Title: Advanced laser technology for quantum communications

Abstract

In this new decade our societies will face rapid changes and will need to adapt to a wide range of new technologies emerging from the quantum world. Among them, quantum communications is set to occupy a central place in our future ways of exchanging and processing of information: by exploiting the laws of quantum mechanics, it allows transferring and manipulating information beyond the capabilities of our conventional technologies. Owing to the threat of quantum computers against conventional public key cryptography algorithms methods, quantum key distribution (QKD) arose as means to establish symmetric encryption keys between distant parties, with information theoretic security. In the recent years, QKD has demonstrated a high level of maturity, which motivated governments and industry partners to work towards the development of large-scale quantum communication infrastructures. This perspective poses an immediate practicality challenge: how to encode quantum information in a versatile way while preserving the constraints of low-cost production, high power efficiency, small size and high scalability required for a viable integration in our conventional communication infrastructure? In this talk, we present recent advances in laser modulation technologies that have enabled the development of efficient and versatile light sources for quantum communications. Based-on on appropriate combinations of different features of well-known laser physics, these sources have been used to demonstrate several QKD protocols with state-of-the-art performance. After introducing the concepts of quantum cryptography and advanced laser modulation techniques, we review and interpret the applications and experimental results enabled by this new approach in the light of a complete theoretical framework.