Abstract: An electronic package comprising: an active element; a first substrate; and a second substrate, the first substrate comprising a plurality of conductive tracks on a first surface, the second substrate comprising a plurality of conductive tracks on a second surface, the active element being provided on the first surface of the first substrate, the second substrate being provided overlying the first surface of the first substrate such that a face of the second substrate which is opposite to the second surface is in contact with the first surface, the second substrate having an opening to allow access to the active element and being positioned on the first substrate such that at least some of the plurality of conductive tracks on the first surface are exposed, the active element being electrically connected to at least some of the plurality of tracks on the first substrate and the plurality of tracks on the second substrate.

Abstract: A photon source comprising: a quantum dot; and an optical cavity, the optical cavity comprising: a diffractive Bragg grating “DBG”; and a planar reflection layer, the DBG comprising a plurality of concentric reflective rings surrounding a central disk and at least one conductive track extending from the central disk across the plurality of concentric rings, the quantum dot being provided within the central disk and the planar reflection layer being provided on one side of the DBG to cause light to be preferentially emitted from the opposing side of the DBG.

Abstract: An optical device includes a first semiconductor substrate, a reference laser configured to generate coherent light, a plurality of first optical components, a plurality of second optical components, one or more first controllers configured to apply phase control signals to said plurality of first optical components to apply a phase shift, and one or more second controllers configured to apply pulse control signals to said plurality of second optical components such that a light pulse is outputted during a period of time that coherent light is received. The relative phase between emitted light pulses from the plurality of second optical components is controlled by the relative phase shifts applied by the one or more first controllers.

Abstract: An investigative system, comprising: an emitter, said emitter being adapted to output a plurality of pulses, said plurality of pulses being arranged in a first temporal pattern; a receiver adapted to receive said plurality of pulses; and a correlator adapted to correlate the first pattern with the received plurality of pulses to output a correlated pattern.

Abstract: An investigative system, comprising: an emitter, said emitter being adapted to output a plurality of pulses, said plurality of pulses being arranged in a first temporal pattern; a receiver adapted to receive said plurality of pulses; and a correlator adapted to correlate the first pattern with the received plurality of pulses to output a correlated pattern.

Abstract: An optical device, comprising: a first semiconductor substrate; a reference laser, configured to generate coherent light; a plurality of first optical components, wherein the reference laser is optically coupled to the plurality of first optical components, wherein each of the plurality of first optical components is configured to output coherent light during a period of time that coherent light from the reference laser is received; a plurality of second optical components, the second optical components configured to produce optical intensity modulation, wherein each of the plurality of first optical components is optically coupled to at least one corresponding second optical component; wherein the plurality of first optical components each comprises a laser, an optical amplifier or a phase modulator, and the plurality of second optical components each comprises a laser, an optical amplifier or an intensity modulator, and wherein when a first optical component comprises a laser or an optical amplifier the

Abstract: An optical device comprising: a quantum dot, said quantum dot comprising InAs and adapted to emit radiation in the wavelength range from 1200 nm to 2000 nm; a supporting layer supporting said quantum dot, said supporting layer being lattice matched to InP; and wherein the longest dimension of the base of the quantum dot provided parallel to the supporting layer is within 20% of the shortest dimension of the base provided parallel to the supporting layer.

Abstract: An optical device comprising: a substrate; a cavity structure on the substrate, comprising a quantum emitter in contact with one or more semiconductor layers; wherein the or all of the semiconductor layers in contact with the quantum emitter have a thickness larger than the height of the quantum emitter.

Abstract: An optical device comprising: a substrate; a cavity structure on the substrate, comprising a quantum emitter in contact with one or more semiconductor layers; wherein the or all of the semiconductor layers in contact with the quantum emitter have a thickness larger than the height of the quantum emitter.

Abstract: An optical device comprising a quantum dot provided in a resonant confinement structure, an output from said confinement structure and a pulsed excitation source for said quantum dot, wherein the quantum dot is configured to allow the emission of photons having a first energy in response to a pulse from said excitation source, said resonant confinement structure providing optical confinement, the first energy being different to the resonant energy of the resonant confinement structure, the optical device further comprising a timing unit, said timing unit being configured to select photons which have been emitted from the quantum dot due to excitation by a pulse, the timing unit selecting photons emitted after the duration of the pulse which caused the emission of the photons.

