Abstract: Apparatuses and methods for producing and/or receiving an optical beam are disclosed, A phased array on a chip comprises phase shifters and off-chip couplers to provide phase controlled pixels. An optical system is arranged in front of the phased array. The optical system is configured to concentrate light from the phased array and/or expand a received beam of light for input into the phased array.

Abstract: Apparatuses and methods for producing and/or receiving an optical beam are disclosed, A phased array on a chip comprises phase shifters and off-chip couplers to provide phase controlled pixels. An optical system is arranged in front of the phased array. The optical system is configured to concentrate light from the phased array and/or expand a received beam of light for input into the phased array.

Abstract: Methods and apparatus for distribution of keys are disclosed. An optical signal for carrying encoded information in accordance with a quantum key distribution scheme is generated. The generated optical signal has a wavelength which is changed to another wavelength prior to transmission of the optical signal. The optical signal carrying the encoded information and having the changed wavelength is received, where after decoding of the information takes place by means of detector apparatus operating in the changed wavelength.

Abstract: According to an example aspect of the present invention, there is provided an apparatus (201) comprising adjustable optical equipment (290), a position sensitive photodetector (280), at least one light emitter (220), and control circuitry (104) configured to cause the light emitter (220) and the adjustable optical equipment (290) to output from the apparatus (201) a divergent beam of light, to determine a location of a light signal on the position sensitive photodetector (280) and to cause at least one of the at least one light emitter (220) and the adjustable optical equipment (290) to output from the apparatus (201) a collimated beam of light to a direction selected based at least in part on the location of the light signal on the position sensitive photodetector (280).

Abstract: Directional optical communications are provided between devices such as at least one pixel is selected from an array of pixels provided by an image projecting device for emitting light from an emitting device towards a target area of a receiving device. Light is then emitted by the selected at least one pixel towards the target area.

Abstract: The disclosure relates to secured wireless communications. A sender device emits randomly photons in a first polarization, a second polarization and a third polarization without aligning a polarization system in a plane perpendicular to the first and second polarizations with a recipient device. The recipient device is adapted for detection of events in association with six polarizations. The recipient device selects randomly polarization basis for measurement of the received photons. Information of detected events in association with three basis is communicated to the sender device. The information from the recipient device and information stored in the sender device is processed to determine events where same polarization basis was used by the sender device and the recipient device.

Abstract: In accordance with an example embodiment of the present invention, there is provided an apparatus comprising a dual-rail encoder (120) configured to receive light from a light source and to output dual-rail encoded light, a combiner (130) configured to convert the dual-rail encoded light into polarization encoded light, and at least one processing core configured to obtain compensation adjustment information concerning a fibre (145) and to control the dual-rail encoder (120) based at least in part on the compensation adjustment information.

Abstract: An apparatus may include an optical combiner configured to combine a first optical beam having an adjusted first polarization with a second optical beam having an adjusted second polarization into an output beam having a third polarization. The third polarization may be a linear combination of the adjusted first polarization and the adjusted second polarization. Information may be communicated by adjusting the polarization according to an information source.

Abstract: Methods and apparatus for use in quantum cryptographic applications are disclosed. An optical signal having a first wavelength is encoded for quantum cryptography at a stage where the optical signal is on at least two signal paths. The wavelength of the encoded optical signal on the at least two signal paths is converted to a second wavelength before the optical signal is encoded for transmission. Encoding for transmission is applied to the optical signal on the second wavelength.

Abstract: A light input is divided into a plurality of light outputs by a structure comprising a first beam splitter configured to divide the light Input into a first part and a second part, a first polarization beam splitter configured to provide from the first part a first polarized part and a second polarized part, wherein the first polarized part is for providing a first output and the second polarized part for providing a second output, at least one polarization altering device configured to alter the polarization of light in the second part, and at least one second polarization beam splitter configured to receive light altered by respective at least one polarization altering device and provide therefrom at least one third polarized part for providing at least one third output. A light output can be generated based on similar principles in reverse.

