Modal Method Analysis of Quantum-Dot Nanowires for Single Photon Sources

Within optical quantum information processing, the quantum bits are encoded on single photons, and a key component is thus a source capable of producing single indistinguishable photons on demand. However, designing a single-photon source combining simultaneously photon purity and indistinguishability with high extraction efficiency remains a challenge [1]. Nanowires with embedding semiconductor quantum dots have recently emerged as an attractive platform [1] for deterministic single-photon generation. For design purposes, the efficient simulation of a quantum-dot nanowire system is required. One of the most efficient and convenient approaches is the modal method as it can exploit symmetry properties of the structure and provides insight into the physical behavior of a system such as propagation constants of the modes and modal scattering coefficients [2]. In this contribution, the coupling problem of a quantum dot and a dielectric nanowire is modelled and efficiently simulated using a full vectorial modal method employing open boundaries to avoid spurious reflections [3]. Therefore, matched or absorbing layers are not required. In addition to conventional circular structures, elliptical structures, which can supply a true monomode and allow controlling the polarization [4], are analyzed.