<s>
An	O
optical	B-Protocol
communications	I-Protocol
repeater	I-Protocol
is	O
used	O
in	O
a	O
fiber-optic	B-Application
communications	I-Application
system	O
to	O
regenerate	O
an	O
optical	O
signal	O
.	O
</s>
<s>
Some	O
repeaters	O
also	O
correct	O
for	O
distortion	B-Device
of	O
the	O
optical	O
signal	O
by	O
converting	O
it	O
to	O
an	O
electrical	O
signal	O
,	O
processing	O
that	O
electrical	O
signal	O
and	O
then	O
retransmitting	O
an	O
optical	O
signal	O
.	O
</s>
<s>
:	O
Mamyshev	B-Protocol
2R	I-Protocol
regenerator	I-Protocol
.	O
</s>
<s>
Cost	O
efficiency	O
has	O
led	O
to	O
OEO	O
repeaters	O
being	O
largely	O
replaced	O
in	O
long-haul	O
systems	O
by	O
optical	O
amplifiers	O
since	O
one	O
(	O
broadband	B-Algorithm
)	O
amplifier	O
can	O
be	O
used	O
for	O
many	O
wavelengths	O
in	O
a	O
Wavelength	B-Architecture
Division	I-Architecture
Multiplexing	I-Architecture
(	O
WDM	O
)	O
system	O
.	O
</s>
<s>
Electrical	O
repeaters	O
are	O
also	O
limited	O
in	O
bandwidth	B-Algorithm
and	O
modulation	O
format	O
.	O
</s>
<s>
An	O
amplifier	O
does	O
not	O
provide	O
the	O
regeneration	O
ability	O
of	O
a	O
repeater	O
,	O
but	O
loss	O
,	O
rather	O
than	O
distortion	B-Device
is	O
generally	O
the	O
limiting	O
factor	O
in	O
the	O
design	O
of	O
an	O
optical	O
communications	O
system	O
.	O
</s>
