Correction to the Effective Refractive Index and the Confinement Factor in Waveguide Modeling for Quantum Cascade Lasers

TL;DR

This paper refines the calculation of the effective refractive index and confinement factor in quantum cascade laser waveguides by incorporating anisotropic gain and non-Hermitian effects, leading to more accurate modeling.

Contribution

It introduces a rigorous perturbation theory approach that corrects previous equations for waveguide parameters in quantum cascade lasers, accounting for anisotropic and non-Hermitian properties.

Findings

A few percent correction to confinement factor and effective gain.

Generalization of the correction method to layered optical devices.

Enhanced accuracy in waveguide modeling for quantum cascade lasers.

Abstract

The equations for the effective medium refractive index and for the confinement factor in the waveguide design for quantum cascade lasers are derived.Compared to equations used in prior literature, by applying rigorous perturbation theory and including the effect of the anisotropic optical gain and non-Hermitian properties of the waveguide structure and materials, a few percent correction should be made to the confinement factor and the effective gain. This result can easily be generalized to any optical devices with a layered structure.