Browsing by Author "R. Jatan"

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An analytical study of a doubly clad compressed ellipse optical waveguide
(2014) S.P. Singh; R. Jatan; R. Janma; B.D. Singh; Vivek Singh; M.P.S. Rao
Using an analytical method based on boundary matching technique, the modal behavior and cutoff frequencies of a compressed ellipse doubly clad optical waveguide is studied. The proposed waveguide consists of a core region of higher refractive index with two cladding regions: one is inner cladding and the other is outer cladding. We take appropriate orthogonal coordinates for the proposed structure and impose the boundary conditions to obtain the characteristic equation. The effect of the width of inner cladding layer on the dispersion characteristic is observed. It is found that the width of inner cladding is able to tailor the dispersion characteristic and cutoff condition of the waveguide up to a certain limit. © 2013 Elsevier GmbH.
Modal analysis and cutoff frequencies of a doubly clad plasma loaded waveguide having a lemniscates of Bernoulli-type core cross-section
(2011) R. Janma; R. Jatan; S.P. Singh; P. Dwivedi; V. Dwivedi; Vivek Singh
The modal dispersion characteristics of EM waves in a new unconventional plasma loaded doubly clad waveguide having a shape of the lemniscates of Bernoulli-type core cross-section have been studied analytically. The proposed waveguide has three parts namely the core with slighter high index, the inner cladding with plasma and the outer cladding with air. Now using the necessary orthogonal coordinates for the proposed structure and imposing the boundary conditions under the weak guidance condition, the modal characteristics equation has been obtained considering variations in plasma width and plasma frequency, the dispersion curves and cutoff frequencies have been obtained and presented in this paper. It is noted that as the width of plasma layer increases, the cutoff frequency also increases considerably in all considered cases. This shows that using plasma width as a new parameter we can control any particular mode on our wish. © 2010 Published by Elsevier GmbH.
Modal analysis of a doubly clad optical waveguide having a cross-section of the shape of a lemniscate
(2009) R. Janma; R. Jatan; S.P. Singh; P. Dwivedi; V. Dwivedi; Vivek Singh
In this paper, we choose a simple analytical method based on scalar wave approximation to study the modal behaviour of an unconventional doubly clad optical waveguide having a cross section of the shape of a lemniscate. We take the appropriate orthogonal coordinates for the proposed structure and impose the boundary conditions under the weak guidance approximation to get the modal eigen value equation. Using this equation we obtain numerical results in the form of dispersion curves and cutoff frequencies. An attempt has been made to estimate how the modal behaviour changes when a single cladded waveguide having a lemniscates of Bernoulli type core cross-section is changed to a waveguide having double cladded shape of a lemniscate. It is noted that the double cladded waveguide provides an additional degree of freedom to control the cutoff frequencies on our choice. © 2009 Springer Science+Business Media, LLC.