Third Party OLT Optics

Mon Jan 6 21:33:27 UTC 2020

On 1/6/20 11:05 AM, Mike Hammett wrote:
> What is the vendor-lock scene like in the world of OLT optics? Is it as 
> bad as Ethernet optics? If it exists, is there actually a good reason 
> for it (other than money)?

My experience has been that it's arguably worse.  Some sort of vendor 
lock is downright common often with no way to override it.  Of course, 
you can always re-code the optics, but bleh.

The claims usually are that GPON (and PON in general) is more sensitive 
to timing and DDM characteristics of the optic than AE (which is, to a 
degree, true) and that OLT optics launch much higher power than typical 
AE optics (also true) and that therefore it's required that you use 1st 
party optics to maintain FDA laser compliance (which is, afaik, BS).

The way I know most of this (aside from the DDM interface specifics, 
potentially) is BS is that the same vendor(s) generally have 
surprisingly little to say about the passive optics.

> I'm sure I'll get people saying that for something so important, one 
> should only deploy first-party optics, regardless of the cost. Zhone's 
> pricing isn't bad at all....    but if there's effectively no 
> difference, then you might as well buy the cheaper one.

My solution has been to grill my preferred OLT vendor on their 1st party 
optic cost.  I've generally been able to get them down to the point 
where, while still notably more expensive than white-box offerings, it's 
not patently outrageous, and then I don't get support hassles which is 
worth at least something (even if it's largely artificial) on a port 
with 32+ potential users on it if I do have an apparent issue that may 
be related to the optics.

My one complaint with fs.com optics has also been somewhat more variable 
launch power from unit to unit.  Though they are always within spec, 
they seem to vary a bit more than with bigger name modules especially 
within a lot.  That does matter a bit more with PON optics than with AE, 
so that is one thing to consider, too, though it's a minor complaint 
again since everything is always within spec.
-- 
Brandon Martin