Quantum-state-preserving optical frequency conversion and pulse reshaping by four-wave mixing

Nondegenerate four-wave mixing driven by two pulsed pumps transfers the quantum state of an input signal pulse to an output idler pulse, which is a frequency-converted and reshaped version of the signal. By varying the pump shapes appropriately, one can connect signal and idler pulses with arbitrary durations and shapes. This process enables a variety of functions required by quantum information networks.