Uncovering dispersion properties in semiconductor waveguides to study photon-pair generation

TL;DR

This paper studies the dispersion properties of semiconductor waveguides to understand their phase-matching for photon-pair generation, providing a practical method to optimize broadband parametric down-conversion sources.

Contribution

It introduces a straightforward approach to determine phase-matching and dispersion characteristics of waveguides using Fabry-Perot experiments and PDC spectra analysis.

Findings

Determined group refractive indices via Fabry-Perot measurements.

Analyzed PDC photon spectra to access group index dispersion.

Provided a method to estimate PDC bandwidth and design broadband sources.

Abstract

We investigate the dispersion properties of ridge Bragg-reflection waveguides to deduce their phasematching characteristics. These are crucial for exploiting them as sources of parametric down-conversion (PDC). In order to estimate the phasematching bandwidth we first determine the group refractive indices of the interacting modes via Fabry-Perot experiments in two distant wavelength regions. Second, by measuring the spectra of the emitted PDC photons we gain access to their group index dispersion. Our results offer a simple approach for determining the PDC process parameters in the spectral domain and provide an important feedback for designing such sources, especially in the broadband case.