<s>
An	O
optical	B-Protocol
module	I-Protocol
is	O
a	O
typically	O
hot-pluggable	O
optical	O
transceiver	O
used	O
in	O
high-bandwidth	O
data	O
communications	O
applications	O
.	O
</s>
<s>
Optical	B-Protocol
modules	I-Protocol
typically	O
have	O
an	O
electrical	O
interface	O
on	O
the	O
side	O
that	O
connects	O
to	O
the	O
inside	O
of	O
the	O
system	O
and	O
an	O
optical	O
interface	O
on	O
the	O
side	O
that	O
connects	O
to	O
the	O
outside	O
world	O
through	O
a	O
fiber	B-Architecture
optic	I-Architecture
cable	O
.	O
</s>
<s>
Optical	B-Protocol
modules	I-Protocol
can	O
either	O
plug	O
into	O
a	O
front	O
panel	O
socket	O
or	O
an	O
on-board	O
socket	O
.	O
</s>
<s>
Sometimes	O
the	O
optical	B-Protocol
module	I-Protocol
is	O
replaced	O
by	O
an	O
electrical	O
interface	O
module	O
that	O
implements	O
either	O
an	O
active	O
or	O
passive	O
electrical	O
connection	O
to	O
the	O
outside	O
world	O
.	O
</s>
<s>
A	O
large	O
industry	O
supports	O
the	O
manufacturing	O
and	O
use	O
of	O
optical	B-Protocol
modules	I-Protocol
.	O
</s>
<s>
There	O
have	O
been	O
multiple	O
variants	O
of	O
the	O
electrical	O
interface	O
of	O
optical	B-Protocol
modules	I-Protocol
that	O
have	O
been	O
used	O
over	O
the	O
years	O
.	O
</s>
<s>
The	O
earliest	O
forms	O
of	O
optical	B-Protocol
modules	I-Protocol
had	O
an	O
analog	O
NRZ	B-Protocol
electrical	O
interface	O
.	O
</s>
<s>
In	O
the	O
transmit	O
direction	O
,	O
the	O
optical	B-Protocol
module	I-Protocol
would	O
directly	O
drive	O
the	O
laser	O
or	O
LED	O
with	O
the	O
analog	O
signal	O
coming	O
from	O
the	O
front	O
system	O
card	O
.	O
</s>
<s>
The	O
Common	B-Protocol
Electrical	I-Protocol
Interface	I-Protocol
(	O
CEI	O
)	O
,	O
defined	O
by	O
the	O
Optical	O
Internetworking	O
Forum	O
(	O
OIF	O
)	O
served	O
as	O
the	O
central	O
defining	O
document	O
for	O
these	O
interfaces	O
.	O
</s>
<s>
In	O
order	O
to	O
save	O
power	O
within	O
the	O
module	O
,	O
optical	B-Protocol
modules	I-Protocol
have	O
been	O
made	O
that	O
used	O
the	O
digital	O
interface	O
definition	O
,	O
such	O
as	O
the	O
CEI	O
,	O
but	O
without	O
retiming	O
the	O
signals	O
within	O
the	O
module	O
.	O
</s>
<s>
The	O
Optical	O
Internetworking	O
Forum	O
in	O
2016	O
published	O
the	O
CFP2-ACO	B-Protocol
or	O
CFP2	O
-	O
Analog	O
Coherent	B-Protocol
Optics	I-Protocol
Module	I-Protocol
Interoperability	O
Agreement	O
(	O
IA	O
)	O
.	O
</s>
<s>
This	O
IA	O
supports	O
a	O
configuration	O
where	O
the	O
digital	B-Architecture
signal	I-Architecture
processor	I-Architecture
(	O
DSP	O
)	O
is	O
on	O
the	O
main	O
board	O
and	O
analog	O
optical	O
components	O
are	O
on	O
the	O
module	O
.	O
</s>
<s>
The	O
ACO	O
interface	O
can	O
