Designs should be completed soon actually... from the last blog  

"POET is on track to complete the design of the optical engines for FIT in 2024. There will be a period of about six months when FIT will sample the POET-equipped 800G optical transceiver modules to its customers. During the sampling phase, FIT customers may ask for design tweaks or customization, and such scenarios are built into the expected timeframe. POET anticipates FIT will place its first order for volume production in the second half of 2025. The 1.6T transceivers are expected to be sampled in late 2025 for production in late 2026"