  We report on the experimental observation of induced solitons in a passively
mode-locked fiber ring laser with birefringence cavity. Due to the cross
coupling between the two orthogonal polarization components of the laser, it
was found that if a soliton was formed along one cavity polarization axis, a
weak soliton was also induced along the orthogonal polarization axis, and
depending on the net cavity birefringence, the induced soliton could either
have the same or different center wavelengths to that of the inducing soliton.
Moreover, the induced soliton always had the same group velocity as that of the
inducing soliton. They form a vector soliton in the cavity. Numerical
simulations confirmed the experimental observations.