Abstract: According to one embodiment, a quantum information system includes a source of time dependent entangled photons and an indicating unit. The indicating unit indicates the entangled state of the entangled photons based on the emission time of one or more of the entangled photons.

Abstract: An optical system including: a photon source; first directing elements configured to direct photons to follow a first path through the optical system; second directing elements configured to direct photons to follow a second path through the optical system, wherein the second path is the reverse of the first path, photons travelling through the first path having a different polarization to those travelling through the second path; and a mechanism varying the relative phase shift between photons following the first path and photons following the second path.

Abstract: A system for quantum teleportation of a quantum state of an input photon, including: a light emitting diode configured to produce a polarization entangled photon pair; a beam splitter configured to direct photons of the entangled photon pair along respective first and second paths; a measurement unit performing a joint measurement on the input photon; a timing unit configured to measure a first delay between the input photon and the photon of the entangled photon pair at a point of maximum indistinguishability of the photons as they pass through the joint measurement unit, and to measure a second delay between the two photons of the entangled photon pair as they exit the light emitting diode; a controller configured to determine a teleportation measurement is valid if the first delay is within a first predetermined timing window and the second delay is within a second predetermined timing window.

Abstract: An optical device comprising a quantum dot provided in a resonant confinement structure, an output from said confinement structure and a pulsed excitation source for said quantum dot, wherein the quantum dot is configured to allow the emission of photons having a first energy in response to a pulse from said excitation source, said resonant confinement structure providing optical confinement, the first energy being different to the resonant energy of the resonant confinement structure, the optical device further comprising a timing unit, said timing unit being configured to select photons which have been emitted from the quantum dot due to excitation by a pulse, the timing unit selecting photons emitted after the duration of the pulse which caused the emission of the photons.

Abstract: A component comprising a qubit and a controller for said qubit, said component comprising a quantum dot and an excitation portion configured to produce a neutral exciton state in said quantum dot to form said qubit, the component further comprising a measuring unit to make an optical measurement relating to the orientation of said state, wherein said controller comprises voltage source coupled to electrical contacts configured to apply a modulated electric field across said quantum dot, wherein the modulation is faster than the decay time of said neutral exciton state.

Abstract: An optical data retrieval system configured to retrieve data from a data storage medium, including: a source of n path-entangled photons, where n is an integer of at least 2; a detector system configured to determine if n photons have been received; and a mechanism to direct photons from the source to the data storage medium and to the detector system.

Abstract: A photon source comprising: a quantum dot; electrical contacts configured to apply an electric field across said quantum dot: and an electrical source coupled to said contacts, said electrical source being configured to apply a potential such that carriers are supplied to said quantum dot to form a bi-exciton or higher order exciton, wherein said photon source further comprises a barrier configured to increase the time which a carrier takes to tunnel to and from said quantum dot to be greater than the radiative lifetime of an exciton in the quantum dot, the quantum dot being suitable for emission of entangled photons during decay of a bi-exciton or higher order exciton.

Abstract: A component comprising a qubit and a controller for said qubit, said component comprising a quantum dot and an excitation portion configured to produce a neutral exciton state in said quantum dot to form said qubit, the component further comprising a measuring unit to make an optical measurement relating to the orientation of said state, wherein said controller comprises voltage source coupled to electrical contacts configured to apply a modulated electric field across said quantum dot, wherein the modulation is faster than the decay time of said neutral exciton state.

Abstract: A photon source comprising: a quantum dot; electrical contacts configured to apply an electric field across said quantum dot: and an electrical source coupled to said contacts, said electrical source being configured to apply a potential such that carriers are supplied to said quantum dot to form a bi-exciton or higher order exciton, wherein said photon source further comprises a barrier configured to increase the time which a carrier takes to tunnel to and from said quantum dot to be greater than the radiative lifetime of an exciton in the quantum dot, the quantum dot being suitable for emission of entangled photons during decay of a bi-exciton or higher order exciton.

Abstract: According to one embodiment, a quantum information system includes a source of time dependent entangled photons and an indicating unit. The indicating unit indicates the entangled state of the entangled photons based on the emission time of one or more of the entangled photons.