Energy Scavenging in Silicon Raman Amplifiers
  Continuous-wave Raman amplification in silicon waveguides with negative electrical power dissipation is reported. It is shown that a p-n junction can simultaneously achieve carrier sweep-out leading to net continuous-wave gain, and electrical power generation. The approach is also applicable to silicon Raman lasers and other third-order nonlinear optical devices. 
S. Fathpour, K. K. Tsia, and B. Jalali