the connection is
lossy or reective , light will not make a smooth transition. If the transition
is not smooth or the connection is not repeatable , measurement data will
be less accurate . F or this reason, lightwave connections can make a critical
dierence in optical measurement systems .
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