PhD defence by Alif Laila Muthali

Abstract

Quantum technologies have the potential to revolutionize how we process information, going beyond the capabilities of today's classical systems. While classical computers handle information in a straightforward way, quantum systems can solve complex problems much faster by using the unique properties of quantum physics. However, building these advanced quantum systems requires new breakthroughs in how we design and use photonic devices.

This research takes a significant step forward by developing cutting-edge photonic components that will help make quantum technologies a reality. By working with two promising materials—Silicon (Si), which is widely used in computer chips, and Lithium Niobate on Insulator (LNOI), which is excellent for controlling light—the research creates components that are both powerful and scalable for future quantum systems.

The work on Si focuses on making energy-efficient devices that help control and guide light, which is essential for building large quantum photonic devices. A key outcome of this research is the successful demonstration of a quantum application using a photonic chip. This demonstrates the potential to simulate quantum phenomena beyond the capabilities of classical computers, advancing quantum problem-solving. On the other hand, the research on LNOI contributes to the development of high-speed switches that allow quantum signals to be processed and routed quickly and with minimal loss, ensuring the accuracy needed for quantum communication and computing.

Together, these innovations lay the groundwork for quantum chips and circuits that could be used in a variety of future applications, from superfast computing to ultra-secure communication. This thesis highlights the critical role photonics will play in transforming quantum technology from theory to real-world systems that can outperform classical methods.

Supervisors

• Principal supervisor: Senior Researcher Yunhong Ding, Department of Electrical and Photonics Engineering, DTU, Denmark
• Co-supervisor: Professor Kresten Yvind, Department of Electrical and Photonics Engineering, DTU, Denmark

Evaluation Board

• Senior Researcher Minhao Pu, Department of Electrical and Photonics Engineering, DTU, Denmark
• Associate Professor Leonardo Midolo, Niels Bohr Institute, University of Copenhagen, Denmark
• Associate Professor Ali Elshaari, KTH Royal Institute of Technology, Sweden

Master of the Ceremony

• Professor Darko Zibar, Department of Electrical and Photonics Engineering, DTU, Denmark