LX sfp minimum range

Thu Jan 26 23:19:38 UTC 2012

On Thu, Jan 26, 2012 at 10:48:05PM +0000, Gary Buhrmaster wrote:
> On Thu, Jan 26, 2012 at 13:47, David Storandt <dstorandt at teljet.com> wrote:
> > You can put a 3dB or 5dB optical pad on the link if the receiver can't
> > handle zero-distance optical power.
> 
> As I recall, the problem may not only be the power
> (which can cause receiver saturation), but issue that
> fibre paths shorter than (around) 2-10m do not properly
> condition the light(*), which can result in some issues
> at the receiver.
> 
> Gary
> 
> (*) My memory says modal distribution issues.
>     While 'single mode' fibre only supports one
>     mode of transmission, it takes a short distance
>     for the fibre to really be single mode.  You can
>     use a mode filter to address the problem, or just
>     use fibres that are at least a few meters.

When optics started to become scarce at various times, I've done a
number of back-to-back connections using SM fiber and have had zero
issues. I wouldn't even worry about it. Remember, many carriers won't
even touch MM and they aren't chronically reporting issues or going to
lengths to work around them.

-Wayne

---
Wayne Bouchard
web at typo.org
Network Dude
http://www.typo.org/~web/