Characterisation of Laser sources used for optimisation of single-photon detection

Abstract

This thesis focuses on the development and characterisation of a Weak Coherent Pulse (WCP)source operating at the 1550 nm telecommunication wavelength, which acts as the baseline for the single-photon emitter that can be utilised in the characterisation of the Superconducting Nanowire Single Photon Detector (SNSPD). While ideal quantum com munication and the ultimate goal of this project are deterministic single-photon sources, this work focuses on establishing the necessary experimental control over the laser source through attenuation and high-speed temporal modulation. The experimental methodology involves the precise characterisation of a stabilised fi bre laser by attenuation of the input and implementing high-speed temporal modulation. To reduce the number of photons in a pulse and attain the desired photon statistics, we go on reducing the pulse width and optical power. The resulting WCP source remains in the classical regime yet provides the neces sary precision to evaluate critical detector parameters, such as detection efficiency and timing jitter. Ultimately, this work remains a small contribution to the advancement of experimental quantum optics and provides a reliable framework for future quantum communication studies.