400G FR4 optical engines Working with Lumentum, POET expects to start sampling the 400G FR4 transmit optical engines with integrated drivers in the first half of 2023 and production by the second half of 2023. The 400G FR4 optical engines are architected as photonic chiplets and will be the industry’s first implementation of DMLs with flip-chip integration on an optical interposer at these data rates. With the small size and elegant design of POET’s optical engines, customers will have the flexibility to design 400G, 800G, and 1.6T pluggable transceivers using the same 400G FR4 chiplets.