GaSb-based Quantum Dots for Quantum Photonic Integration

Abstract

Quantum dots (QDs) are nanoscale crystals showing unique optical properties due to quantum confinement effects and discrete energy levels, making them a promising candidate as the source for single and entangled photons for the advancing quantum photonic applications. One of the challenges that is faced during the photonic integration is to couple the photons from the photonic chip platform generated by the QDs to optical fiber with low loss. A grating coupler is introduced as a highly practical solution for the photon coupling process. The primary focus of thesis is the design of the grating coupler for the integration of GaSb-based QDs using Lumerical FDTD simulations. The design procedure focuses to optimize the geometry to maximize the extraction efficiency for the QD emission at 1.5 µm while simultaneously allowing injection of the excitation laser operating at the wavelength of 1.45 µm. The presented design demonstrates a high coupling efficiency that underscores the potential of grating couplers for quantum integrated photonics applications.