Welcome LudLight, I believe the JV model diagram in the photos section still applies:

https://s3.amazonaws.com/s3.agoracom.com/public/photos/images/5892/large/JV_Model.jpg

My understanding is 400G OE's destined for outside of PRC are supplied (sold) to POET by SuperPhotonics.  POET then sells to whoever they want (ie NA Tier 1, etc) for integration into customer's own products, or perhaps as fully functional (POET?) transceivers.  Of course, alternate opinions welcome!

The important point being, POET has a means of mass production, something a NA Tier 1 customer would demand before entering into a business relationship....IMO