To clarify, these product announcements from Mitsubishi are for components of an optical engine, they will be incorporated into POET optical engines.  ie they go into POET not POET going into them.

In this case, the 200G lasers will be incorporated into POET's 800G/1.6T (3.2T?) transmit engines and the more recent announcement of 200G photodiodes will be incorporated into POET's 800G/1.6T receive engines.  My guess, this is what they are developing as we speak.