Photonic quantum processors based on integrated quantum photonic circuits require entangled photon pairs to perform quantum computations. However, current state-of-the-art technologies utilize probabilistic entangled photon sources with limited pair-extraction efficiencies, negatively affecting the computation speed. This project aims to boost the speed of on-chip quantum operations by using bright, on-demand entangled photon sources with an extraction efficiency of more than two orders of magnitude higher than the existing state-of-the-art technology based on probabilistic photon sources. Our novel photon source will be developed by embedding quantum dots in tapered nanowire waveguides and surrounding them with a microcavity that accommodates entangled photons. This setup will produce bright, highly entangled photon pairs at a specified rate in a well-defined time interval, with high single-photon purity, pair extraction efficiency, photon indistinguishability, and entanglement fidelity. The tapered geometry of the nanowire allows for simple and efficient coupling of the produced photons into a low-loss optical fibre. This will enable the quantum dot sources to operate in a low-temperature cryostat, while the integrated photonic circuits operate at room temperature. Through fibre optic cables, the photons will be inserted into the integrated photonic circuit using custom-designed components such as grating couplers and edge couplers. This modular approach will be used to implement a vital protocol known as entanglement swapping, which is critical for large-scale quantum computing. Two core operations, a Bell-state measurement and quantum state tomography, will be performed by the integrated photonic circuits. The result of the procedure will be that two remote integrated photonic circuits will share entanglement. This novel quantum light source technology combined with integrated quantum photonic circuits will boost the speed, efficiency, and scalability of quantum operations compared to the current state-of-the-art system. Thus, this project will develop critical components of quantum photonic technologies that can pave the way for more secure communication, increase computation speed for complex problems, and enable a large-scale photonic quantum processor to be built in Canada.
Figure 1. Illustration of the proposed experimental system for interfacing entangled photons emitted by the nanowire quantum dot sources with photonic integrated circuits for implementing quantum computing tasks on-chip. The emission from multiple entangled photon sources based on nanowire quantum dots that sit at low temperatures will be coupled to single-mode fibres. Using grating couplers, the entangled photons will be coupled into the photonic circuit for processing and then coupled out for detection.
Tuning Spin-Exchange Interactions in Low-Dimensional Metal Halide Perovskites: A New Class of Semiconductor Quantum Materials
Summary Leakage current in electronic components is one of the limiting factors for the performance of conventional computers which use charges and currents as physical information carriers. Spintronics offers an alternative by using electron spin for information transfer, processing and storage, enabling the design of non-volatile computer memory and more energy-efficient electronic devices. In this […]
October 1, 2019
Functionalized Nanodiamonds for Sensing Biochemical Processes
Summary Chemotherapy is limited by the failure to clinically monitor the efficacy of the treatment in real-time, which results in suboptimal chemotherapy being given for a prolonged period. Predicting the outcome of chemotherapy immediately after drug administration can increase diagnostic accuracy, efficacy outcomes, and successful treatment. Quantum nanodiamond sensors can be used as optical sensors […]
August 31, 2022
Line-Scanning optical coherence tomography system for in-vivo, non-invasive imaging of the cellular structure and blood perfusion of biological tissue
Summary Optical coherence tomography (OCT) is an optical imaging method that allows for in-vivo, non-invasive imaging of the structure and vasculature of biological tissue. Commercially available, clinical OCT systems utilize point-scanning method to acquire volumetric images over a large surface with typical frame rates of ~ 30 frames/ second. Since living biological tissue is constantly […]
August 27, 2019
A Reformulation of Quantum Game Theory
Summary Classical game theory – conducted at the interface between economics and computer science – has found applications in topics ranging from networking and security to online markets. Despite over 20 years of research into connections between game theory and quantum information, we have yet to see any significant implications of quantum information when applied […]
April 1, 2020