Sorry to dwell on this subject, but i found another article i thought some on this board might find interesting.
Optoelectronic microprocessors built using existing chip manufacturing
http://www.newslocker.com/en-us/news/sci-tech/optoelectronic-microprocessors-built-using-existing-chip-manufacturing/view/
If you follow the link at the bottom of the article:
Selling chip makers on optical computing
http://phys.org/news/2009-11-chip-makers-optical.html
It's interesting to note they have been working on this since 2009.
Cheers