Design of a silicon photonics circuit for quantum cryptography applications

Quantum Key Distribution (QKD) offers information-theoretic security based on the principles of quantum mechanics, representing a promising solution to the vulnerabilities of classical cryptographic protocols against advancing computational capabilities. To enable widespread deployment of QKD systems, a scalable, stable, and cost-effective platform is essential. In this context, silicon photonics emerges as a strong candidate, providing CMOS compatibility, high integration density, and mature fabrication processes. This thesis explores the design, fabrication, and experimental validation of an integrated QKD transmitter implemented in a silicon-on-insulator (SOI) platform.The work begins with an introduction to QKD and integrated photonics, reviewing the theoretical principles and technological motivations behind their combined implementation. Based on the chosen protocol, the required components for an integrated transmitter are identified and studied in detail.