Kabushiki Kaisha Toshiba

Bernd Matthias Frohlich

Andrew James Shields

Zhiliang Yuan

Marco Lucamarini

James Dynes

Joanna Krystyna Skiba-Szymanska

A communication system comprising n transmitters and a receiver, where n is an integer of at least 2, each of said n transmitters comprising a light source and an encoder such that each transmitter is adapted to output an encoded pulse of light, said receiver comprising a first element, the system further comprising a timing circuit, the timing circuit being configured to synchronize the encoded pulses output by the transmitters such that interference between a light pulse sent from the first transmitter and a light pulse from the second transmitter, interfere at the first element, each transmitter further comprising a suppressing element adapted to stop light exiting one of the transmitters such that the system is switchable between a first operation mode where two transmitters output encoded pulses and where both pulses interfere at the interference element and a second mode of operation where just one transmitter transmits light pulses to said receiver, the suppressing element being controlled to stop light exiting the other transmitter.

Multi-transmitter quantum optical communication system and method

In a quantum communication system, each transmitter unit has a source of quantum signals. A receiver unit has a quantum receiver with at least one detector configured to detect quantum signals; a first classical communication device; and a passive optical splitter. The transmitter units are optically coupled to the receiver unit through the passive optical splitter. The passive optical splitter is optically coupled to the quantum receiver through a first spatial channel and optically coupled to the first classical communication device through a second spatial channel. The first spatial channel and second spatial channel are separate spatial channels. The passive optical splitter is configured to distribute an inputted optical signal irrespective of its wavelength.

Quantum communication system and a quantum communication method

A transmitter for a continuous variable quantum communication system, the transmitter including a coherent light source and a first controller to apply a first signal to the coherent light source such that the coherent light source generates coherent light. The transmitter also including a first optical component to produce optical intensity modulation. The transmitter including a second controller to apply a second signal to the optical component such that a light pulse is emitted during a period of time that a first part of the generated light is received, and a light pulse is emitted during a period of time that a second part of the generated light is received. A phase control element and an intensity control element encode information in a continuum of values of the phase and amplitude of an emitted light pulse.

Optical device, a transmitter for a quantum communication system and a quantum communication system

An optical device, comprising an optical component, configured to produce optical amplification; a component configured to intermittently supply coherent light to said optical component; and a controller, configured to apply a time varying signal to said optical component such that a plurality of light pulses are emitted during each period of time that said coherent light is received, wherein the plurality of light pulses emitted during each period have a fixed phase relation.

Optical device

A quantum communication system, comprising: a quantum transmitter optically coupled to a first waveguide; a first communication device optically coupled to a second waveguide; a multi-core optical fiber comprising a first core and a second core; a spatial multiplexing unit, configured to optically couple the first waveguide to the first core and the second waveguide to the second core.

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Cambridge, United Kingdom

Bernd Matthias Frohlich