Abstract: Methods and apparatuses, including computer program code are disclosed. The apparatus may include at least one processor and at least one memory including computer program code. The at least one processor, the at least one memory, and the computer program code may be configured to cause the apparatus to generate a divergent beam for an optical source that is coincident with a divergent beam for an optical detector. The apparatus may determine an adjustment to a mirror to cause an optical alignment of an incoming beam with the optical detector based on at least an optical intensity across the optical detector, wherein the alignment is with respect to at least another apparatus. The apparatus may adjust a position of the mirror according to the determined adjustment, and change the divergent beam to a collimated beam to enable optical communications with the other apparatus via the collimated beam.

Abstract: For secure wireless communications the sender device uses a rail encoder that outputs dual rail-encoded states of light in a time slot. The states of light dual rail-encode information according to a phase and/or intensity difference between the dual rails, and the rail-encoded states of light may further be converted to a polarization-encoded state. This may be implemented using at least two polarizing beam-splitters with at least one quarter-wave plate disposed therebetween; and/or with integrated waveguides that convert three optical inputs to two optical outputs that are input to a polarization rotator-combiner. The encoder may randomly define the polarization-encoded state such as by randomly selecting from a finite number of at least N=3 possible polarization rotations. The recipient device may use 2N parallel, channels to decode the dual rail-encoded states of light, each channel comprising a detector configured to detect one of N possible polarization states.

Abstract: Apparatuses and methods for producing and/or receiving an optical beam are disclosed, A phased array on a chip comprises phase shifters and off-chip couplers to provide phase controlled pixels. An optical system is arranged in front of the phased array. The optical system is configured to concentrate light from the phased array and/or expand a received beam of light for input into the phased array.

Abstract: Directional optical communications are provided between devices such as at least one pixel is selected from an array of pixels provided by an image projecting device for emitting light from an emitting device towards a target area of a receiving device. Light is then emitted by the selected at least one pixel towards the target area.

Abstract: Adjustment of an optica! component of a device comprises determining of at least one derivative of coupling efficiency of the optical component as a function of parameters used for control of a steering function of the optica! component. At least one oscillating component is induced into the parameters for the determining. The adjustment of the optical component is based on the determined at least one derivative.

Abstract: Methods and apparatuses for communication between a mobile device and a target device are disclosed. Information of a target device is determined by means of at least one element of a mobile device for providing an optical link with the target device. An optical component of the mobile device is then aligned with an optical component of the target device based on said information determined by the mobile device. The target device can obtain information of relative positioning of the target device and the mobile device determined for the purposes of providing an optical link between the target device and the mobile device and the optical component thereof can be aligned with the optical component of the mobile device based on the information.

Abstract: Methods and apparatus for distribution of keys are disclosed. An optical signal for carrying encoded information in accordance with a quantum key distribution scheme is generated. The generated optical signal has a wavelength which is changed to another wavelength prior to transmission of the optical signal. The optical signal carrying the encoded information and having the changed wavelength is received, where after decoding of the information takes place by means of detector apparatus operating in the changed wavelength.

Abstract: An apparatus including: addition circuitry configured to receive simultaneously a probe signal that has passed through a channel having a complex transmission and a reference signal and configured to produce at least: a plurality of weighted additions including an addition of the probe signal and the reference signal with different relative phase rotations between the probe signal and the reference signal for each weighted addition; and processing circuitry configured to use at least two of the plurality of weighted additions to determine a first quantitative parameter for the channel dependent upon the complex transmission for the channel.

Abstract: The disclosure relates to secured wireless communications. A sender device emits randomly photons in a first polarisation, a second polarisation and a third polarisation without aligning a polarisation system in a plane perpendicular to the first and second polarisations with a recipient device. The recipient device is adapted for detection of events in association with six polarisations. The recipient device selects randomly polarisation basis for measurement of the received photons. Information of detected events in association with three basis is communicated to the sender device. The information from the recipient device and information stored in the sender device is processed to determine events where same polarisation basis was used by the sender device and the recipient device.

Abstract: An apparatus including: addition circuitry configured to receive simultaneously a probe signal that has passed through a channel having a complex transmission and a reference signal and configured to produce at least: a plurality of weighted additions including an addition of the probe signal and the reference signal with different relative phase rotations between the probe signal and the reference signal for each weighted addition; and processing circuitry configured to use at least two of the plurality of weighted additions to determine a first quantitative parameter for the channel dependent upon the complex transmission for the channel.