I believe the VCSEL is contained within the interposer, is it not?

They have stated that the VCSEL was not a stand alone product, but they have not stated that they would not use it entirely. Page 3 of the April presentation states the optical engine contains "the bits of the transceiver that emit, detect and manage the photons, not including the electronics or housing..."

Just guessing, asking more than sayin'.

Until we get a better idea of what is inside the interposer, that's where I assume the VCSEL is...