<s>
In	O
multimode	O
fiber	B-Architecture
optics	I-Architecture
,	O
mandrel	B-Device
wrapping	I-Device
is	O
a	O
technique	O
used	O
to	O
preferentially	O
attenuate	O
high-order	O
mode	O
power	O
of	O
a	O
propagating	O
optical	O
signal	O
.	O
</s>
<s>
A	O
cylindrical	B-Device
rod	I-Device
wrap	I-Device
consists	O
of	O
a	O
specified	O
number	O
turns	O
of	O
fiber	O
on	O
a	O
mandrel	O
of	O
specified	O
size	O
,	O
depending	O
on	O
the	O
fibre	O
characteristics	O
and	O
the	O
desired	O
modal	O
distribution	O
.	O
</s>
<s>
If	O
the	O
launch	O
fibre	O
is	O
fully	O
filled	O
ahead	O
of	O
the	O
mandrel	B-Device
wrap	I-Device
,	O
the	O
higher-order	O
modes	O
will	O
be	O
stripped	O
off	O
,	O
leaving	O
only	O
lower-order	O
modes	O
.	O
</s>
<s>
In	O
multimode	O
fibre	O
,	O
mandrel	B-Device
wrapping	I-Device
is	O
used	O
to	O
eliminate	O
the	O
effect	O
of	O
"	O
transient	O
loss	O
"	O
,	O
the	O
tendency	O
of	O
high	O
order	O
modes	O
to	O
experience	O
higher	O
loss	O
than	O
lower	O
order	O
modes	O
.	O
</s>
<s>
In	O
single	O
mode	O
optical	B-Architecture
fibre	I-Architecture
measurements	O
,	O
it	O
is	O
used	O
to	O
enforce	O
true	O
single	O
mode	O
propagation	O
at	O
wavelengths	O
near	O
or	O
below	O
the	O
theoretical	O
cutoff	O
wavelength	O
,	O
at	O
which	O
substantial	O
power	O
can	O
exist	O
in	O
a	O
higher	O
order	O
mode	O
group	O
.	O
</s>
<s>
Ultimately	O
,	O
the	O
effect	O
of	O
mandrel	B-Device
wrapping	I-Device
on	O
optical	O
measurements	O
depends	O
on	O
the	O
propagating	O
mode	O
power	O
distribution	O
.	O
</s>
<s>
The	O
effect	O
of	O
physically	O
bending	O
an	O
optical	B-Architecture
fibre	I-Architecture
around	O
a	O
cylindrical	O
form	O
is	O
to	O
slightly	O
modify	O
the	O
effective	O
refractive	O
index	O
in	O
the	O
curved	O
region	O
,	O
which	O
locally	O
reduces	O
the	O
effective	O
mode	O
volume	O
of	O
the	O
fibre	O
.	O
</s>
<s>
The	O
practical	O
effect	O
of	O
mandrel	B-Device
wrapping	I-Device
is	O
to	O
attenuate	O
optical	O
power	O
propagating	O
in	O
the	O
highest	O
order	O
modes	O
.	O
</s>
