Solitons in a periodic structure with Kerr nonlinearity

On the basis of coupled-mode theory, a new class of solitary solutions for the electromagnetic wave propagating in an infinite one-dimensional lossless periodic structure with an intensity-dependent refractive index is presented. In contrast to in-gap solitons, the solitary solutions have, in general, their carrier frequency outside the frequency gap of the periodic structure. They show some remarkable properties: bright soliton and dark soliton solutions, bistability, and straight-speed propagation.<
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