Abstract
Today, we live in a digital age where our everyday life relies on the secure transmission of vast amounts of valuable data, including private messages, credit card payments and medical information. However, with the rise of the quantum computer the traditionally employed asymmetric cryptography algorithms, based on complex mathematical problems, are deemed
unsafe. In response, quantum key distribution (QKD), relying on the fundamental laws of quantum physics, has been developed. Although first real-world QKD deployments are underway, a diverse set of challenges, associated with the QKD system size and cost as well as the co-existence of quantum/classical signals, need to be addressed to enable the widespread deployment of QKD.
In response, this thesis takes a similarly diverse approach: Starting from simplified optical quantum random number generators it continues to investigate the potential application fields of continuous-variable QKD in today’s optical telecommunication networks. In the following, record-high classical/quantum co-propagation powers in hollow-core fibers are demonstrated. Subsequently, the generation of polarization-encoded photons for discrete-variable QKD via multi-purpose quantum/classical optics is shown. Nonetheless, to reduce the size and cost, the photonic integration of QKD is paramount. To this end, the first fully-monolithic QKD transmitter
for polarization-encoded photon generation realized on silicon is presented. This achievement paves the way towards seamlessly co-integrated opto-electronic QKD transmitters for commodity applications, where a small form-factor is paramount. Finally, this thesis concludes with an investigation of simplified short-range free-space optical communication link architectures as a
popular alternative to fiber-based optical links. As a result, this thesis aims to provide solutions to some of the diverse challenges faced by QKD, in order to propel its widespread deployment in fiber and free-space optical networks by virtue of simplified architectures, multi-purpose optics and
photonic integration. And maybe one day, whenever we pay with our mobile phones or access our data online, we all use quantum secured optical links.
unsafe. In response, quantum key distribution (QKD), relying on the fundamental laws of quantum physics, has been developed. Although first real-world QKD deployments are underway, a diverse set of challenges, associated with the QKD system size and cost as well as the co-existence of quantum/classical signals, need to be addressed to enable the widespread deployment of QKD.
In response, this thesis takes a similarly diverse approach: Starting from simplified optical quantum random number generators it continues to investigate the potential application fields of continuous-variable QKD in today’s optical telecommunication networks. In the following, record-high classical/quantum co-propagation powers in hollow-core fibers are demonstrated. Subsequently, the generation of polarization-encoded photons for discrete-variable QKD via multi-purpose quantum/classical optics is shown. Nonetheless, to reduce the size and cost, the photonic integration of QKD is paramount. To this end, the first fully-monolithic QKD transmitter
for polarization-encoded photon generation realized on silicon is presented. This achievement paves the way towards seamlessly co-integrated opto-electronic QKD transmitters for commodity applications, where a small form-factor is paramount. Finally, this thesis concludes with an investigation of simplified short-range free-space optical communication link architectures as a
popular alternative to fiber-based optical links. As a result, this thesis aims to provide solutions to some of the diverse challenges faced by QKD, in order to propel its widespread deployment in fiber and free-space optical networks by virtue of simplified architectures, multi-purpose optics and
photonic integration. And maybe one day, whenever we pay with our mobile phones or access our data online, we all use quantum secured optical links.
| Originalsprache | Englisch |
|---|---|
| Qualifikation | Doktor / PhD |
| Gradverleihende Hochschule |
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| Betreuer/-in / Berater/-in |
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| Datum der Bewilligung | 16 Dez. 2025 |
| Publikationsstatus | Veröffentlicht - 2025 |
Research Field
- Ehemaliges Research Field - Enabling Digital Technologies