Rare-earth doped optical fibers are widely used in lasers, telecommunications, and sensing. However, their performance is often limited by the glass matrix, especially at high dopant concentrations. In her dissertation, Natalia Vakula explores new composite materials where rare-earth doped crystals are embedded directly into glass to overcome these limitations.
Natalia Vakula developed and tested different types of Yb³⁺ doped materials using phosphate, tellurite, and silica-based glasses. She combined glass-ceramic and composite approaches to integrate Yb³⁺ doped crystals into the glass matrix.
“My study demonstrated that these crystals could survive high-temperature processing and be used to produce glass preforms and even draw optical fibers. By embedding crystalline phases into glass, I aimed to combine the advantages of both materials: the optical performance of crystals and the versatility of glass,” Vakula says.
Her doctoral dissertation also explored how these new materials behave under proton irradiation, showing that they retain their structure and emission, making them promising candidates for optical systems in space and other radiation-rich environments.
Natalia Vakula’s research provides new insight into how glass-crystal composites can be used in advanced photonics, especially where high emission efficiency and radiation tolerance are required.
Natalia Vakula is originally from Chelyabinsk, Russia. She conducted her doctoral research at Tampere University, Finland.
Public defence on Monday 8 September
The doctoral dissertation of MSc Natalia Vakula in the field of physics titled Development of Novel Yb³⁺ Doped Glass-Based Materials for Advanced Optical Fibers will be publicly examined at the Faculty of Engineering and Natural Sciences at Tampere University at 14:00 on Monday, 8 September 2025 via ZOOM.
The Opponent will be Professor John Ballato from Clemson University, South Carolina, USA. The Custos will be Professor Laeticia Petit from Tampere University, Finland.
The doctoral dissertation is available online.
The public defence can be followed via remote connection.