
53-16 Optical
of network components as illustrated, whereas the power reection peak at 40 km signies the Fresnel
re
ections
at th
e
b
er–air
in
terface
. A
er
th
e
b
er
en
d
no ba
ckscattering
is de
tected
an
d
th
e
tr
ace
dr
ops
to the receiver noise, which is usually dominated by the thermal noise of the electronic circuit.
Generally, the OTDR trace can be used to extract information about link faults, including ber mis-
alignment,
b
er
mi
smatch,
an
gular
fa
ults,
di
rt
on co
nnectors,
ma
crobends,
an
d/or
br
eaks
. e
se
fa
ults
are usually referred to as events on the OTDR trace. An OTDR device is a distributed ber sensing
instrument and can be eectively emplo ...