Coupled-waveguides for dispersion compensation in semiconductor lasers

TL;DR

This paper introduces a dual waveguide design for intracavity dispersion compensation in semiconductor lasers, enabling stable frequency comb generation in mid-infrared quantum cascade lasers and potentially across various wavelengths.

Contribution

A novel dual waveguide approach for intracavity dispersion compensation in semiconductor lasers, applicable to multiple material systems and wavelength ranges.

Findings

Achieved stable comb operation in a mid-infrared quantum cascade laser.

Demonstrated the dual waveguide's applicability to various semiconductor laser types.

Enabled efficient dispersion compensation at near-infrared wavelengths.

Abstract

The generation of optical frequency combs via direct electrical pumping of semiconductor lasers is an attractive alternative to the well-established mode-locked laser sources in terms of compactness, robustness and integrability. However, the high chromatic dispersion of bulk semiconductor materials can prevent the generation of frequency combs or lead to undesired pulse lengthening. In this letter, we present a novel dual waveguide for intracavity dispersion compensation in semiconductor lasers. We apply the concept to a short mid-infrared wavelength quantum cascade laser operating in the first atmospheric window (\lambda $ \approx$ 4.6 \mu m). As a result, stable comb operation on the full dynamical range is achieved in this device. Unlike previously proposed schemes, the dual waveguide approach can be applied to various types of semiconductor lasers and material systems. In particular, it could enable efficient group velocity dispersion compensation at near-infrared wavelengths where semiconductor materials exhibit a large value of that parameter.