Applied Physics Letters
Efficient quantum key distribution with stable and expansible differential phase shift schemes
Xiuliang Chen, Chunyuan Zhou, Guang Wu, Heping Zeng
Abstract
Efficient quantum key distribution can be achieved by using a stable differential phase shift scheme, with an expansible setup mainly composed of several parallel Mach–Zehnder interferometers, a serial Mach–Zehnder interferometer, and a Faraday mirror. An expansion of the scheme by adding more parallel Mach–Zehnder interferometers can conveniently increase the key creation efficiencies, and the energies of the interfering pulses can be equalized easily without changing the phase shifts in the serial interferometer. The long-term stabilities are guaranteed by using a multifeedback servo-system and Faraday mirror. And the sensibilities of the scheme to the disturbance of eavesdropping are improved by increasing the key creation efficiencies. The security of the scheme against some possible attacks, such as intercept/resend attack and Trojan horse attack, are discussed.