Further to this post, I found today where it is established fact that the $250M by 2024-25 is the baseline.
And according to Rajgarhia, these figures don't actually take into account POET's activities outside of the joint venture. The company also hopes to expand into other markets including artificial intelligence and 5G telecommunications. Indeed, Sanan Optoelectronics currently has a huge presence in 5G, so this market could be a natural extension for POET and the joint venture.
https://compoundsemiconductor.net/article/112112/POET_Technologies_Delivering_Scale_To_Datacoms