Unlike conventional quantum key distribution (QKD), high-dimensional QKD allows encoding onto a larger state space, such as multiple levels of a continuous variable of a single photon, thus enabling higher photon information efficiency (bits per photon) and potentially higher key rate (bits per second). This thesis focuses on the implementation of a time-energy entanglement-based QKD system, with the development of several enabling technologies including a single-spatial-mode source of entangled photons based on a periodically-poled KTiOPO4 (PPKTP) waveguide, and the demonstration of a non-locally dispersion-cancelled Franson quantum interferometry achieving 99.6% visibility. We utilize these technologies to perform full QKD protocols that deploy two different source configurations. We have achieved a secure key rate ~7 Mbits/s with 2.9 bits/photon after error-correction and privacy amplification, which represents the state-of-the-art in today’s QKD technology.
Thesis Supervisor: Dr. Franco Wong