Article ID Journal Published Year Pages File Type
1536989 Optics Communications 2011 4 Pages PDF
Abstract

Differential-phase-shift (DPS) quantum key distribution (QKD) is one of the QKD protocols, featuring simplicity for practical implementation. It uses a coherent pulse train whose phase should be stable at least within the pulse interval. This paper quantitatively investigates the phase stability required for DPS-QKD systems. The phase stability is characterized by the spectral linewidth of the light source. A theoretical model and experiments are presented, the results of which indicate that the linewidth should be, for example, less than 0.35% of the free-spectral-range of an asymmetric Mach–Zehnder interferometer in a receiver to achieve quantum bit error rate of less than 0.5% due to linewidth broadening of the light source.

Related Topics
Physical Sciences and Engineering Materials Science Electronic, Optical and Magnetic Materials
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