Candidate: Nigar Sultana
Title: Single-photon Detectors for Satellite-Based Quantum Communications
Date: November 22, 2019
Place: RAC1 2009
Supervisor(s): Miao, Guo-Xing - Jennewein, Thomas (Quantum Computing)
With the growing use of online communications in our modern society, information security is becoming a big concern. Along with that, the progress in quantum computers is posing severe threats to such communications. Once powerful quantum computers become available, most of today's encryption schemes will be broken within a short period. Researchers are therefore making a great effort to establish quantum-safe encryption schemes. One such scheme is quantum key distribution (QKD), which utilizes the laws of quantum mechanics. These cryptography protocols offer unconditional security to the communication between two distant parties by providing a secure way of sharing encryption keys between them. However, there are many aspects of QKD that need further evaluation and advancement for establishing long-term satellite-based quantum communication (QC). My research works were a contribution to the development of systems for single-photon detectors and quantum sources, which are key elements of QC. In this talk, I will briefly discuss the development of a miniaturized single-photon detector system for a cube satellite that incorporates facilities for laser and thermal annealing to mitigate in-orbit radiation damage of the silicon single-photon avalanche photodiodes (SPADs). Then I will provide an overview of a new readout module implemented for negative feedback avalanche photodiodes (InGaAs/InP SPADs) and a high-speed weak coherent pulsed source that I have worked on during my PhD.
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