The optical switch got highlighted in March in Nature Photonics. See the attached report. I guess this is interesting after all. I should also mention that this research is being worked on in other material systems of which Si is the most important. Notomi's group(http://www.brl.ntt.co.jp/people/notomi/) at NTT basic research lab has demonstrated some nice switching with ion implanted Si. Depleting the carrier fast is the name of the game.
