Properties of type II quadratic solitons excited by imbalanced fundamental waves.

It was shown experimentally for type II second-harmonic generation in KTP that the family of quadratic spatial solitons exists over a wide range of imbalances for the two fundamental wave inputs. The threshold for soliton formation was measured as a function of both phase mismatch and relative input fraction of the energy in the two fundamental polarizations. Launching unequal fundamental inputs led to an imbalanced three-coupled-field output composition.

Modulational instability of a strip beam in a bulk type I quadratic medium.

The evolution of a strip (one-dimensional) fundamental beam with propagation distance owing to spatial modulational instabilities was analyzed in a quadratic medium near type I phase matching. We obtained the gain coefficient for the modulational instability and showed that the wave evolves into a clean periodic sequence of solitary waves and does not reproduce the incident beam.

Combined influence of amplifier noise and intrapulse Raman scattering on the bit-rate limit of optical fiber communication systems.

Amplified spontaneous emission noise generates fluctuations in soliton energy and therefore fluctuations in the Raman self-frequency shift and in the group velocity. The corresponding timing jitter is found to be the main limitation for communication distances less than 1500 km.