Optimization of heterogeneously integrated InP-Si on-chip photonic components

TL;DR

This paper presents numerical analysis of a hybrid InP/Si photonic platform with embedded quantum dots, achieving high coupling efficiency and broadband operation suitable for integrated quantum photonics.

Contribution

It introduces a numerically optimized hybrid InP/Si waveguide system with embedded quantum dots, demonstrating high coupling efficiency and broadband operation for quantum photonic integration.

Findings

86% optical field transfer efficiency between InP/Si and Si waveguides

~60% coupling efficiency of quantum dot emission to hybrid waveguide

Up to 26% off-chip outcoupling efficiency with circular Bragg grating

Abstract

We demonstrate comprehensive numerical studies on a hybrid III-V/Si-based waveguide system, serving as a platform for efficient light coupling between an integrated III-V quantum dot emitter to an on-chip quantum photonic integrated circuit defined on a silicon substrate. We propose a platform consisting of a hybrid InP/Si waveguide and an InP-embedded InAs quantum dot, emitting at the telecom C-band near 1550 nm. The platform can be fabricated using the existing semiconductor processing technologies. Our numerical studies reveal nearly 86% of the optical field transfer efficiency between geometrically-optimized InP/Si and Si waveguides, considering propagating field modes along a tapered geometry. The coupling efficiency of a dipole emitting to the hybrid InP/Si waveguide is evaluated to ~60%, which results in more than 50% of the total on-chip optical field transfer efficiency from the dipole to the Si waveguide. We also consider the off-chip outcoupling efficiency of the propagating photon field along the Si waveguide by examining the normal to the chip plane and in-plain outcoupling configurations. In the former case, the outcoupling amounts to ~26% when using the circular Bragg grating outcoupler design. In the latter case, the efficiency reaches up to 10%. Finally, we conclude that the conceptual device's performance is weakly susceptible to the transferred photon wavelength, offering a broadband operation within the 1.5-1.6 {\mu}m spectral range.