Thanks Rogue, as the saying goes, cost is king!  

By using DR8 it says something about their ability to package everything in one engine.  POET's 800G solution will only need 4 fibres, while DR8 requires 16 fibres to do the same work.  Why? no integrated mux/demux capability.  As a data centre operator wouldn't it make sense to cut your fibre count by 4x to achieve same performance.  Alternatively, the same 16 fibre count could get to 3.2T using POET's OE.  I suspect this isn't the only advantage POET has over the "competition"!