This PhD project, based at the University of Southampton within the EPSRC Centre for Doctoral Training in Quantum Technology Engineering, explores the use of hollow core optical fibres to enable quantum communications. Traditional optical fibres are limited in their ability to transport quantum states, such as qubits or entangled photons, especially at wavelengths where quantum sources and detectors operate. Hollow-core fibres, pioneered at Southampton, guide light through a central hole surrounded by a special glass structure, allowing for lower attenuation and compatibility with both quantum and classical signals. The project aims to exploit these fibres to create a universal transmission medium capable of supporting quantum signals (700-1000 nm) and classical telecom signals (1530-1610 nm) simultaneously. The Optoelectronics Research Centre (ORC) at Southampton, led by Prof. Francesco Poletti, is a world leader in the design and manufacturing of these fibres. Collaboration with leading quantum physics groups, such as the University of Vienna, and support from Microsoft Azure (which acquired the ORC spin-off manufacturing the fibres) will enable the demonstration of new quantum communication approaches. The position offers substantial training in scientific, technical, and commercial skills, and is supported by a competitive UKRI TechExpert stipend of around £31k per year for UK students, with funding also available for EU, Horizon Europe, and international students. Applicants should have at least a UK 2:1 honours degree or international equivalent, and submit a CV, two academic references, degree transcripts/certificates, and English language qualification if applicable. The university is committed to equality, diversity, and sustainability, and supports part-time study. The application deadline is 31 July 2026, with an earlier deadline of 31 March 2026 for international applicants.