<s>
Subcarrier	B-Device
Multiplexing	I-Device
(	O
SCM	O
)	O
is	O
a	O
method	O
for	O
combining	O
(	O
multiplexing	B-Architecture
)	O
many	O
different	O
communications	O
signals	O
so	O
that	O
they	O
can	O
be	O
transmitted	O
along	O
a	O
single	O
optical	B-Architecture
fiber	I-Architecture
.	O
</s>
<s>
SCM	O
(	O
also	O
known	O
as	O
SCMA	O
,	O
SubCarrier	O
Multiple	O
Access	O
)	O
is	O
used	O
in	O
passive	B-Architecture
optical	I-Architecture
network	I-Architecture
(	O
PON	O
)	O
access	O
infrastructures	O
as	O
a	O
variant	O
of	O
wavelength	B-Architecture
division	I-Architecture
multiplexing	I-Architecture
(	O
WDM	O
)	O
.	O
</s>
<s>
The	O
operation	O
of	O
multiplexing	B-Architecture
and	O
demultiplexing	B-Architecture
the	O
single	O
subcarriers	O
is	O
carried	O
out	O
electronically	O
.	O
</s>
