A quantum key distribution device is provided with an encoding unit which encodes an optical pulse train; an intensity modulating unit which subjects the encoded optical pulse train to N (where N is an integer at least equal to 3) types of intensity modulation having mutually different intensities, with different timings; and a first key distillation processing unit which generates an encryption key on the basis of a data sequence obtained by removing data obtained from an optical pulse having a specific modulation pattern from a data sequence used by the encoding unit and the intensity modulating unit.

A switching network for effecting point-to-point communication between nodes has a time-varying switching configuration, which causes successive activation and deactivation of multiple channels of the switching network, a first of the channels connecting, when activated, a transmitter node and a first receiver node, and a second of the channels connecting, when activated, the transmitter node and a second receiver node. In a training phase, a method comprises: transmitting from the transmitter node via each channel a known training signal, to cause each receiver node to receive a distorted training signal, using the first distorted training signal and knowledge of the first known training signal to determine respective one or more transmit-side equalizer (EQ) coefficients for each channel, and storing, in memory accessible to the transmitter node, the first transmit-side EQ coefficients, in association with each channel, for use in conducting scheduled communications over the switching network in a communications phase.

A switching network for effecting point-to-point communication between nodes has a time-varying switching configuration, which causes successive activation and deactivation of multiple channels of the switching network, a first of the channels connecting, when activated, a transmitter node and a first receiver node, and a second of the channels connecting, when activated, the transmitter node and a second receiver node. In a training phase, a method comprises: transmitting from the transmitter node via each channel a known training signal, to cause each receiver node to receive a distorted training signal, using the first distorted training signal and knowledge of the first known training signal to determine respective one or more transmit-side equalizer (EQ) coefficients for each channel, and storing, in memory accessible to the transmitter node, the first transmit-side EQ coefficients, in association with each channel, for use in conducting scheduled communications over the switching network in a communications phase.

Optical communication modules and associated methods and computer program products for performing network communication security are provided. An example optical module includes a substrate, a first optoelectronic component supported by the substrate configured for operation with optical signals having a first wavelength, and a second optoelectronic component supported by the substrate configured for operation with optical signals having a second wavelength. The module further includes an optical communication medium defining a first end in optical communication with the first optoelectronic component and the second optoelectronic component and a second end. The module also includes security circuitry operably connected with the first optoelectronic component and the second optoelectronic component. The security circuitry determines the presence of a noncompliant component coupled with the optical communication medium at the second end based upon operation of the second optoelectronic component.

An optical wireless communication device comprises: at least one of a transmitter and a receiver configured to transmit and/or receive light comprising an optical wireless communication signal representing data; at least one adjustable shutter element associated with the at least one of a transmitter and a receiver, wherein the at least one adjustable shutter element and the associated at least one of the transmitter and the receiver are adjustable between a first configuration and a second configuration such that in the first configuration the at least one adjustable shutter element is configured to at least partially block or partially redirect light having a first selected property and at least partially allow light having a second selected property to pass through unaffected such that transmission and/or reception of the optical wireless communication signal by the at least one of the transmitter and the receiver is substantially altered.

An optical wireless communication device comprises: at least one of a transmitter and a receiver configured to transmit and/or receive light comprising an optical wireless communication signal representing data; at least one adjustable shutter element associated with the at least one of a transmitter and a receiver, wherein the at least one adjustable shutter element and the associated at least one of the transmitter and the receiver are adjustable between a first configuration and a second configuration such that in the first configuration the at least one adjustable shutter element is configured to at least partially block or partially redirect light having a first selected property and at least partially allow light having a second selected property to pass through unaffected such that transmission and/or reception of the optical wireless communication signal by the at least one of the transmitter and the receiver is substantially altered.

A signal generator includes a photonic circuit configured to output a sequence of solitons at a known rate. The solitons illuminate a high-speed photodiode that, in response, generates an electrical signal, such as a sinusoidal signal, which can be provided as input to a direct digital synthesizer configured to output successive phases of a selected waveform in response to electrical stimulus.

A signal generator includes a photonic circuit configured to output a sequence of solitons at a known rate. The solitons illuminate a high-speed photodiode that, in response, generates an electrical signal, such as a sinusoidal signal, which can be provided as input to a direct digital synthesizer configured to output successive phases of a selected waveform in response to electrical stimulus.

Devices, methods and systems for generating wideband, high-fidelity arbitrary radio frequency (RF) passband signals are described. A voltage tunable optical filter for arbitrary RF passband signal generation includes a first input configured to receive a broadband optical pulse train, a second input configured to receive a first control voltage representative of an amplitude signal, an electrooptic modulator to receive the broadband optical pulse train and the first control voltage, to modulate the broadband optical pulse train in accordance with the amplitude signal, and to produce two complementary optical outputs that form two arms of an interferometer, an optical delay component to impart an optical path difference into one of the complementary outputs of the electrooptic modulator, and a combiner or a splitter to receive two complementary optical outputs of the electrooptic modulator after impartation of the optical path difference and to produce an output interference pattern of fringes.

A system and method generates confined electromagnetic radiation emanating from a remote position along a line of sight. The system includes a laser arrangement and a wavefront modifier. The laser arrangement generates at least one laser beam. The wavefront modifier produces a spatial arrangement of foci of the laser beam directed along the line of sight. The foci of the laser beam induce plasma filaments within an atmosphere at the remote position along the line of sight. The plasma filaments emit the electromagnetic radiation emanating from the remote position along the line of sight.