My understanding is that 400Gs overall is a few years away. POET is entering at 100Gs, ... BUT... what is highly significant is that POET can leapfrog others who are researching to development 400Gs. And that is what will allow POET to come in at 400Gs as a leader.  This was in a slide presentation by Suresh a couple of presentations ago.  Remember, the 'disruptive' capability of what POET has is speed agnostic and, of course, the packaging is smaller allowing for a lower cost. oz4m2, fairchijisback, and some others here may want to chime in as I only can offer a generalization.

I just noticed inthisthinrain quoted Suresh as I was posting this, so it would be good for you to refer to that post and hear it straight from the horse's mouth.

Monolithic