Three-wave soliton interaction of ultrashort pulses in quadratic media

Analytical soliton solutions of the nonlinear three-wave-interaction (TWI) equations are generalized to include phase mismatch $\mathrm{\Delta }k.$ These solutions describe the interaction of so-called TWI solitons. The TWI-soliton and near-TWI-soliton regimes show high-second-harmonic and sum-frequency compression with insignificant satellite pulses for a wide range of nonlinear crystals. Analysis of the solutions shows large time and phase shifts of the fundamentals after the interaction. These shifts are fairly insensitive to the phase mismatch (the dependence is second order in $\mathrm{\Delta }k$), which may make them useful in all-optical switching devices.