Few-cycle vector solitons in nonlinearly coupled waveguides

Few-cycle vector optical solitons in two nonlinearly coupled adjacent waveguides are analyzed by means of modified Korteweg-de Vries type equations. Symmetric breathers are found to yield unstable solutions. We obtain analytical solutions where the two components are proportional and such optical waveforms are shown to be stable. Excited versions of them, in which the amplitudes of the components oscillate during the propagation, are evidenced numerically.