Less than one month ago, POET updated the shareholders with this:

All the design verifications and reliability testing of the optical engines is complete and all will be released to production this month.  Current module customers for these products include ADVA, Beijing FeiYunYi (BFYY) and Fibertop, along with others whose names have not yet been disclosed.

Peter Zhang, CEO and Chairman of the Board at YST said this:  

"We will continue to collaborate with POET on high-speed optical engines while supporting SPX to ramp current products to high volume production.”

(At this point we should probably stop questioning whether the technology works or not.)

https://poet-technologies.com/news/2023-oct-10.html