<s>
In	O
telecommunications	O
,	O
a	O
mode	B-Device
scrambler	I-Device
mode	B-Device
mixer	I-Device
is	O
a	O
device	O
for	O
inducing	O
mode	O
coupling	O
in	O
an	O
optical	B-Architecture
fiber	I-Architecture
,	O
or	O
a	O
device	O
that	O
,	O
itself	O
,	O
exhibits	O
a	O
uniform	O
output	O
intensity	O
profile	O
independent	O
of	O
the	O
input	O
mode	O
volume	O
or	O
modal	O
excitation	O
condition	O
.	O
</s>
<s>
Mode	B-Device
scramblers	I-Device
are	O
used	O
to	O
provide	O
a	O
modal	O
distribution	O
that	O
is	O
independent	O
of	O
the	O
optical	O
source	O
for	O
purposes	O
of	O
laboratory	O
,	O
manufacturing	O
,	O
or	O
field	O
measurements	O
or	O
tests	O
.	O
</s>
<s>
Mode	B-Device
scramblers	I-Device
are	O
primarily	O
used	O
to	O
improve	O
reproducibility	O
of	O
multimode	O
fiber	O
bandwidth	O
measurements	O
.	O
</s>
<s>
The	O
primary	O
purpose	O
of	O
a	O
mode	B-Device
scrambler	I-Device
is	O
to	O
create	O
a	O
uniform	O
,	O
overfilled	O
launch	O
condition	O
that	O
can	O
be	O
easily	O
reproduced	O
on	O
multiple	O
measurement	O
systems	O
,	O
so	O
that	O
measurement	O
systems	O
have	O
essentially	O
the	O
same	O
launch	O
conditions	O
and	O
can	O
measure	O
approximately	O
the	O
same	O
bandwidth	O
despite	O
having	O
different	O
laser	O
sources	O
.	O
</s>
<s>
The	O
output	O
modal	O
power	O
distribution	O
of	O
a	O
mode	B-Device
scrambler	I-Device
is	O
similar	O
to	O
the	O
surface-emitters	O
used	O
in	O
those	O
first	O
LAN	O
transmitters	O
,	O
but	O
this	O
was	O
fortuitous	O
coincidence	O
.	O
</s>
<s>
On	O
average	O
,	O
but	O
not	O
in	O
every	O
case	O
,	O
the	O
OFL	O
bandwidth	O
measured	O
using	O
a	O
mode	B-Device
scrambler	I-Device
is	O
lower	O
than	O
that	O
produced	O
by	O
excitation	O
of	O
a	O
partial	O
mode	O
volume	O
(	O
restricted	O
mode	O
launch	O
or	O
RML	O
)	O
,	O
such	O
as	O
occurs	O
with	O
directly	O
coupled	O
laser	O
diodes	O
.	O
</s>
<s>
There	O
are	O
two	O
common	O
types	O
of	O
mode	B-Device
scramblers	I-Device
:	O
the	O
"	O
Step-Graded-Step	O
"	O
(	O
S-G-S	O
)	O
and	O
the	O
"	O
step	O
index	O
with	O
bends	O
"	O
.	O
</s>
<s>
The	O
S-G-S	O
mode	B-Device
scrambler	I-Device
is	O
actually	O
an	O
assembly	O
,	O
a	O
fusion-spliced	O
concatenation	O
of	O
a	O
step-index	O
profile	O
,	O
a	O
graded-index	O
profile	O
and	O
another	O
step-index	O
profile	O
fiber	O
.	O
</s>
<s>
Unconventional	O
fiber	O
size	O
was	O
not	O
an	O
issue	O
,	O
as	O
they	O
were	O
developed	O
by	O
fiber	O
manufacturers	O
,	O
but	O
some	O
test	O
equipment	O
has	O
difficulty	O
complying	O
with	O
revised	O
qualification	O
standards	O
,	O
and	O
now	O
use	O
"	O
Step	O
Index	O
with	O
Bends	O
"	O
mode	B-Device
scramblers	I-Device
,	O
which	O
can	O
be	O
adjusted	O
to	O
purpose	O
.	O
</s>
<s>
Step	O
Index	O
with	O
Bend	O
mode	B-Device
scramblers	I-Device
are	O
created	O
simply	O
by	O
routing	O
a	O
specially	O
designed	O
step-index	O
multimode	O
fiber	O
through	O
a	O
series	O
of	O
small	O
radius	O
bends	O
,	O
or	O
by	O
compressing	O
fiber	O
against	O
surfaces	O
with	O
specific	O
roughness	O
.	O
</s>
<s>
A	O
mode	B-Device
scrambler	I-Device
can	O
be	O
characterized	O
and	O
qualified	O
by	O
measuring	O
its	O
near-field	O
and	O
far-field	O
distributions	O
,	O
as	O
well	O
as	O
by	O
measuring	O
one	O
of	O
these	O
distributions	O
while	O
restricting	O
the	O
other	O
.	O
</s>
<s>
Guidelines	O
for	O
constructing	O
a	O
mode	B-Device
scrambler	I-Device
and	O
qualifying	O
its	O
output	O
can	O
be	O
found	O
in	O
the	O
ANSI/TIA/EIA	O
-455-54	O
fiber	B-Architecture
optic	I-Architecture
test	O
procedure	O
(	O
FOTP	O
)	O
.	O
</s>
