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We show that the nonlinear equation that describes nonparaxial Kerr propagation, together with the already reported bright-soliton solutions, admits of 1+1D dark-soliton solutions. Unlike their paraxial counterparts, dark solitons can be excited only if their asymptotic normalized intensity u?2 is below 3/7; their width becomes constant when u?2 approaches this value.

We investigate nonlinear propagation in the presence of the optical Kerr effect by relying on a rigorous generalization of the standard parabolic equation that includes nonparaxial and vectorial terms. We show that, in the 1+1‐D case, both soliton and propagation-invariant pattern solutions exist (while the standard hyperbolic-secant function is not a solution).

We demonstrate electro-optic spatial two-dimensional mode switching in a bulk sample of potassium lithium tantalate niobate. Spatial confinement, mode coupling, and electro-optic functionality are mediated by two photorefractive needle solitons of opposite electroholographic charges embedded together in their anisotropic lobular structure.

Developing a complete vectorial description of optical nonparaxial propagation of highly focused beams in Kerr media, we disclose a family of new phenomena. These phenomena appear to emerge as a consequence of the mutual coupling of all three components of the optical field. This circumstance, which is intrinsic to the very nature of Kerr propagation, was previously discarded on the basis of the conjecture that a reduced system is possible in which only one transverse field component interacts with the longitudinal component.

An exact result for the spectral density of intensity variations that occur after propagation of ergodic light in a medium having lowest-order-only group-velocity dispersion is obtained and applied to the problem of semiconductor laser phase noise to intensity noise conversion in a single-mode optical fiber. It is shown that the intensity spectrum after propagation formally approaches, for a large laser linewidth or a long (or high-dispersion) fiber, the intensity spectrum of a thermal source having the same line shape as the laser.

An exact result for the spectral density of intensity variations that occur after propagation of ergodic light in a medium having lowest-order-only group-velocity dispersion is obtained and applied to the problem of semiconductor laser phase noise to intensity noise conversion in a single-mode optical fiber. It is shown that the intensity spectrum after propagation formally approaches, for a large laser linewidth or a long (or high-dispersion) fiber, the intensity spectrum of a thermal source having the same line shape as the laser.

The influence of the temporal-coherence properties of the pump and signal waves on the efficiency and the temporal fidelity of the phase-conjugation process associated with degenerate four-wave mixing is examined.

The formalism of coupled-mode theory is adopted for describing nonlinear pulse propagation in optical fibers, the coupling being induced by the nonlinear part of the refractive index. This approach describes in a natural way the influence of the waveguide, and in principle allows of the possibility of investigating soliton propagation when more than one mode is excited.

We report the first observation of spatial one-dimensional photorefractive screening solitons in centrosymmetric media and compare the experimental results with recent theoretical predictions. We find good qualitative agreement with theory.

The formalism of coupled-mode theory, specialized to the continuum of radiation modes, allows us to extend the standard parabolic wave equation to include nonparaxial terms and vectorial effects, and, in particular, to generalize the nonlinear Schrödinger equation that describes propagation in the presence of an intensity-dependent refractive index.

We investigate three-dimensional propagation in bulk Kerr media of beams possessing different widths in the two transverse dimensions, under the combined effects of self-focusing and diffraction. This allows us to elucidate the process of self-trapping and provides a quantitative interpretation of recent experimental observations of beam self-deflection [Barthelemy et al., Opt. Lett. 17, 844 (1992)].

We present a theoretical analysis of the stability of photorefractive spatial solitons along with experimental results that show that the solitons are stable for small-scale perturbations but break down when the perturbations exhibit a transverse scale comparable with the soliton size (cross section).

We study experimentally self-trapping of optical beams in photorefractive media and show that the trapping is inherently asymmetric with respect to the two (transverse) trapping dimensions. We also present experimental results that show how the sizes of the resultant photorefractive spatial solitons are independent (within their range of existence) of the amplitude of the externally applied electric field used to generate them.

A time-dependent analysis of an all-single-mode fiber-optic resonator is presented in which the input field is allowed to exhibit an arbitrary dependence on time. In particular, the transmissivity of the resonator is evaluated for an input field possessing an arbitrary temporal coherence, which allows one to consider the role of the source coherence time as compared with the fiber time delay.

We investigate the problem of transmitting the maximum fractional energy over a given length of a linear dispersive medium (e.g., a single-mode optical fiber) once the input pulse duration and the output detection time are assigned.

We predict self-focusing and self-trapping of optical beams propagating in unbiased centrosymmetric photorefractive crystals in the near-transition paraelectric phase, where the nonlinear response is proportional to the square of the diffusion space-charge field.

We measure the phase shift induced by the optical Kerr effect between the two orthogonally polarized states of a birefringent single-mode fiber. The associated noise, which can arise whenever amplitude fluctuations of the source are present, is discussed.

We present a general proof of the distortion-correction theorem, that is, of the possibility of correcting wave distortion by the technique of optical phase conjugation. The proof is valid for fully vectorial nonparaxial propagation in the presence of a tensorial refractive-index perturbation and backscattering of the incident field.

We present a general proof of the distortion-correction theorem, that is, of the possibility of correcting wave distortion by the technique of optical phase conjugation. The proof is valid for fully vectorial nonparaxial propagation in the presence of a tensorial refractive-index perturbation and backscattering of the incident field.

The influence of the relative values of mutual modal delay, source coherence time, and signal modulation time on the power fluctuations between the two polarization states of a single-mode optical fiber is investigated.

We investigate the way in which four-wave mixing in a waveguide is affected by chromatic dispersion. The frequency dependence of the associated phase-conjugate mirror reflectivity turns out not to be influenced by chromatic dispersion itself.

Soliton propagation in a multimode optical fiber in the presence of an intensity-dependent refractive index is investigated by means of a set of nonlinear coupled equations derived in the frame of coupled-mode theory. In particular, the conditions on modal amplitudes and modal dispersion necessary for soliton existence are derived.

The effect of intensity fluctuations and the finite coherence time of the field on the propagation of nonlinear optical pulses is discussed. In particular, the statistical properties of the carrier are shown to affect the power level for soliton propagation.