•Unique salinity sensor employing photonic crystal fiber is designed for the first time.•Infiltration of sea water in air holes offers high confinement loss and act as analyte core mode.•The designed ...sensor exhibit high sensitivity for the determination of salinity in seawater.•The high sensitivity for x and y-polarization is reported as 5405 and 5675nm/RIU, respectively.•Proposed PCF promises the large birefringence of the magnitude of 10^(-3).
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 5405nm/RIU for x-polarization and 5675nm/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.
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.
Under investigation in this paper is an inhomogeneous nonlinear Schrödinger–Maxwell–Bloch system with variable dispersion, nonlinearity and tapered functions which describes the propagation of ...optical pulses in an inhomogeneous erbium-doped tapered fiber. Under certain coefficient constraints, multi-soliton solutions are obtained by the Darboux transformation method and symbolic computation. In order to study the impact of tapering on soliton dynamics in an inhomogeneous erbium-doped periodic distributed amplification system, a specific form of tapered profile is considered.
We study the self-similar transmission of light beams through a tapered graded-index nonlinear waveguide amplifier with parabolic law nonlinearity. Especially we, for the first time ever, consider ...the influence of nonlocality in the tapered parabolic-law nonlinear medium, which is a generic property of real physical media. With the utilization of the similarity transformation method, we construct the exact analytical bright and dark similariton solutions of the generalized nonlinear Schrödinger equation with distributed diffraction, cubic and quintic nonlinearity, weak nonlocality, tapering effect, and linear gain or loss that governs the self-similar beam dynamics in such system. We discuss the control and dynamical behavior of the self-similar localized wave structures for different tapering profiles that are of relevance in practical applications. The results show that through appropriately choosing the tapering profile, the evolution dynamics of optical similaritons can be effectively controlled.
•Cubic-Quintic NLS equation with tapered weakly nonlocality is examined.•Optical similariton solutions are obtained using similarity transformation.•For the first time, in a tapered non-Kerr nonlocality medium, dynamics of similariton is investigated.•Various inhomogeneous profiles are employed to study the propagation dynamics.•The different dynamics of optical similariton are graphically illustrated.
D-Shaped PCF sensor working on the principle of Surface Plasmon Resonance is scrutinized in our work by Finite element method. Indium titanium oxide (ITO) is coated over the flat surface of the ...sensor and over it the analyte is placed which enhances the excitation of Plasmon in the intermediate surface which is the major part in sensing. In our work we have achieved the maximal spectral sensitivity of 50,000 nm/RIU accompanied by high resolution 4 × 10−4 RIU, and also maximum amplitude sensitivity of 1266.67 RIU−1. We have numerically investigated the SPR sensing performance by considering the diameter of the core which can be optimized by varying the air-hole diameter and also the proposed model enables the feasibility of D-shaped PCF structure with very high sensitivity near IR region. Among the proposed SPR sensors, our sensor achieved the highest sensitivity range and it can be used for various chemical and bio-sensing applications.
A nonlinear Schrödinger equation with the combined effects of variable nonlinearity and generalized external potentials is investigated. Three soliton solutions are generated by means of Darboux ...method through constructed Lax pair. We attained two constraints related to gain or loss function for considered equation via compatibility condition. Using three soliton solutions, influences of the inhomogeneous nonlinearity and harmonic potential on soliton structures are analysed by properly tailoring the loss or gain parameter. Specifically, via inelastic collision among three solitons, soliton switching characteristics is observed. Additionally, we explore the Modulation instability (MI) through linear stability analysis (LSA) and impact of nonlinearity profile is examined. The trigonometric, exponential and constant values have been chosen for loss or gain parameter to study the effect on the MI gain spectrum.
Through theoretical approach, two soliton solutions for nonautonomous inhomogeneous nonlinear Schrödinger - Maxwell Bloch (INLS-MB) equation is attained with the aid of Darboux transformation ...technique. Based on obtained solutions, bird and butterfly like wave pattern are attained for the specific choice of inhomogeneous coefficients. Especially, by means of dispersion management scheme, exponential profile is adopted for the dispersion coefficient in the governing two soliton solutions. Also, through the appropriate choices of control parameters in inhomogeneous function, the transition from bird shaped to butterfly shaped pulse is observed astoundingly. Finally, nonautonomous soliton switching achieved through soliton fission and fusion phenomenon which could be observed via properly manipulating dispersion and nonlinearity parameters. The obtained analytical results and graphical illustrations are may helpful for the design of soliton control system in fiber optic communication and soliton based optical switching.
In this work, the existence of nonlinear ring waves in the form of multi-solitons is investigated analytically by considering a non-isospectral Nonlinear Schrödinger (NLS) equation with external ...potential. In order to generate soliton solutions, Darboux transformation technique is employed based on the Lax pair. Due to inhomogeneous effect of non-isospectral parameter, we attained the various form of ring solitons. Moreover, transformation from bright ring to dark ring and dromion structure are also observed for the first time. This indicates that the structure of nonlinear wave is strongly dependent on the combined effects of non-isospectral functions and external potential. To illustrate the physical significant of the considered equation and obtained solutions, the 2D and 3D graphs are successfully plotted by selecting appropriate values of control parameters. Finally, we perform linear stability analysis on non-isospectral Nonlinear Schrödinger (NLS) equation to demonstrate the gain spectrum for different strength of nonlinearity.
We investigated the soliton solution for N coupled nonlinear Schrödinger (CNLS) equations. These equations are coupled due to the cross-phase-modulation (CPM). Lax pair of this system is obtained via ...the Ablowitz–Kaup–Newell–Segur (AKNS) scheme and the corresponding Darboux transformation is constructed to derive the soliton solution. One and two soliton solutions are generated. Using two soliton solutions of 3 CNLS equation, nonlinear tunneling of soliton for both with and without exponential background has been discussed. Finally cascade compression of optical soliton through multi-nonlinear barrier has been discussed. The obtained results may have promising applications in all-optical devices based on optical solitons, study of soliton propagation in birefringence fiber systems and optical soliton with distributed dispersion and nonlinearity management.
•We consider the nonlinear tunneling of soliton in birefringence fiber.•3-coupled NLS (CNLS) equation with variable coefficients is considered.•Two soliton solutions are obtained via Darboux transformation using constructed Lax pair.•Soliton tunneling through dispersion barrier and well are investigated.•Finally, cascade compression of soliton has been achieved.
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