What is the difference between OM2 & OM3 fiber optic cables

[itguypeon]

I have a couple of questions concerning OM3 fiber optics. As i was searching for a vender to provide the cables needed for a job i have ran into OM2 & OM3 fiber patch cords. Besides the color difference, is OM3 the new revolutionary cable type being used now and days? The specs i have seen between the 2 are quite similar, both are 50 microns. Are these specs correct on this website? 10gfiber.com 10GB Gigabit OM3 Fiber Optic Ethernet Cables

[m25man]

Everything you need to know is everywhere on the web Multi-mode optical fiber - Wikipedia, the free encyclopedia

 

Very very simply Multimode for short reach solutions SingleMode for Longreach.

The size 50/125 62.5/125 refers to the core/cladding size so you are correct in the assumption that OM2 and OM3 share the same physical characteristics.

The purity of the fibre means that the on/off switching rates of the lasers can be pushed to the 10Gb threshold (try looking at the stars through dirty spectacles).

 

In the same way that a copper cable looses voltage over longer distances, optical loss is what is important in fibre connections. OM4 is already here and being used in some environments.

 

The thing that is often overlooked is that most of us have Fibre installed for relatively short runs often just where copper would be just overstretched or has to be routed alongside 3 phase or other potential induction risks.

Quite often your existing OM2 50/125 links can be more than capable of carrying a 10GBe signal so dont be brow beaten by your suppliers into ripping everything out before having it properly tested.

A decent cabling company will have a DTX with 10GBe test capabilities nowadays and it takes a few minutes to pass/fail a fibre for 10GBe but generally 10GBe will run over OM2 for limited distances using the right modules.

This document has some useful data http://www.techdata.com/(S(gec5go45l3e3a2ecpbinz055))/netgear/files/NETGEAR-Whitepaper-10_Things_10_Gigabit-v1.pdf

Edited June 26, 2012 by m25man

[twin--turbo]

And watch out they don't put single mode in by mistake, after discussing with a building contractor (and the sub contractor) a 300M link between 2 buildings and the requirement that it only realy needed to shovel 1Gb, it was decided they should put in Multimode instead of their proposed Single Mode.

 

When the I.T. contractor tried to get it working they could not, it transpired it was Single mode and the cost of the SFP modules went from ~£120 to over £600 (and there is one at each end!)

 

Rob