A transmitter for a quantum communication system, a quantum communication system and a method of generating intensity modulated Photon pulses

摘要

A transmitter for a quantum communication system has a photon source unit 1 comprising a photon source. The photon source unit may be configured to emit light pulses having a first intensity and a second intensity. A first intensity modulator is configured to receive an input light pulse from the photon source unit. The first intensity modulator comprises a first element 2 which is configured to split the input light pulse into two components, a phase modulator 3 configured to apply a phase shift between the two components, and a second element 4 configured to interfere the two components. The first intensity modulator may output light pulses having three or more different intensities. At least one of the first element and the second element are asymmetric. The first or second elements may comprise an asymmetric beam splitter, a tuneable ratio splitter or a polarising beam splitter. The transmitter may be configured to implement decoy state quantum communication.