CLEO:

Tao Lu, Lan Yang, Rob V.A. van Loon, Albert Polman and Kerry J. Vahala,
An On-Chip Erbium Doped Three-Photon Upconversion Silica Microlaser Emitting at GreenWavelengths

M. Hossein-Zadeh and K. J. Vahala,
Photonic RF-receiver based on all-optical down-conversion in an optomechanical oscillator