Existence of solitary waves in optical fibers owing to the mutual support between bright and dark pulses.

We introduce a new type of solitary wave in a lossless single-mode fiber in which a bright solitonlike pulse in the anomalous-dispersion range propagates together with a stationary dark pulse in the normal-dispersion range. Such a solitary wave can be generated by launching a bright pulse in the anomalous-dispersion range together with a long pulse of the same speed in the normal-dispersion range into a fiber. The results of numerical simulations show that the dark pulse is not a dark soliton. The generation and maintenance of such a solitary wave are attributed to the mutual chirping through cross-phase modulation between those two waves in the anomalous- and normal-dispersion ranges.