Kabushiki Kaisha Toshiba

James Dynes

Andrew James Shields

Zhiliang Yuan

Marco Lucamarini

Robert Ian Woodward

Bernd Matthias Frohlich

Andrew Sharpe

Benjamin Marsh

Joanna Krystyna Skiba-Szymanska

Taofiq Paraiso

Mirko Sanzaro

Joseph Dolphin

Benjamin Griffiths

Christopher Meayers

Andrew Simpkins

An optical transmitter for a Quantum Key Distribution (QKD) system, the transmitter comprising: a multi-modal laser; a wavelength tuneable laser arranged to inject light into a cavity of the multi-modal laser, so as to cause the multi-modal laser to output light at a selected wavelength for use in generating pulses to be output by the transmitter; and a modulator for controlling a phase shift between successive pulses output from the transmitter.

Optical transmitter for a quantum key distribution system

A method for use in a quantum communication network comprising a first node, a second node and a third node, the method performed by the third node, the method comprising:

Quantum network and authentication method

An authentication method for quantum communication between two nodes, the method comprising:

Authentication method and system, a quantum communication network, and a node for quantum communication

A photon detection system comprising an avalanche photodiode configured to generate a photodiode signal in response to an incident photon. The photon detection system also comprises a biasing circuit configured to supply a gating signal to the avalanche photodiode. The gating signal is a periodic signal configured to reverse bias the avalanche photodiode above and below its breakdown voltage for photon detection during each period. The photon detection system further comprises a non-reflective filter circuit configured to receive, at an input port, the photodiode signal, and provide, at a first output port, a first filtered output signal by applying a low-pass filter with a first cut-off frequency to the received photodiode signal.

Photon detection system including an avalanche photodiode and a biasing circuit to supply a gating signal

A transmitter for a quantum communication system, comprising:

Transmitter for a quantum communication system, a quantum communication system and a method of generating intensity modulated photon pulses

A quantum communication system for distributing a key between first and second units, the system being configured to implement phase-based measurement device independent quantum cryptography, the system comprising first and second units adapted to apply phase shifts to light pulses and a detection unit adapted to cause interference between light pulses received from the first and second units and measure said interference, wherein the first and second units each comprise at least one phase modulator adapted to apply a phase shift, said phase shift comprising a global phase component and a relative phase component, wherein said global phase component represents a phase shift selected randomly in the range from 0&#xb0; to 360&#xb0; from a fixed phase reference and said relative phase component is a phase shift selected randomly from 0&#xb0;, 90&#xb0;, 180&#xb0; and 270&#xb0; from the phase shift introduced by the global phase component.

Optical quantum communication system

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

A detection system for monitoring the intensity of a stream of modulated pulses, the system comprising a controller configured to provide a control signal to a component outputting modulated pulses the control signal controlling the level of modulation for each pulse exiting the component and a detector configured to measure the intensity of the pulses in the stream of pulses exiting the component outputting modulated pulses, wherein the detector comprises a gated detector, the controller being configured to send a gating signal to said detector, wherein said gating signal varies the gain of the detector with the control signal, such that pulses with a selected modulation level can be detected.

System and method for intensity monitoring

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.

Quantum communication system and a quantum communication method

Interference system and an interference method

A transmitter for a quantum communication system, the transmitter comprising an interferometer, the interferometer having a first path with a phase modulator and a second path configured such that light pulses entering the interferometer follow either the first path or the second path, the output of the first and second paths being combined, the transmitter further comprising an optical filter positioned such that photons exiting the interferometer pass through the optical filter, the optical filter being configured to restrict the frequency range of pulses passing through the optical filter and temporally broaden the pulses.

Quantum communication system

A quantum communication system comprising a receiver and a plurality of transmitters, said receiver comprising a detector sub-system, each of said transmitters being configured to emit pulses of radiation, said detector subsystem comprising at least one detector, said detector being configured to detect said light pulses, the system comprising a timing control module, said timing control module being configured to control the number of light pulses received by the detector sub-system, such that just one light pulse from one transmitter reaches the detector sub-system at any one time, the timing control module also allowing the transmitter which sent said pulse to be identified.

Quantum communication network

A communication system comprising an emitter of weak light pulses, a detector which is capable of detecting single photons, and a source of a clock signal, wherein said emitter and detector are synchronized using said clock signal, the system further comprising a frequency divider for said clock signal to produce a reduced frequency clock signal and a clock regenerator for regenerating the original clock signal from the reduced frequency clock signal, the system further comprising a communication channel configured to communicate the clock signal between the emitter and detector, the clock signal being reduced before sending through said channel and reconstructed after it has exited said channel.

Communication system and method

A quantum communication system, said system comprising:

Growing community of inventors

Cambridge, United Kingdom

James Dynes