PhD defence by Aditi Mehta

Abstract

With the growing demand for faster internet and more data, today’s communication systems need better optical fibers— the tiny glass threads that carry light signals worldwide. My PhD research focused on developing a new type of optical fiber that can carry more information at once and handle higher power safely. This new fiber design has two special cores arranged in a ring shape and air gaps inside the structure. These features help guide advanced light patterns, known as orbital angular momentum (OAM) modes, which allow more data to travel through a single fiber. The air gaps also help reduce unwanted mixing between signals in the two cores, keeping the data clean and separate. Another essential part of my research studied a dangerous effect called “fiber fuse,” where too much light can cause the fiber to burn from the inside. I tested how this happens in multi-core fibers and found ways to make the fibers more resistant— especially by using designs with air gaps. This work can help improve the speed, safety, and capacity of future communication systems used in internet networks, data centers, and high-power laser applications.

Supervisors

• Principal supervisor: Professor Toshio Morioka, Department of Electrical and Photonics Engineering, DTU, Denmark
• Co-supervisor: Professor Karsten Rottwitt, Department of Electrical and Photonics Engineering, DTU, Denmark

Evaluation Board

• Senior Researcher Lars René Lindvold, Department of Electrical and Photonics Engineering, DTU, Denmark

• Senior Researcher Fellow Hans Christian Mulvad, University of Southampton, Optoelectronics Research Centre, United Kingdom

• Assistant Director General Shu Namiki, National Institute of Advanced Industrial Science and Technology (AIST), Japan

Master of the Ceremony

• Professor Leif Katsuo Oxenløwe, Department of Electrical and Photonics Engineering, DTU, Denmark