# SMF-28 attenuation vs wavelength

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Hi,

I'm looking for the fibre SMF-28 attenuation vs wavelength in the range
1550 - 1630 nm.
I just can find the typical 0.2 dB/km.

Regards,

Stephane.

Re: SMF-28 attenuation vs wavelength

And your problem with that is what, precisely?

SMF-28 is a bit old-school. Not sure where to dig up a product data
sheet for it at this date. Ah, here's a blast from 2002 just for that.
http://ece466.groups.et.byu.net/notes/smf28.pdf

for the worst case, take the non-premium fiber number at 1550 and apply
the attenuation .vs. wavelength adjustment to get 0.27 dB/km (and look
at the typical fiber graph to extrapolate downward towards 1600)

SMF-28e+ has a currently available datasheet, which pretty much says you
probably have an acceptable number already. The water-peak reduction is
at shorter wavelengths than you are asking about, so it probably has
little effect .vs. old SMF-28, if that is what you have.

http://www.corning.com/WorkArea/showcontent.aspx?id=57655

1550 - 0.19-0.20 dB/km 1525-1575 delta 0.03 dB/km
1625 - 0.20-0.23 dB/km

Those are maximums, for design purposes - a link designed with those
numbers and correctly installed should function. Actual attenuation
could be less without violating specs.

If you have a need for "actual" rather than "maximum" attenuation,
you'll have to measure it, and reduce all points of measurement error as
much as possible if you feel a need for greater precision. That will
tell you what the piece of cable you are measuring will do - it may not
generalize to other cables well.

If you have a need for greater reliability, assume 0.25 dB/km and build
in some margin.

If you have some other need, please explain it more completely, and you