<s>
The	O
optical	B-Protocol
power	I-Protocol
budget	I-Protocol
in	O
a	O
fiber-optic	B-Application
communication	I-Application
link	O
is	O
the	O
allocation	O
of	O
available	O
optical	O
power	O
(	O
launched	O
into	O
a	O
given	O
fiber	B-Architecture
by	O
a	O
given	O
source	O
)	O
among	O
various	O
loss-producing	O
mechanisms	O
such	O
as	O
launch	O
coupling	O
loss	O
,	O
fiber	B-Architecture
attenuation	O
,	O
splice	O
losses	O
,	O
and	O
connector	B-Device
losses	O
,	O
in	O
order	O
to	O
ensure	O
that	O
adequate	O
signal	O
strength	O
(	O
optical	O
power	O
)	O
is	O
available	O
at	O
the	O
receiver	O
.	O
</s>
<s>
In	O
optical	B-Protocol
power	I-Protocol
budget	I-Protocol
attenuation	O
is	O
specified	O
in	O
decibel	O
(	O
dB	O
)	O
and	O
optical	O
power	O
in	O
dBm	B-General_Concept
.	O
</s>
<s>
The	O
amount	O
of	O
optical	O
power	O
launched	O
into	O
a	O
given	O
fiber	B-Architecture
by	O
a	O
given	O
transmitter	O
depends	O
on	O
the	O
nature	O
of	O
its	O
active	O
optical	O
source	O
(	O
LED	O
or	O
laser	O
diode	O
)	O
and	O
the	O
type	O
of	O
fiber	B-Architecture
,	O
including	O
such	O
parameters	O
as	O
core	B-Device
diameter	I-Device
and	O
numerical	O
aperture	O
.	O
</s>
<s>
Manufacturers	O
sometimes	O
specify	O
an	O
optical	B-Protocol
power	I-Protocol
budget	I-Protocol
only	O
for	O
a	O
fiber	B-Architecture
that	O
is	O
optimum	O
for	O
their	O
equipment	O
—	O
or	O
specify	O
only	O
that	O
their	O
equipment	O
will	O
operate	O
over	O
a	O
given	O
distance	O
,	O
without	O
mentioning	O
the	O
fiber	B-Architecture
characteristics	O
.	O
</s>
<s>
The	O
user	O
must	O
first	O
ascertain	O
,	O
from	O
the	O
manufacturer	O
or	O
by	O
testing	O
,	O
the	O
transmission	O
losses	O
for	O
the	O
type	O
of	O
fiber	B-Architecture
to	O
be	O
used	O
,	O
and	O
the	O
required	O
signal	O
strength	O
for	O
a	O
given	O
level	O
of	O
performance	O
.	O
</s>
<s>
Passive	B-Architecture
optical	I-Architecture
networks	I-Architecture
use	O
optical	O
splitters	O
to	O
divide	O
the	O
downstream	O
signal	O
into	O
up	O
to	O
32	O
streams	O
,	O
most	O
often	O
a	O
power	O
of	O
two	O
.	O
</s>
