Quantum Information Processing by Programming Optical Nano-Circuits in Silicon

  • Dan M Llewellyn

Student thesis: Doctoral ThesisDoctor of Philosophy (PhD)


Quantum technologies, able to manipulate the individual quantum states of single particles, have the potential to revolutionise science and engineering. The possible applications of these technologies are remarkably broad, ranging from the simulation of the underlying physics that governs our universe, to securing the worlds information, and even to improving health-care through quantum metrology. Though there are many competing quantum technology platforms, quantum platforms based on light are uniquely fascinating due to their low noise and suitability for communications. Modern fabrication methods allow for the production of chip-scale devices that can trap and manipulate single particles of light (photons) to produce complex quantum states on chip. In particular, silicon photonic devices are of interest due to the abundance and supply chains of silicon in the microelectronics industry. Theoretically, these supply chains could be leveraged to mass produce high performance quantum technologies built from silicon photonic components at scale and low cost.

In this thesis we explore current silicon quantum photonic technologies and their applications. In particular, we asses how they can be leveraged to generate pure single photons and how multiple photons can be reliably interfered on a chip. In addition, we introduce many key integrated quantum optic components and explain how, when combined with high quality single photon sources, they can be used to encode quantum information in silicon chips. Several of the fundamental protocols of quantum information theory are benchmarked on state-of-the-art silicon photonic chips and methods for chip-to-chip demonstrations are proposed and verified. Finally, we discuss the scalability of these devices and outline the technologies that are required in order to advance the field of integrated quantum photonic technologies.
Date of Award26 Nov 2020
Original languageEnglish
Awarding Institution
  • The University of Bristol
SupervisorJohn G Rarity (Supervisor) & Mark Thompson (Supervisor)


  • quantum communication
  • quantum computing
  • quantum information
  • Quantum Photonics
  • quantum key distribution
  • quantum optics
  • silicon photonics
  • photonics

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