be	O
used	O
in	O
coherent	O
optics	O
applications	O
when	O
the	O
link	O
delivers	O
a	O
flexible	O
amount	O
of	O
bandwidth	O
to	O
the	O
system	O
,	O
for	O
example	O
when	O
combined	O
with	O
FlexE	B-Protocol
.	O
</s>
<s>
The	O
typical	O
optical	O
modulation	O
that	O
are	O
used	O
include	O
Dual	B-General_Concept
Polarization	I-General_Concept
Quadrature	I-General_Concept
Phase	I-General_Concept
Shift	I-General_Concept
Keying	I-General_Concept
(	O
DP-QPSK	O
)	O
and	O
QAM-16	B-Device
.	O
</s>
<s>
Many	O
different	O
forms	O
of	O
optical	O
modulation	O
and	O
multiplexing	O
have	O
been	O
employed	O
in	O
optical	B-Protocol
modules	I-Protocol
.	O
</s>
<s>
The	O
most	O
common	O
modulation	O
technique	O
historically	O
has	O
been	O
on-off	B-Device
keying	I-Device
or	O
NRZ	B-Protocol
.	O
</s>
<s>
Pulse-amplitude	B-Device
modulation	I-Device
(	O
PAM-4	O
)	O
has	O
also	O
been	O
extensively	O
used	O
.	O
</s>
<s>
In	O
the	O
2010s	O
,	O
coherent	B-Protocol
optical	I-Protocol
modulation	I-Protocol
has	O
been	O
used	O
.	O
</s>
<s>
Techniques	O
include	O
Dual	B-General_Concept
Polarization	I-General_Concept
Quadrature	I-General_Concept
Phase	I-General_Concept
Shift	I-General_Concept
Keying	I-General_Concept
(	O
DP-QPSK	O
)	O
and	O
QAM-16	B-Device
.	O
</s>
<s>
Tunable	O
lasers	O
are	O
sometimes	O
used	O
to	O
allow	O
a	O
module	O
to	O
support	O
various	O
forms	O
of	O
network-based	O
optical	O
switching	O
such	O
as	O
needed	O
in	O
certain	O
cases	O
by	O
an	O
optical	B-Protocol
mesh	I-Protocol
networks	I-Protocol
or	O
a	O
Reconfigurable	O
optical	O
add-drop	O
multiplexer	O
(	O
ROADM	O
)	O
.	O
</s>
<s>
Different	O
optical	O
wavelengths	O
,	O
also	O
referred	O
to	O
as	O
lambdas	O
,	O
of	O
light	O
are	O
multiplexed	O
in	O
some	O
optical	B-Protocol
modules	I-Protocol
using	O
wavelength-division	B-Architecture
multiplexing	I-Architecture
(	O
WDM	O
)	O
.	O
</s>
<s>
Variants	O
include	O
Coarse	B-Architecture
WDM	I-Architecture
(	O
CWDM	O
)	O
,	O
Dense	O
WDM	O
(	O
DWDM	O
)	O
.	O
</s>
<s>
Optical	B-Protocol
modules	I-Protocol
have	O
a	O
series	O
of	O
components	O
inside	O
,	O
some	O
of	O
which	O
have	O
received	O
attention	O
from	O
standards	O
development	O
organizations	O
.	O
</s>
<s>
Particularly	O
in	O
the	O
long-reach	O
module	O
market	O
,	O
in-module	O
Forward	B-Error_Name
Error	I-Error_Name
Correction	I-Error_Name
(	O
FEC	O
)	O
has	O
been	O
included	O
.	O
</s>
<s>
The	O
OIF	O
has	O
created	O
interoperability	O
agreements	O
to	O
create	O
multi-vendor	O
interoperability	O
for	O
the	O
tunable	O
lasers	O
that	O
are	O
sometimes	O
used	O
in	O
optical	B-Protocol
modules	I-Protocol
.	O
</s>
<s>
The	O
Transmit	O
