I'm surprised that they haven't cracked the full-silicon problem yet. We were looking at silicon quantum cascade lasers as a replacement for 3/5 QCLs back in co

I'm surprised that they haven't cracked the full-silicon problem yet. We were looking at silicon quantum cascade lasers as a replacement for 3/5 QCLs back in college as an undergraduate project way back in 2006, and the lab PI seemed to think that the problem would be solved in two-three years. Unfortunately I had rent to pay, so I had to leave the project and start writing software for a living. I should probably drop my old professor a line and ask her what the happened after I left...