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K Porsezian

Publications and source records attributed to K Porsezian.

10 recordsLinked to original sources
PubMed2005

Self-similar propagation and compression of chirped self-similar waves in asymmetric twin-core fibers with nonlinear gain.

Ultrashort-pulse propagation in asymmetric twin-core fiber amplifiers is studied with the aid of self-similarity analysis of the nonlinear Schrödinger-type equation interacting with a source, variable dispersion, variable Kerr nonlinearity, variable gain or loss, and nonlinear gain. Exact chirped pulses that can propagate self-similarly subject to simple scaling rules of this model have been found. It is reported that the pulse position of these chirped pulses can be precisely piloted by appropriately tailoring the dispersion profile. This fact is profitably exploited to achieve optimal pulse compression of these chirped self-similar solutions.

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PubMed2005

Variational approach to spatial optical solitons in bulk cubic-quintic media stabilized by self-induced multiphoton ionization.

Propagation of an optical high-power cylindrically symmetric beam in a material characterized by cubic-quintic nonlinearity is studied both analytically and numerically. In this case we have to consider the self-defocusing effect caused by the presence of free electrons produced due to plasma formation. The variational method is used to study the system analytically. The finite-difference beam propagation method is used for the numerical analysis. Stable (2+1) D spatial solitons are observed. The analytical results are found to be in very good agreement with the numerical results.

Journal Article↗
PubMed2005

Nonlinear compression of solitary waves in asymmetric twin-core fibers.

We demonstrate a different pulse compression technique based on exact solutions to the nonlinear Schrödinger-type equation interacting with a source, variable dispersion, variable Kerr nonlinearity, and variable gain or loss. We show that this model is appropriate for the pulse propagation in asymmetric twin-core fibers. The chirped pulses are compressed due to the nonlinearity as well as dispersion management as also due to the space dependence of the gain coefficient. We also obtain singular solitary wave solutions, pertaining to extreme increase of the amplitude due to self-focusing.

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PubMed2005

Generation of Bragg solitons through modulation instability in a Bragg grating structure.

In this article, we consider the continuous wave (cw) propagation through the nonlinear periodic structure that consists of alternating layers of both positive and negative Kerr coefficients along the propagation direction. We investigate the modulational instability (MI) conditions required for the generation of ultrashort pulses for the nonlinearity management system. We study the occurrence of MI at the top and bottom edges of the photonic band gap (PBG) where the forward and backward propagating waves are strongly coupled because of the presence of the grating structure. We also study the MI when cw is detuned from the edges of the PBG into the anomalous and normal dispersion regimes. In addition, we discuss the existence of gap solitons for the nonlinearity management system in the upper and lower branches of the dispersion curve through the MI gain spectra. We observe the generation of higher order solitons in the nonlinear periodic structure when the input power is increased beyond a certain critical level. Finally, we discuss the generation of higher order Bragg grating solitons through the intensity evolution of the forward and backward propagating fields.

Algorithms↗
PubMed2003

Soliton propagation in an erbium-doped fiber with and without a continuous wave background.

Considering ultrashort pulse propagation in a nonlinear resonant fiber governed by Hirota-Maxwell Bloch equations, the soliton interaction in an erbium-doped fiber system associated with higher-order dispersion, self-steepening, and self-induced transparency effects is studied for the case when the fiber is driven with and without a constant pumping source. Using auto-Bäcklund-transformation, one- and two-soliton solutions are generated. The significance of the results is discussed in detail.

Journal Article↗
PubMed2003

Alternative coupled integrable optical soliton system with higher-order effects.

The system of coupled Hirota equations, which explains the simultaneous propagation of two fields in a nonlinear optical fiber with the inclusion of higher-order linear and self-steepening effects, is considered. By making use of a Painlevé singularity structure analysis, the system is found to be an exactly integrable soliton system for three choices of physical parameters. Two of the soliton conditions are already well studied. For the third system, the soliton solutions are obtained using bilinear forms.

Journal Article↗
PubMed2001

Propagation of dark solitons with higher-order effects in optical fibers.

In this paper, we analyze dark soliton propagation in nonlinear optical fibers with higher-order effects such as third order dispersion, self-steepening, and stimulated Raman scattering. We consider the Hirota equation and the higher-order nonlinear Schrödinger equation, and identify conditions for dark soliton propagation through Painlevé analysis. We also construct an explicit Lax pair, and Hirota bilinear form is used to generate one and two dark solitons.

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