Phase modulation transfer in mirrorless optical parametric oscillators

In this work we provide experimental and theoretical investigation on the temporal phase transfer characteristics in MOPO. In particular we show that the phase modulation is transferred primarily to the signal wave while the idler wave remains almost phase-modulation-free. This property allows a simple means for generating transform-limited pulses in mid-infrared spectral region regardless of phase modulation of the pump. Theoretical simulation reveals that the amount of remaining phase modulation in the idler wave depends on the group-velocity mismatch between the co-propagating pump and signal waves.