Experimental demonstration of single-shot quantum and classical signal transmission on single wavelength optical pulse

Rupesh Kumar, Adrian Wonfor, Richard Penty, Tim Spiller, Ian White

OAI: oai:www.repository.cam.ac.uk:1810/308635 • DOI: 10.17863/CAM.55723

Abstract: Advances in highly sensitive detection techniques for classical coherent communication systems have reduced the received signal power requirements to a few photons per bit. At this level one can take advantage of the quantum noise to create secure communication, using continuous variable quantum key distribution (CV-QKD). In this work therefore we embed CV-QKD signals within classical signals and transmit classical data and secure keys simultaneously over 25 km of optical fibre. This is achieved by using a novel coherent displacement state generator, which has the potential for being used in a wide range of quantum optical experiments. This approach removes the need for separate channels for quantum communication systems and allows reduced system bandwidth for a given communications specification. This demonstration therefore demonstrates a way of implementing direct quantum physical layer security within a conventional classical communications system, offering a major advance in term of practical and low cost implementation.

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