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We demonstrate specular photonic "lattices" with random index variations at disordered positions of lattice sites. These amorphous lattice structures, optically induced in a bulk nonlinear crystal, remain invariant during propagation since they are constructed from random components residing on a fixed ring in momentum space. We observe linear spatial localization of a light beam when probing through different "defect" points in such specular lattices, as well as the nonlinear destruction of localized modes. In addition, we illustrate the possibility of image transmission through the disordered lattices, when a self-defocusing nonlinearity is employed.

We demonstrate both theoretically and experimentally that photonic lattices under self-defocusing nonlinearity support gap solitons in various shapes such as cross and H shapes. These solitons, with their intensity humps all in-phase, are stable against perturbations, thus they propagate robustly throughout the lattices. Based on this finding, we propose soliton-based text/image transmission through bulk photonic structures.

We demonstrate a ring-shaped Bessel-like photonic lattice akin to a photonic bandgap fiber with a low-index core. While the ring lattice is optically induced in a bulk crystal with a self-defocusing nonlinearity, guidance of a probe beam propagating linearly through the core is clearly observed. The possible mechanism for such guidance is also discussed.

We present both experimental and theoretical results on discrete solitons in two-dimensional optically-induced photonic lattices in a variety of settings, including fundamental discrete solitons, vector-like discrete solitons, discrete dipole solitons, and discrete soliton trains. In each case, a clear transition from two-dimensional discrete diffraction to discrete trapping is demonstrated with a waveguide lattice induced by partially coherent light in a bulk photorefractive crystal. Our experimental results are in good agreement with the theoretical analysis of these effects.

We study wave propagation in a two-dimensional photonic lattice with focusing Kerr nonlinearity, and report on the existence of various nonlinear localized structures in the form of fundamental, dipole, and vortex solitons. First, the linear bandgap structure induced by the two-dimensional photonic crystal is determined, and solitons are found to exist in the photonic bandgap. Next, structures of these solitons and their stability properties are analyzed in detail. When the propagation constant is not close to the edge of the bandgap, the fundamental soliton is largely confined to one lattice site; the dipole soliton consists of two p-out-of-phase, Gaussian-like humps, whereas the vortex comprises four fundamental modes superimposed in a square configuration with a phase structure that is topologically equivalent to the conventional homogeneous-bulk vortex. At high lattice potential, all these soliton states are stable against small perturbations. However, among the three states, the fundamental solitons are the most robust, whereas vortices are the least. If the propagation constant is close to the edge of the bandgap, then all three soliton states spread over many lattice sites and become linearly unstable as a result of the Vakhitov‐Kolokolov instability. © 2004 Optical Society of America OCIS codes: 190.0190, 190.5530.

We determine the transient evolution of the probability distribution of the polarization dispersion vector both analytically and numerically, using a physically reasonable model of the fiber birefringence. We show that, for all practical birefringence parameters, the distribution of the differential group delay (DGD), which is the magnitude of the polarization dispersion vector, becomes Maxwellian in just a few kilometers, except in the tail region, where the DGD is large. In this limit, the approach to a Maxwellian distribution takes much longer, of the order of tens of kilometers. In addition, we show that in the transient regime the DGD distribution is very different from Maxwellian. We also find that the probability-distribution function for the polarizationdispersion vector at the output of the fiber depends upon the angle between it and the local birefringence vector

We show, by performing linear stability analysis and direct numerical simulations, that dark-soliton transverse instability is significantly reduced in Kerr media by strong coupling to a bright soliton. High instability suppression can be achieved by use of large-amplitude bright solitons.

We develop a perturbation theory to calculate analytically the effects of interchannel collisions on Gaussian pulses in a wavelength-division-multiplexed (WDM) system with moderate and strong dispersion management (DM). The losses are assumed to be balanced by the amplification and are not explicitly included into the model. We show that, for complete collisions, the collision-induced frequency shift of a Gaussian pulse is negligible, whereas for incomplete collisions (those with initially overlapped pulses) this shift is significant. We also show that, as the DM strength increases, the collision-induced position shift becomes more important than the frequency shift produced by the incomplete collision. Another result is that the collisional shifts depend on the DM strength and the path-average dispersion but not on the lengths of the two fiber segments in the DM cell. We check the fully analytical predictions against direct PDE simulations and find satisfactory agreement between them. We also give an estimate of the limit imposed on the transmission distance in the WDM soliton systems by the interchannel collisions. © 1999 Optical Society of America [S0740-3224(99)00410-5] OCIS codes: 060.0060, 060.2330, 060.4230, 060.5530.

We develop a perturbation theory to analytically calculate the effects of complete and incomplete interchannel collisions of Gaussian pulses in a wavelength-division-multiplexed system with strong dispersion management. We show that, for complete collisions, the collision-induced frequency shift of a Gaussian pulse is negligible, whereas its position shift is significant and can be found in a simple analytical form. For strong dispersion management we find that incomplete collisions can be neglected, whereas for dispersion management of moderate strength the contribution of the incomplete collisions can be significant. The analytical predictions are in satisfactory agreement with numerical results. We also give an estimate of the limit imposed on the transmission distance by such collisions.