J.P. Saini

Modal Analysis and Dispersion Curves of a New Unconventional Bragg Waveguide Using a Very Simple Method

A theoretical modal dispersion study of a new unconventional Bragg waveguide having hypocycloidal core cross-section and surrounded by Bragg cladding layers is presented using a very simple boundary matching technique [1]. An attempt has been made to determine how the modal characteristics of a standard Bragg fiber change as its circular shape is changed to the hypocycloidal shape. It is seen that in the case of a hypocycloidal Bragg waveguide single mode guidance is possible when V ≤ 10.0 where V is the normalized frequency parameter. 192 Singh, Prajapati, and Saini

MODAL ANALYSIS AND DISPERSION CURVES OF A BRAGG FIBER HAVING ASYMMETRIC LOOP BOUNDARY

An analysis of the modal propagation characteristics of a Bragg fiber having asymmetric loop boundary is made, using a simple matrix method. The boundary condition is replaced by matrix equation andthe modal eigen value equation is obtainedunder weak guidance condition. The computed results are shown in the form of d ispersion curves andcutoff frequencies andare comparedwith the dispersion curves of a standard Bragg fiber having circular core cross section. It is seen that the proposedBragg fiber with a small number of claddings (two of four) shows comparable or even better performance than the standard Bragg fiber with respect to a few mode-guidance properties.

Modal analysis and dispersion curves of an elliptical W-type single mode fiber

In this paper, the propagation of electromagnetic waves in W-type elliptical dielectric optical fiber having various cladding layers is presented. The presented fiber has concentric core and cladding which have elliptical cross section and the refractive index of one of the inner cladding (the cladding between first clad and last clad) maximum. Using elliptic cylindrical coordinates, boundary conditions are derived and longitudinal field components for the even and odd modes are obtained. The characteristic equation for the fiber to be studied is determined by solving the Mathieu (q > 0) and the modified Mathieu functions (q < 0). In order to study the fundamental mode, the modal index m is put as m = 1. Finally, the cutoff frequencies for several lower order modes have been calculated and their dispersion characteristics are plotted. The effects of elliptical eccentricity e on the mode cutoff frequencies and mode transmissions are also addressed. The analysis shows that one can control the propagation property of optical fiber by increasing the number of inner claddings. These claddings provide additional degree of freedom to control the modes.

Effect of plasma on modal dispersion characteristics of elliptical Bragg waveguide

In this paper, the dispersion characteristics of a plasma filled elliptical Bragg waveguide is investigated. The modal characteristic equations of the proposed Bragg waveguide for both ω > ωp and ω < ωp are derived. The effects of plasma frequency, numbers of cladding layers and the eccentricity of elliptical Bragg waveguide on the dispersion characteristics are studied. The analysis shows that the introduction of plasma in the proposed waveguide allows to control the propagation of modes.

Analysis of a metal clad waveguide sensor having metamaterial as a guiding layer

Abstract In this study a metal clad waveguide sensor with a metamaterial guiding layer is analyzed. Sensitivity of the proposed sensor is derived using dispersion and Fresenal’s equations for waveguiding mode and reflection mode. While efficiently analyzing and comparing the results with the existing one, some interesting findings are achieved. It is observed that the proposed sensor shows larger cover layer sensitivity and larger adlayer sensitivity compared to the dielectric guiding layer sensor due to adsorbtive properties of metamaterial. Henceforth, it concludes that the proposed sensor shows sensitivity improvement over a dielectric guiding layer sensor.

Analytical analysis of sensitivity of optical waveguide sensor

In this article, we carried out analytical analysis of sensitivity and mode field of optical waveguide structure by use of effective index method. This structures as predicted have extended mode which could interact with the surrounding analyses in a much better way than the commonly used EWS.

Dispersion characteristics analysis of wave propagation in hollow clad elliptical waveguide

The propagation of guided electromagnetic waves in hollow clad elliptical waveguide in which an elliptical core lies between cladding layer have the different refraction index is investigated here. The allowed mode for hollow clad elliptical waveguide structure is calculated by solving a dispersion equation of hollow optical waveguide that is expressed in terms of Mathieu functions. We find that the dispersion curves are discontinuous and modes are exists only in particular wavelength bands. So, the proposed waveguide structure can be applied as filter or to reduce nonlinear effects in optical fiber communication. Dispersion curves are obtained for different eccentricities of the elliptical shape of the fiber.

Effect of a Metamaterial and Silicon Layers on Performance of Surface Plasmon Resonance Biosensor in Infrared Range

Metamaterial based surface plasmon resonance biosensor for enhancement of performance parameters at near infrared wavelengths is presented. The thickness of the metamaterial layer and gold layer were optimized at near infrared wavelengths. The performance parameters of the SPR sensor are defined in terms of sensitivity, detection accuracy and quality factor. By the addition of a metamaterial layer the sensitivity is enhanced but the quality factor and detection accuracy is slightly decreased. Hence, further to increase the quality factor and detection accuracy a silicon layer is included between the gold and metamaterial layers. It was observed that the full width at half maximum (FWHM) of reflectance curve is minimized up to great extent with little decrement in the sensitivity due to the inclusion of the silicon layer.

Field Confinement of Stacked Multilayer Slab Waveguide Using Graphene

The electromagnetic field confinement in nano carbon stacked multilayer graphene (s-MLG) structure of four layer slab waveguide is presented. The effect on field confinement by increasing the number of graphene layers is analyzed.