All you need to do is read the detail in the article.

One statement stands out like a serious red thumb and huge problem compared to POET.

"Nainani estimates that this reuse could create gallium arsenide devices that would be 50 to 100 times more expensive than silicon circuits – still a big differential but much less than what exists today."

50 to 100 times more expensive ..... just from a cost perspective, this is not even on the same map as POET.

In addition, this appears to be geared towards the Solar Cell market, not SoC solutions and Optical / Electrical Monolithic integration.

Enjoy the ride,

ST