Self- and cross-phase modulation in a PPLN OPO

Summary form only given. Quasi-phase-matching (QPM) has been demonstrated as a reliable technique in the operation of efficient optical parametric oscillators (OPOs). Periodically poled lithium niobate (PPLN) has become established as an efficient nonlinear material for QPM second-order nonlinear processes and has been used in many experiments. Often these experiments demand transform-limited ultrashort OPO pulses. Even with high-quality pump pulses, however, the OPO pulse bandwidth can be broadened by self- and cross-phase modulation because of the high-intensity pulses required for the pumping. Selfand cross-phase modulation can be important in an OPO based on PPLN and pumped by ps and fs pulses even though lower pump intensities are required in this material. Self- and cross-phase modulation in a synchronously pumped OPO based on a multigrating periodically poled LiNbO/sub 3/ crystal pumped by a 1055-nm, mode-locked Nd:glass laser with negative feedback (train of 250 pulses with duration 1.5 ps) has been investigated in the experiment.