EXPERIMENTS ON SEEDED AND NOISE INITIATED MODULATIONAL INSTABILITY IN LiNbO_3 SLAB WAVEGUIDES

摘要

We report the experimental study of seeded and noise initiated modulational instability (MI) during second harmonic generation in a LiNbO_3 slab waveguide. In the non-seeded case, two MI initiating mechanisms were identified, namely random noise on the input beam and waveguide imperfections. We also measured the MI gain coefficient as a function of periodicity and beam intensity employing a small, well-defined periodic perturbation (seeding). Excellent agreement with theory was obtained.