Ultra-low power generation of twin photons in a compact silicon ring   resonator
  We demonstrate efficient generation of correlated photon pairs by spontaneous four wave mixing in a 5 \mu m radius silicon ring resonator in the telecom band around 1550 nm. By optically pumping our device with a 200 \mu W continuous wave laser, we obtain a pair generation rate of 0.2 MHz and demonstrate photon time correlations with a coincidence-to-accidental ratio as high as 250. The results are in good agreement with theoretical predictions and show the potential of silicon micro-ring resonators as room temperature sources for integrated quantum optics applications. 
Stefano Azzini, Davide Grassani, Michael J. Strain, Marc Sorel, L. G.   Helt, J. E. Sipe, Marco Liscidini, Matteo Galli, Dan...
physics.optics cond-mat.mtrl-sci quant-ph