Efficient four wave mixing from a picosecond fibre laser in photonic crystal fibre

Here we focus on efficient generation of discrete wavelengths around 700 nm by four-wave mixing (FWM) offering high power in a narrow band. Fibre dispersion plays a key role in phase matching conditions for nonlinear processes such as FWM, and PCFs offer unique ability to tailor the dispersion properties for a particular application through proper modification of the pitch (A) and the relative airhole diameter (d/A). Various fibres have already been designed to provide a range of short signal wavelength between 686 nm and 975 nm and good conversion efficiency were demonstrated when fibres are pumped with a 1064 nm Q-switched microchip laser emitting 0.6 ns pulses.