Rajeev Jindal

Design of a high negative chromatic dispersion in a single mode optical fibre : effect of the central index dip

In this paper, we present the simulation results, using a cylindrical coordinates beam propagation method, of the effect of the central index dip in an optical fibre with high negative chromatic dispersion at 1.55 μm. This leads to the definition of an equivalent core area dependence of the position and the amplitude of the negative chromatic dispersion value achieved using such fibre geometry.

Planar optical waveguides with arbitrary index profile: an accurate method of analysis

We present here an improvement of the existing modified Airy function (MAF) method. The results of our study show that the improvement gives extremely accurate propagation constants and also the modal fields for planar waveguides with arbitrary index profile.

Bending induced phase shifts in arbitrarily bent rectangular-core dual-mode waveguides

We examine the variation of the effective indexes of the two modes of an arbitrarily bent dual-mode rectangular-core waveguide. We find that under the large bending radius approximation, which is indeed the practical case for most of the devices, the waveguide bent with bending radius /spl rho/ in a plane at an angle /spl theta/ with the major axis is almost equivalent to bending it simultaneously in the plane of major and minor axes with bending radii /spl rho/sec/spl theta/ and /spl rho/cosec/spl theta/, respectively. The bending-induced phase difference between the two modes is found (a) to be maximum when the waveguide is bent along the major axis, and (b) to decrease first and then increase in the opposite direction as the V-number is decreased. The results of our study can be used to improve the sensitivity of the dual-mode optical waveguide sensors and devices based on the bending of fiber.

On the zero bending-induced phase shift in a dual-mode rectangular / elliptical core waveguide

Abstract Using the recently developed analysis for an arbitrarily bent dual-mode rectangular core waveguide (RCW), we investigate here the conditions under which the bending induced phase shift in such waveguides is zero. It is found that waveguides with sufficiently large V-values when bent in a certain plane (at an angle θ0 with respect to the major axis) exhibit no bending-induced phase shift. The variation in the value of θ0 and the variation in the phase shift around θ0 with various waveguide parameters are studied in detail. The study should be useful in designing bending-insensitive dual mode e-core fiber sensors.