From what I understand X and Y axis alignment is good and Z (depth) is a given. This is done by lithography and etches to produce mating points for alignment and then fixed in place by a solder reflow step. The solder reflow encompasses all active die in one step as understood by the associated patent. This makes it really fast to produce up the 400 optical engines at one time. Now testing each of this optical engines has been identified by way of a sacrificial waveguide that connects the send to the receive optical path. So setting up that process will be kind of the final steps to wafer level packaging and testing.
I know people want to understand what this all means but I view this as good news. If everything else has been proven to work as designed and they are in the final steps of automating the assembly then I think it is good news. Sometimes too much information can be worse than not enough in terms of providing confidence to the end result.
This is Suresh’s wheelhouse.