Just as a followup to my previous reply regarding the mitigating factors in the cost of switching to GaAs from Si CMOS, I'm posting a link to the whitepaper OPEL produced.
Longs are farmiliar with this document, but AFAIK it hasn't been up on Agora yet. It provides some support for what I wrote and contains other technical data also
Enjoy!
http://www.odisinc.com/documents/WhitePaper28Mar11_Si_Photonics_vs_POET.pdf