1 GHz and counting
Helen Dyball · Electronics Letters · 2012
A 1 gigacount/second single photon detector has been built by UK-based researchers at Toshiba in collaboration with the Cambridge University Engineering Department. By developing a ‘self-differencing’ circuit for use with a thermoelectrically cooled semiconductor avalanche photodiode (APD) they have achieved the highest count rate among any single photon detectors.“We are developing quantum key distribution (QKD) to protect future communication networks,” said Dr Zhiliang Yuan from the Quantum Information Group at Toshiba Research Europe Ltd. “This technology is advantageous because its security is guaranteed by quantum mechanics. However, it also poses technical challenges, one of which is high-performance single photon detectors.“So far, our self-differencing APDs have allowed the QKD secure key rate to break the 1 Mbit/s barrier for the first time. As a practical device they have withstood rigorous tests in the field environment in the 2010 Tokyo QKD network.”