Thesis

Deep ultraviolet light-emitting diodes for high-speed optical communications

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Awarding institution
  • University of Strathclyde
Date of award
  • 2026
Thesis identifier
  • T18095
Person Identifier (Local)
  • 201975229
Qualification Level
Qualification Name
Department, School or Faculty
Abstract
  • Micro-light-emitting diodes (μLEDs), defined as LEDs with dimensions below 100 μm, are at the forefront of innovation, including for deep ultraviolet (DUV) emission. The rapid advances in μLED technology have unlocked new potentials for applications in high-resolution displays and, notably, optical wireless communications. This thesis presents a thorough characterisation of DUV μLEDs and explores their implementation in wireless communication systems. Through a series of in-depth experiments, this research noted pronounced size-dependent behaviours in μLEDs, including variations in turn-on voltage, optical output power, quantum efficiency, and modulation bandwidth. Smaller devices were found to require higher turn-on voltages and lower efficiencies but higher bandwidths. These observations demonstrated the necessity for continued research into contact technologies and the fundamentals of device operation for DUV μLEDs. Pushing the boundaries of optical wireless communication, this work demonstrates key advances in wavelength-division multiplexing (WDM) for the ultraviolet spectrum. Notably, the first three-wavelength UV communication system is showcased, achieving a combined data throughput of nearly 10 Gbps, one of the highest reported in the UV regime. While the performance of UVB-emitting devices used here lagged behind that of the other wavelengths, this provides a clear trajectory for future refinement. Furthermore, this thesis reports on the development of medium-range, line-of-sight DUV μLED communication links, achieving data rates up to 1 Gbps over unprecedented distances of 100 metres. This stands as the highest data rate attained over such a range using a single μLED pixel at any wavelength at the time of writing. The capabilities of μLEDs were further explored through a two-mirror system, enabling multi-reflection transmission and achieving significant data rates over short distances (less than 10 metres). The research also investigates non-line-of-sight (NLOS) communication using commercially available DUV LEDs. These experiments demonstrate a robust kilobits per-second link, benefiting from the milliwatt-level optical power of current DUV commercial devices. The integration of novel, single-photon-sensitive DUV detectors facilitated NLOS links, including around-corner communication, opening promising new directions for ultraviolet optical wireless technology. In summary, this thesis delivers insights into the size-dependent phenomena of DUV μLEDs, establishes their promise for high-speed optical wireless communication, and showcases both line-of-sight and non-line-of-sight data transmission. Collectively, these findings advance the field of ultraviolet optoelectronics and lay the groundwork for future innovation in μLED-based communication technologies.
Advisor / supervisor
  • Dawson, Martin
  • Herrnsdorf, Johannes
Resource Type
DOI
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