Intracavity synchronously pumped PPLN picosecond optical parametric oscillator

Abstract

ABSTRACT The goal of our work is the development of intracavity synchronously pumped optical parametrical oscillator(OPO), generating two trains of picosecond pulses inside a single cavity. These trains have the same repetitionrate but they are independent and can dier in phase and carrier frequency. They can interfere on a detector,producing a beat note at the carrier frequency dierence. This allows to determine very precisely the phasedierence between them which is possible to use in all sensor applications where the measured physical quantityis converted into phase dierence between two counter-circulating pulses. We designed a synchronously pumpedOPO with nonlinear crystal (MgO:PPLN) for parametric generation inserted inside a linear resonator of a mode-locked diode pumped Nd:YVO 4 laser. This con“guration ensures the same way for signal and pumping wavesthrough the crystal and reduces the dead-band of the beat signal. We observed that the OPO could generate inthree regimes: the desired dual pulse operation when the pump pulse produces parametric waves during bothforward and return passes through PPLN crystal. Two single pulse OPO operations are possible when parametricinteraction occurred only during one pass of the pump pulse through the PPLN crystal in forward or backwarddirection.Keywords: Parametric oscillator, synchronous pumping, mode-locked Nd:YVO