Guys the way to look at this is as follows:

As optics speeds increase, so does the complexity in the design and manufacturing of pluggable optics. Beginning with 100G speeds, this has caused pluggable optics to lag behind the availability of router/switch ASICs, and generally delaying network migration to higher speeds to meet the higher bandwidth demand.

So what POET is providing is the 400G optical engine associated with the pluggable module to support the port density that is becoming available.  

Today, 100G pluggable optics are deployed in large scale data center applications, with plans for 400G migration as router/switch ports now support 400G.

Everyone has been waiting for the optics to catch up as the move to 400G was delayed playing right into POET’s hands. When POET is ready to announce a successful optical engine based on low loss and small footprint at low cost well there will be a lot of people lining up for it.  

https://blogs.cisco.com/sp/optics-in-the-data-center-powering-ever-increasing-capacity-demands