C&B, the Marvel patent you linked provides a very clear indication of one of the fundamental advantages of POET. POET’s mux and demux are monolithic. They are formed within the waveguide fabric which is designed for very low loss in combination with athermal characteristics which limits thermal control needs to maintain accurate wavelength tuning. Low loss both in terms of transmission and coupling allows for lower power lasers that can be operated with higher efficiencies. Lower power lasers are of course lower in cost and provides energy saving as a prime goal of industry.

It is obvious that although assembly is at wafer scale the amount of assembly is considerably more extensive than POET’s design. Like POET, Marvel has moved beyond wire bonding with TSV’s which of course allows the assembly to operate at higher RF but I would argue that there is no way that this leads to the compact packaging that makes POET able to claim the semiconductorization of photonics. 

Marvel’s mux and demux are formed on glass or sapphire substrate which must be aligned to the corresponding silicon waveguides or fiber.