Wavelength flattened directional couplers: a geometrical approach

TL;DR

This paper introduces a geometrical method using operator theory and a Poincare sphere representation to design wavelength-insensitive optical power splitters, providing clearer insights and improved solutions.

Contribution

It presents a novel geometrical approach to designing wavelength-insensitive couplers using operatorial form and Poincare sphere visualization.

Findings

Graphical tool clarifies previous results

Method enables improved coupler designs

Provides intuitive understanding of wavelength insensitivity

Abstract

A new approach to design wavelength insensitive optical power splitter is presented. First coupled-mode theory is cast in operatorial form. This allows to solve the equivalent of coupled differential equations as simple limits. The operators are then represented on a generalized Poincare sphere, and the resulting graphical tool is applied to different structures, giving a clear interpretation of previous results in literature as well as hints on how to find improved solutions.