Analysis of Parabolically versus Exponentially Tapered Inbuilt Chip-to-Fiber Butt Coupler

Abstract

The finite difference beam propagating method (BPM) is one of the most powerful technique to investigate linear and nonlinear lightwave propagation phenomena in axially varying waveguides such as curvilinear directional couplers, branching and combining waveguides, S-shaped bend waveguides, and different types of tapered waveguides. BPM is also quite important for the analysis of ultra short light pulse propagation in optical fibers. To date numerous algorithms for BPM have been proposed and successfully applied to a very wide class of dielectric optical waveguide structures. A parabolically and an exponentially tapered structure is introduced into the chip-to-fiber butt coupler. The butt couplers are fabricated with the InP - InGaAsP waveguide. In this paper, a comparison is being carried out between the both proposed structure and it is observed from our study, that there is a more substantial loss in parabolically tapered structure as compared to the exponentially tapered structure. The working principle of parabolically tapered structure is similar to that of exponentially tapered structure, so authors can substitute parabolically tapered structure with exponentially tapered one. During the course end of this paper, the excess loss of the proposed structure is compared.