optical fibre cables

[legacy]

I am a bit confused at the moment. The datasheet of my optical transreceiver says I need a 62.5um multimode cable with an LC connector, while the HBA needs a 62.5um Multimode SC Duplex Cable, so I need to buy a "LC to SC  62.5um patch".

What makes me confused is the offers I find on Amazon. Some say 62/125um (e.g. 3M P/N GCFA1CLM03-M), and it's ok, but some say 50um ... so 

[jc101]

For multimode fibre the older standard is 62.5/125 in size with more modern standards based on 50/125.  Does anything mention OM1, OM2, OM3 or OM4 as that defines the spec?

For 99% of kit a 50/125 will work fine in place of a 62.5/125 cable.  You will probably find way more 50/125 available these days.

For the various types see here https://en.wikipedia.org/wiki/Multi-mode_optical_fiber

I'd just get an OM3 or OM4 patch lead with the connectors you mention and all should be fine.

[legacy]

thanks for your hints 

Does anything mention OM1, OM2, OM3 or OM4 as that defines the spec?

unfortunately no. I have just checked and found that
- SC to LC are available with 62.5/125, rare but I can find some
- SC to SC are available with 50/125, haven't yet found one with the 62.5/125 spec

SC to SC is for a different project and needs to link two QLA2xxxF HBA.

I cannot see, in this case, what Qlogic recomends for the optical cable.

[jc101]

I’d just get the 50/125 regardless. The generic term multi-mode is basically just all 50/125 these days. 

[legacy]

Ok, let's try it 

[legacy]

OK, I have just purchased a couple of patch cables, 50/125. Let's see if they will work.

The manual of the HBA says only this

SC-style connector that supports non-OFC, multimode fibre optic cabling using 1x9 fibre optic transceiver module.

It's completely unclear if the transceiver uses a LED or a LASER, etc, and there are no other recommendations for the optic cabling.

Anyway I am 100% sure, this engine won't go faster than 10Gbs. It's not required, so OM1 "should" be OK.

[madires]

62.5µm multimode fiber is obsolete for quite a while. You can use 50µm MM if you don't need the maximum distance supported by the transceivers. Please see http://www.thefoa.org/tech/fib62-50.htm for some info about losses involved.

[legacy]

Yup, for my application, the cable's length is 50 meters.
So 50um is OK!