Not to fan the flames of rumour, but this Cisco blog post is very interesting (dated July 2019) as it alludes to all of the challenges in Optics that Poet is systematically addressing with their OI

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

Cost:

"The result is that as the bit rate increases, pluggable optics represents a larger fraction of the total hardware cost"

Fabrication

"As optics speeds increase, so does the complexity in the design and manufacturing of pluggable optics."

Test/Assembly

"The optics industry still largely relies on a “discrete” set of components with very cumbersome testing and assembly processes. If we contrast that with the semiconductor industry – where extremely complex functions are integrated into silicon (ASICs) using highly automated processes that have very little to no reliance on human interaction – we see an opportunity to leverage these processes in the processing of “photonic signals” rather than “electrical signals” that semiconductor processes naturally manage. The promise of silicon photonics is to leverage the semiconductor industry processes to more fully automate the process of optics manufacturing"