The term photonic crystals appears because of the analogy between electron waves in crystals and the light waves in artificial periodic dielectric structures. During the recent years the investigation of one-, two-and three-dimensional periodic structures has attracted a widespread attention of the world optics community because of great potentiality of such structures in advanced applied optical fields. The interest in periodic structures has been stimulated by the fast development of semiconductor technology that now allows the fabrication of artificial structures, whose period is comparable with the wavelength of light in the visible and infrared ranges.

http://ieeexplore.ieee.org/iel5/6354/16969/00781867.pdf

Photonic crystals

A topical review of numerical and experimental studies of supercontinuum generation in photonic crystal fiber is presented over the full range of experimentally reported parameters, from the femtosecond to the continuous-wave regime. Results from numerical simulations are used to discuss the temporal and spectral characteristics of the supercontinuum, and to interpret the physics of the underlying spectral broadening processes. Particular attention is given to the case of supercontinuum generation seeded by femtosecond pulses in the anomalous group velocity dispersion regime of photonic crystal fiber, where the processes of soliton fission, stimulated Raman scattering, and dispersive wave generation are reviewed in detail. The corresponding intensity and phase stability properties of the supercontinuum spectra generated under different conditions are also discussed.

Supercontinuum generation, photonic crystal fiber

With symbolic computation, two classes of lump solutions to the dimensionally reduced equations in (2+1)-dimensions are derived, respectively, by searching for positive quadratic function solutions to the associated bilinear equations. To guarantee analyticity and rational localization of the lumps, two sets of sufficient and necessary conditions are presented on the parameters involved in the solutions. Localized characteristics and energy distribution of the lump solutions are also analyzed and illustrated.

Study of lump dynamics based on a dimensionally reduced Hirota bilinear equation

Optical Solitons From Fibers To Photonic Crystals

Associated with the prime number $$p=3$$
 , a combined model of generalized bilinear Kadomtsev–Petviashvili and Boussinesq equation (gbKPB for short) in terms of the function f is proposed, which involves four arbitrary coefficients. To guarantee the existence of lump solutions, a constraint among these four coefficients is presented firstly, and then, the lump solutions are constructed and classified via searching for positive quadratic function solutions to the gbKPB equation. Different conditions posed on lump parameters are investigated to keep the analyticity and rational localization of the resulting solutions. Finally, 3-dimensional plots, density plots and 2-dimensional curves with particular choices of the involved parameters are given to show the profile characteristics of the presented lump solutions for the potential function $$u=2(\mathrm{{ln}}f)_x$$
 .

Constructing lump solutions to a generalized Kadomtsev–Petviashvili–Boussinesq equation

We have investigated the femtosecond soliton propagation in inhomogeneous fiber, which is described by the modified inhomogeneous Hirota equation with variable coefficient (MIH-vc). With the aid of AKNS method, corresponding Lax pair is constructed. By virtue of the Darboux transformation method and symbolic computation, the analytic one- and two-soliton solutions are explicitly obtained. Using obtained solutions, we graphically discuss the features of femtosecond solitons in modified inhomogeneous Hirota system by changing the profile of variable coefficients. We analyze various form of group velocity dispersion, third order dispersion and nonlinearity parameter for periodic amplification system, exponentially distributed system, parabolic solitons, periodic exponentially modulated system, which will be observable in the future experiments. These results are potentially useful in future experiments and soliton control for long-distance optical communication. Finally, the soliton solutions of the MIH-vc equation in double Wronskian form is constructed and further verified using the Wronskian technique by substitute in bilinear equations.

Nonautonomous solitons in modified inhomogeneous Hirota equation: soliton control and soliton interaction

A salinity sensor employing photonic crystal fiber is designed for measuring the concentration of salt in sea water. The sea water sample is infiltrated into one of the air holes in cladding, which offers high confinement loss and act as an analyte core mode and background acts as silica mode. In order to satisfy the phase matching condition, the power transferred from silica core to the liquid filled analyte core, which is investigated using finite element method. An enhanced sensitivity of salinity in sea water reports as 5405 nm/RIU for x -polarization and 5675 nm/RIU for y -polarization with a detection limit of 0.0037 RIU has been reported. The proposed PCF also promises to yield the large birefringence of order 10 −3 along with the enhanced sensitivity.

Salinity sensor using photonic crystal fiber

In this paper, we investigated the nonlinear tunneling of soliton in coupled higher order nonlinear Schrodinger (CHNLS) equations. Corresponding Lax pair for this equation is acquired through the Ablowitz-Kaup-Newell-Segur (AKNS) method and two soliton solutions is derived using Darboux transformation. Using two soliton solution of CHNLS equation, nonlinear tunneling of soliton has been investigated. Ultimately, cascade compressions of optical soliton have been investigated by soliton passing through number of nonlinear tunneling barrier. The obtained results may have promising applications in all-optical devices based on optical solitons.

M.S. Mani Rajan

Papers

Nonautonomous solitons in modified inhomogeneous Hirota equation: soliton control and soliton interaction

Salinity sensor using photonic crystal fiber

Dispersion management and cascade compression of femtosecond nonautonomous soliton in birefringent fiber

D-shaped PCF sensor based on SPR for the detection of carcinogenic agents in food and cosmetics

Observation of two soliton propagation in an erbium doped inhomogeneous lossy fiber with phase modulation