B. Crosignani

Vectorial analytical description of propagation of a highly nonparaxial beam

AbstractWe present a formalism describing optical propagation in a homogeneous medium of a fully vectorial highlynonparaxialfield,characterizedbyawaistsmallerthanthewavelength.Themethodallowsustoderiveananalyticalexpressionforafieldpossessing aninitialGaussiantransversedistributionofwidth w,intheextremenonparaxialregimew 1,is becoming more andmore important with the advent of new opticalstructures, like, e.g., microcavities and photonicband-gap crystals [4], possessing linear dimen-sionsorspatialscalesofvariationcomparableoreven smaller than k. The description of highlynonparaxialfieldsiscommonlyachievedthroughan ab initio numerical solution of Maxwell’sequationandturnsouttobetimeconsumingandnot particularly illuminating. Thus, it is natural

Optical multistability in a fiber-optic passive-loop resonator

Abstract The nonlinear phase-shift, unavoidably induced in an electromagnetic field circulating in a fiber-optic passive-loop resonator by the presence of the optical Kerr effect, gives rise to a multistable behavior of the input-output characteristics at relatively low optical powers.

Vectorial free-space optical propagation: a simple approach for generating all-order nonparaxial corrections

Abstract We present a rigorous approach to the problem of fully vectorial nonparaxial propagation in free space. This treatment allows us to generalize in a simple way current approximated schemes of solution.

Finite-dimensional description of nonlinear pulse propagation in optical-fiber couplers with applications to soliton switching

We have developed a general formalism able to describe nonlinear pulse propagation in multimode optical fibers or waveguide couplers by means of a finite number of parameters, which are functions of the traveled distance. These parameters possess a direct physical meaning and can be interpreted, for a wide class of time-dependent interaction phenomena, as conjugate variables of a suitable Hamiltonian. The accuracy and the importance of the method are discussed with reference to a specific example of bimodal optical propagation, involving soliton switching and soliton instabilities.

Miniaturization and embedding of soliton-based electro-optically addressable photonic arrays

Using top-electrodes, we demonstrate the soliton-based miniaturized integration of electro-optic devices in a photorefractive paraelectric bulk crystal. Self-trapping and beam manipulation though soliton electro-activation is achieved at quasi-digital voltages.

Depolarization of light due to the optical Kerr effect in low-birefringence single-mode fibers

The evolution of the state of polarization of an electromagnetic field propagating in a low-birefringence single-mode fiber in the presence of the nonlinear interaction associated with the optical Kerr effect is investigated. We explicitly evaluate the degree of polarization P(z) as a function of the fiber length z for a completely polarized input field [P(0) = 1] possessing an exponential intensity distribution, such as the one furnished by a multimode laser. Furthermore, the asymptotic value P(∞) corresponding to an arbitrary distribution of the input intensity is determined.

Self-focusing and self-trapping in unbiased centrosymmetric photorefractive media

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.

Coupled-mode theory and slowly-varying approximation in guided-wave optics

Abstract We show that the slowly-varying approximation usually adopted in the frame of coupled-mode theory is actually unnecessary.

On the statistics of Gaussian light scattered by a Gaussian medium

The probability distribution of photon-counting relative to a Gaussian beam scattered by a Gaussian medium is evaluated.

Light scattering by particles suspended in a turbulent fluid

The spectrum of light scattered by particles suspended in a turbulent fluid is investigated theoretically.