Optical pulse source having variable repetition rates and wavelengths

摘要

An optical pulse source 30 comprising a DPSS pump laser 31, a photonic crystal fibre (PCF) 35 and acousto-optic modulator (AOM) gating means 33. The pump pulses are coupled through lenses 32 to the AOM 33, synchronised to the pump laser 31 and operable to gate the pump pulses to a reduced repetition rate Rr = Rf/N, where Rf is the pump laser fundamental frequency. The pulses from the AOM 33 are injected via optics 34 into the PCF 35. Propagation through the PCF 35 causes the pulses to broaden spectrally to produce supercontinuum pulses. An optical pulse source comprising the optical pulse source 30 and an acousto-optical tunable filter (AOTF) operable to convert supercontinuum pulses into wavelength variable output pulses is also provided. A method of scaling the energy of the optical supercontinuum pulses is also provided.