How to get 1 or 2Km of optical fiber?

Lloyd Brown lloyd_brown at byu.edu
Mon Mar 18 09:47:43 MDT 2013


When working with fiber lengths, you *always* want to consult the
specifications of your optics modules.

For example, we use a lot of hardware from Force10 Neworks here (They've
been bought out by Dell, which is advantageous for us, for other
reasons).  My spec sheet for their 10GbE SFP+ optics modules says 300
meters on multi-mode using 850nm wavelength (10GBASE-SR), as long as
it's OM3 or OM4 spec, but I don't have lengths for OM1 or OM2 MMF (I
vaguely recall it was 150m, but I don't know for sure).  For the
10GBASE-LR (1310nm), you use single-mode for up to 10km.  For the
10GBASE-ER (1550nm) you use single-mode for up to 40km.

In general, you can use 850nm on multi-mode, and 1310nm and 1550nm on
single-mode.  There are a few applications (eg. 10GBASE-ESR), which pair
1310nm with multi-mode, but they're rare and will probably be more
expensive than you want to pay.

And of course everything changes when you're talking about faster
speeds, eg. 40GBASE or 100GBASE.

TLDR: At the lengths you're talking about, it's going to depend on what
the optics vendor will support.

Lloyd Brown
Systems Administrator
Fulton Supercomputing Lab
Brigham Young University
http://marylou.byu.edu

On 03/18/2013 09:38 AM, Michael Torrie wrote:
> On 03/18/2013 08:24 AM, David Landry wrote:
>> Unjacketed fiber is commonly sold in spools between 10km and 50km. That
>> would require you to jacket them and connectorize them yourself. I also ran
>> across jacketed, pre-terminated spools here:
>> http://www.lanshack.com/Outdoor-Pre-Terminated-Assembly-C51.aspx
> 
> So does anyone know what fiber one would use for a short link, say 250
> meters or so?  Multimode or singlemode?  Singlemode is slightly cheaper
> and has no significant bandwidth cap on it.  But I can't get a clear
> answer on the interwebs as to which kind is best to use for what.
> 
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