In an optical parametric device that uses LiNbO 3 crystals and that is being pumped by a Nd:YAG laser, three second-order nonlinear optical processes can simultaneously take place for a specific orientation of the crystals. These processes are parametric amplification, second-harmonic generation of the signal and difference-frequency mixing of the doubled signal and the idler. The simultaneous occurrence of these processes is due to the unique fact that the phase-match angle-tuning curves for the two processes intersect and that the angle-tuning curve of the third process lies very close to the intersection point. This phenomena is used to generate efficiently tunable pulses with a minimum number of crystals.