Optical	O
Sub-Assembly	O
or	O
TOSA	O
in	O
the	O
optical	B-Protocol
module	I-Protocol
converts	O
electrical	O
signals	O
into	O
optical	O
signals	O
for	O
optical	O
transmitters	O
.	O
</s>
<s>
Sometimes	O
the	O
optical	B-Protocol
module	I-Protocol
is	O
replaced	O
by	O
an	O
electrical	O
interface	O
module	O
that	O
implements	O
either	O
an	O
active	O
or	O
passive	O
electrical	O
connection	O
to	O
the	O
outside	O
world	O
.	O
</s>
<s>
Many	O
Multi-source	O
agreements	O
(	O
MSAs	O
)	O
have	O
come	O
and	O
gone	O
over	O
the	O
years	O
in	O
the	O
optical	B-Protocol
module	I-Protocol
industry	O
.	O
</s>
<s>
The	O
Small	B-Protocol
form-factor	I-Protocol
pluggable	I-Protocol
transceiver	I-Protocol
(	O
SFP	O
)	O
MSA	O
has	O
specified	O
many	O
optical	B-Protocol
module	I-Protocol
form	O
factors	O
over	O
the	O
years	O
.	O
</s>
<s>
The	O
C	B-Protocol
form-factor	I-Protocol
pluggable	I-Protocol
(	O
CFP	O
)	O
is	O
an	O
MSA	O
among	O
competing	O
manufacturers	O
for	O
a	O
common	O
form-factor	O
for	O
the	O
transmission	O
of	O
high-speed	O
digital	O
signals	O
.	O
</s>
<s>
The	O
letter	O
"	O
C	O
"	O
in	O
the	O
name	O
stands	O
for	O
the	O
Latin	O
letter	O
C	O
used	O
to	O
express	O
the	O
number	O
100	O
(	O
centum	O
)	O
,	O
since	O
the	O
standard	O
was	O
primarily	O
developed	O
for	O
100	B-Protocol
Gigabit	I-Protocol
Ethernet	I-Protocol
systems	O
.	O
</s>
<s>
The	O
XENPAK	O
MSA	O
was	O
publicly	O
announced	O
on	O
March	O
12	O
,	O
2001	O
and	O
the	O
first	O
revision	O
of	O
the	O
document	O
was	O
publicly	O
released	O
on	O
May	O
7	O
,	O
2001	O
and	O
was	O
a	O
multisource	O
agreement	O
(	O
MSA	O
)	O
,	O
instigated	O
by	O
Agilent	O
Technologies	O
and	O
Agere	O
Systems	O
,	O
that	O
defines	O
a	O
fiber-optic	B-Architecture
or	O
wired	O
transceiver	O
module	O
which	O
conforms	O
to	O
the	O
10	O
Gigabit	O
Ethernet	O
(	O
10GbE	O
)	O
standard	O
of	O
the	O
Institute	O
of	O
Electrical	O
and	O
Electronics	O
Engineers	O
(	O
IEEE	O
)	O
802.3	O
working	O
group	O
.	O
</s>
<s>
Soon	O
after	O
the	O
standard	O
was	O
introduced	O
in	O
2001	O
,	O
two	O
related	O
standards	O
emerged	O
:	O
XPAK	O
and	O
the	O
X2	B-Device
.	O
</s>
<s>
These	O
two	O
standards	O
had	O
the	O
same	O
electrical	O
interface	O
as	O
XENPAK	O
(	O
known	O
as	O
XAUI	B-Protocol
)	O
but	O
different	O
mechanical	O
properties	O
.	O
</s>
<s>
The	O
XFP	O
(	O
10	O
Gigabit	O
Small	O
Form	O
Factor	O
Pluggable	O
)	O
is	O
a	O
standard	O
for	O
transceivers	O
for	O
high-speed	O
computer	B-Architecture
network	I-Architecture
and	O
telecommunication	O
links	O
that	O
use	O
optical	B-Architecture
fiber	I-Architecture
.	O
</s>
<s>
XFP	O
is	O
a	O
slightly	O
larger	O
form	O
factor	O
