Five optical cycle pulse generation in the mid-infrared from an optical parametric oscillator based on aperiodically-poled lithium niobate

Summary form only. Femotsecond quasi-phase matched (QPM) optical parametric oscillators (OPOs) that use crystals with a uniform grating period are subject to bandwidth limiting effects such as temporal walk-away and frequency up/back conversion, which become increasingly more significant for shorter pump pulses. These effects can be minimised by designing crystals with non-uniform grating periods to match a chirped broad-bandwidth pump pulse. If the signal wave is assumed narrow bandwidth then an appropriately chirped pump pulse can be arranged to combine with the signal wave at differing positions throughout the crystal such that all idler components will leave simultaneously as a transform limited pulse. We present the results of an aperiodically poled LiNbO/sub 3/ optical parametric oscillator.