Nortel 1000 Manual page 36

36 Product description
Example: A maximum link length of a multi-mode fiber link with
bandwidth-length product of 500NHz km would be:
This multi-mode fiber link should not exceed 4.53 kilometers in length. A 3
dB safety margin should be allowed when engineering a multi-mode link
to compensate for additional attenuation as a result of core size variations
in fibers. The single-mode fiber core size varies between 8 and 9 microns
and the multi-mode fiber core size varies between 50 and 62.5 microns.
Fiber-optic interface specification
When planning a fiber-optic link, consider the transmit and receive
signal power and the signal attenuation of each component in the link to
determine total signal attenuation.
Table 2 "Fiber-optic transmit and receivesignal levels" (page 36)
transmit and receive signal power level at the signal source and the signal
destination. In the table, for simplicity, use FXNET for Fiber Superloop
Network and FXPEC for Fiber Peripheral Controller cards. The receive
circuit on the Electro-optical packlet must be able to detect a signal at a
level as low as –28 dBm.
Table 2
Fiber-optic transmit and receivesignal levels
Signal source
FXNET Card
FXPEC Card
Fiber-optic link loss characteristics
The fiber-optic link components add to the total end-to-end link signal
attenuation. The fiber-optic cable attenuation depends on the type of cable
selected. The manufacturer's data sheet provides necessary parameter
values, which must be considered when engineering the link. In addition,
the signal attenuation is also affected by the number of splices in the link
and the signal loss in the link terminating the fiber-optic connectors.
When measured at 1310 nanometers, the attenuation should not
exceed 10 dB.
–15 dBm
–15 dBm
Nortel Communication Server 1000
Fiber Remote IPE Fundamentals
NN43021-554 04.01 4 June 2010
Copyright © 2007-2010 Nortel Networks. All Rights Reserved.
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Transmitted power
Min Max
–8 dBm
–8 dBm
shows the
Received power
Min Max
–28 dBm –8 dBm
–28 dBm –8 dBm