than	O
the	O
popular	O
small	B-Protocol
form-factor	I-Protocol
pluggable	I-Protocol
transceiver	I-Protocol
,	O
SFP	O
and	O
SFP+	B-Protocol
.	O
</s>
<s>
Multiple	O
standards	O
have	O
used	O
optical	B-Protocol
modules	I-Protocol
.	O
</s>
<s>
InfiniBand	B-Architecture
(	O
abbreviated	O
IB	O
)	O
is	O
a	O
computer-networking	O
communications	O
standard	O
used	O
in	O
high-performance	O
computing	O
that	O
features	O
very	O
high	O
throughput	O
and	O
very	O
low	O
latency	O
.	O
</s>
<s>
InfiniBand	B-Architecture
is	O
also	O
utilized	O
as	O
either	O
a	O
direct	O
,	O
or	O
switched	O
interconnect	O
between	O
servers	O
and	O
storage	O
systems	O
,	O
as	O
well	O
as	O
an	O
interconnect	O
between	O
storage	O
systems	O
.	O
</s>
<s>
Infiniband	B-Architecture
uses	O
optical	B-Protocol
modules	I-Protocol
extensively	O
.	O
</s>
<s>
Fibre	B-Architecture
Channel	I-Architecture
(	O
FC	O
)	O
is	O
a	O
high-speed	O
network	O
technology	O
(	O
commonly	O
running	O
at	O
1	O
,	O
2	O
,	O
4	O
,	O
8	O
,	O
16	O
,	O
32	O
,	O
and	O
128	O
gigabit	O
per	O
second	O
rates	O
)	O
primarily	O
used	O
to	O
connect	O
computer	O
data	O
storage	O
to	O
servers	O
.	O
</s>
<s>
Fibre	B-Architecture
Channel	I-Architecture
is	O
mainly	O
used	O
in	O
storage	O
area	O
networks	O
(	O
SAN	O
)	O
in	O
commercial	O
data	O
centers	O
.	O
</s>
<s>
Fibre	B-Architecture
Channel	I-Architecture
networks	O
form	O
a	O
switched	B-Architecture
fabric	I-Architecture
because	O
they	O
operate	O
in	O
unison	O
as	O
one	O
big	O
switch	O
.	O
</s>
<s>
Fibre	B-Architecture
Channel	I-Architecture
typically	O
runs	O
on	O
optical	B-Architecture
fiber	I-Architecture
cables	O
within	O
and	O
between	O
data	O
centers	O
.	O
</s>
<s>
Fibre	B-Architecture
Channel	I-Architecture
uses	O
optical	B-Protocol
modules	I-Protocol
extensively	O
.	O
</s>
<s>
Ethernet	O
is	O
a	O
family	O
of	O
computer	B-Architecture
networking	I-Architecture
technologies	O
commonly	O
used	O
in	O
local	O
area	O
networks	O
(	O
LAN	O
)	O
,	O
metropolitan	O
area	O
networks	O
(	O
MAN	O
)	O
and	O
wide	O
area	O
networks	O
(	O
WAN	O
)	O
.	O
</s>
<s>
Ethernet	O
uses	O
optical	B-Protocol
modules	I-Protocol
extensively	O
in	O
its	O
higher	O
rate	O
interfaces	O
.	O
</s>
<s>
Representative	O
interfaces	O
that	O
are	O
commonly	O
implemented	O
in	O
optical	B-Protocol
modules	I-Protocol
include	O
100GBASE-SR4	O
,	O
100GBASE-LR4	O
and	O
100GBASE-ER4	O
.	O
</s>
<s>
The	O
main	O
trade	O
show	O
for	O
the	O
large	O
optical	B-Protocol
module	I-Protocol
industry	O
is	O
the	O
Optical	B-Architecture
Fiber	I-Architecture
Conference	O
(	O
OFC	O
)	O
,	O
that	O
is	O
held	O
annually	O
in	O
southern	O
California	O
.	O
</s>
