Compensating For Launch And Receive Fibers; Types Of Compensation - Fluke OF-500-10 Technical Reference Handbook

OF-500 OptiFiber Certifying OTDR
Technical Reference Handbook
Fluke Networks recommends that you use launch and
receive fibers. You should also use launch/receive fiber
compensation to remove the effects of these fibers from
the OTDR measurements.
Avoid using hybrid patch cords to connect to the
cabling under test. Connect the launch and
receive fibers directly to the cabling under test,
using a launch fiber with the appropriate
connectors. This provides the best view of the
connectors at the ends of the cabling. Hybrid
launch fibers with various connector styles are
available from Fluke Networks.

Compensating for Launch and Receive Fibers

The launch fiber compensation function marks the end of
the launch fiber and the beginning of the receive fiber, if
used, on OTDR traces and labels these events in the event
table. It also removes these fibers' losses, lengths, and
attenuation coefficients from overall OTDR results. The
losses of the connections at the launch and receive fibers
are not removed from the results.
Launch compensation also provides a more accurate ORL
(optical return loss) measurement, provided that the
correct backscatter coefficient for the fiber under test is
entered on the Cable tab in SETUP.
3-4
Note
The compensation function does not affect ChannelMap
and real time trace results.

Types of Compensation

The tester offers three types of compensation:
•
Launch Only: Lets you compensate for a launch fiber.
•
Launch + Receive: Lets you compensate for a launch
fiber and a receive fiber.
•
Launch + Fiber + Receive: Lets you compensate for a
launch and receive fiber if you have forgotten to do
so before the receive fiber was taken to the other
end of the cabling.
Notes
Launch + Receive compensation usually provides
the most accurate measurements.
Avoid using Launch + Fiber + Receive
compensation on fibers longer than 8 km. Doing
so may degrade measurement accuracy.