John G. Rarity is a British physicist who is professor of optical communication systems in the department of electrical and electronic engineering at the University of Bristol, a post he has held since 1 January 2003.

[2][3] Rarity was educated at the University of Sheffield (BSc)[4] and awarded a PhD from the Royal Military College of Science in 1984 for research on spectroscopy applied to coagulating dispersions.

[6] A collaboration with Ludwig-Maximilian University, Munich in 2002 successfully demonstrated an open air quantum cryptography experiment over a distance of 23.4 km.

[8] In 2007 Rarity collaborated in a demonstration of quantum key distribution using free space optical communications over 144 km[9] between the islands of Tenerife and La Palma.

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