<s>
Non-zero	B-Architecture
dispersion-shifted	I-Architecture
fiber	I-Architecture
(	O
NZDSF	O
)	O
,	O
specified	O
in	O
ITU-T	O
G.655	O
,	O
is	O
a	O
type	O
of	O
single-mode	B-Device
optical	I-Device
fiber	I-Device
which	O
was	O
designed	O
to	O
overcome	O
the	O
problems	O
of	O
dispersion-shifted	B-Device
fiber	I-Device
.	O
</s>
<s>
NZDSF	O
is	O
available	O
in	O
two	O
primary	O
flavours	O
:	O
NZD+	O
and	O
NZD-	O
,	O
which	O
differ	O
in	O
their	O
zero-dispersion	B-Device
wavelengths	I-Device
.	O
</s>
