Interestingly the latest OSFP-XP specifications draft was just issued yesterday (just in time for OFC?) The OFSP MESA is being led by CISCO/Arista. Pretty exciting stuff for sure. Kind of adds merit to what many of us have believed for a while now. POET is engaged with CISCO...IMO. 

Dry reading but here it is: OSFP-XD_Specification_Draft_Rev0_9.pdf (osfpmsa.org) 

Re the one chip optical engine. 

If the TX and RX don't need to be combined to reduce the footprint for specific space limitation requirements then why bother? Keeping them separate does have some benefits. The big one I think is that it limits the mask sets required. One mask set for 400G TX engines and one mask set for 800G RX engines. 

Also isolating thermal control requirements has benefits as well. 

It will be interesting to see what 200G lambda brings and lets hope that POET does not have to wait for industry to establish those standards. If POET is to leapfrog industry they will have to have a good understanding of where they need to land.