Abstract: A multi-aperture free-space optical communications receiver comprises a plurality of telescopes each having a clear objective aperture with a diameter between 50 mm and 250 mm and arranged for receiving light collectively from an optical communications light source. A coherent combiner unit is configured for coherently combining the collectively received light to produce a combined optical signal therewith. Each telescope is arranged in association with, respectively, a wavefront detector to determine a wavefront of said received light directed to it by the respective telescope, a steerable reflector unit including a deformable mirror controllable to deform according to said determined wavefront such that said received light is reflected by the deformable mirror with a modified wavefront, and an optical signal receiver comprising a single-mode optical fibre.

Abstract: The invention relates to the field of Free Space Optics (FSO), more specifically it is directed to: a method of obtaining a connection between at least two optical signal nodes, of a FSO, communication system each node comprising a transmitting device and receiving device; and transmitting via the transmitting device of a first node, a first diverged optical signal into an optical medium; receiving at the receiving device of the second node the first diverged optical signal and transmitting via the transmitting device of the second node a second diverged signal to the receiving device of the first node to establish a location of said first node establishing a connection, after which; the first node switches from the diverged optical signal to a narrower optical signal for the transmission of data via the connection.

Abstract: An optical system (100) comprising: a transmitter module (102) configured to transmit a sequence of optical pulses (300), each optical pulse in the sequence (300) having a different magnitude to each other optical pulse in the sequence (300); a receiver module (104) comprising one or more optical signal detectors, the receiver module (104) configured to receive the sequence of optical pulses (300) transmitted by the transmitter module (102); and one or more processors (110) configured to process the sequence of optical pulses received by the receiver module (104) to select an optical pulse from the received sequence of optical pulses (400) based on one or more predetermined criteria. The one or more predetermined criteria include a criterion that the selected optical pulse does not saturate the one or more optical signal detectors.

Abstract: A multi-aperture free-space optical communications receiver comprises a plurality of telescopes each having a clear objective aperture with a diameter between 50 mm and 250 mm and arranged for receiving light collectively from an optical communications light source. A coherent combiner unit is configured for coherently combining the collectively received light to produce a combined optical signal therewith. Each telescope is arranged in association with, respectively, a wavefront detector to determine a wavefront of said received light directed to it by the respective telescope, a steerable reflector unit including a deformable mirror controllable to deform according to said determined wavefront such that said received light is reflected by the deformable mirror with a modified wavefront, and an optical signal receiver comprising a single-mode optical fibre.

Abstract: The invention relates to the field of Free Space Optics (FSO), more specifically it is directed to: a method of obtaining a connection between at least two optical signal nodes, of a FSO, communication system each node comprising a transmitting device and receiving device; and transmitting via the transmitting device of a first node, a first diverged optical signal into an optical medium; receiving at the receiving device of the second node the first diverged optical signal and transmitting via the transmitting device of the second node a second diverged signal to the receiving device of the first node to establish a location of said first node establishing a connection, after which; the first node switches from the diverged optical signal to a narrower optical signal for the transmission of data via the connection.

Abstract: Apparatus for and method of transmitting an optical signal by a Free Space Optical, FSO, communication system, the method comprising: transmitting, by an optical signal transmitter (104), an optical signal (700) into at least part of a volume of an optical medium (302); and controlling, by a controller, the optical signal transmitter (104), to scan the at least part of the volume (302) using the optical signal (700) in a sequence of non-overlapping loops (704, 708). The sequence of non-overlapping loops (704, 708) may be a sequence of non-overlapping, concentric circular loops.

Abstract: A free space optical communication system receiver (500) comprising: a central optical sensor (600); and a plurality of further optical sensors (601-604) disposed around a peripheral edge of the central optical sensor (600). The free space optical communication system receiver (500) may be coupled to means for moving the free space optical communication system receiver (500) relative to an incoming optical signal (510). A controller (508) may be configured to, using measurements of the incident optical signal (510) by the plurality of further optical sensors (601-604), control the means so as to move the free space optical communication system receiver (500) relative to the incident optical signal (510).

Abstract: Imaging apparatus on a host platform having an external surface, the external surface comprising a first surface facing a first direction and a second surface facing a second direction, the second direction being different to the first, the apparatus comprising a first and second plurality of single pixel detectors (10) distributed about said external surface such that the first plurality of single pixel detectors are distributed over the first surface and the second plurality of single pixel detectors are distributed over the second surface, each single pixel detector being configured to receive radiation reflected by an object or region of interest (18) and generate two-dimensional image data representative thereof, the apparatus further comprising an image processing module (16) for receiving said two-dimensional image data from each of a plurality of single pixel detectors (10) and reconstructing a three-dimensional image of said object or region of interest (18) using a ghost imaging algorithm.

Abstract: A free space optical communication system receiver (500) comprising: a central optical sensor (600); and a plurality of further optical sensors (601-604) disposed around a peripheral edge of the central optical sensor (600). The free space optical communication system receiver (500) may be coupled to means for moving the free space optical communication system receiver (500) relative to an incoming optical signal (510). A controller (508) may be configured to, using measurements of the incident optical signal (510) by the plurality of further optical sensors (601-604), control the means so as to move the free space optical communication system receiver (500) relative to the incident optical signal (510).

Abstract: Apparatus for and method of transmitting an optical signal by a Free Space Optical, FSO, communication system, the method comprising: transmitting, by an optical signal transmitter (104), an optical signal (700) into at least part of a volume of an optical medium (302); and controlling, by a controller, the optical signal transmitter (104), to scan the at least part of the volume (302) using the optical signal (700) in a sequence of non-overlapping loops (704, 708). The sequence of non-overlapping loops (704, 708) may be a sequence of non-overlapping, concentric circular loops.

Abstract: An optical system (100) comprising: a transmitter module (102) configured to transmit a sequence of optical pulses (300), each optical pulse in the sequence (300) having a different magnitude to each other optical pulse in the sequence (300); a receiver module (104) comprising one or more optical signal detectors, the receiver module (104) configured to receive the sequence of optical pulses (300) transmitted by the transmitter module (102); and one or more processors (110) configured to process the sequence of optical pulses received by the receiver module (104) to select an optical pulse from the received sequence of optical pulses (400) based on one or more predetermined criteria. The one or more predetermined criteria include a criterion that the selected optical pulse does not saturate the one or more optical signal detectors.

Abstract: The following invention relates to an optical device for use in a system that requires optical zoom or focus abilities, particularly for providing pre-set zoom parameters with a very low energy requirement. There is provided an optical magnification device comprising at least one pair of optically aligned deformable reflectors, wherein each reflector pair has at least two configurations, wherein selection of a first and a second configuration of said deformable reflector pairs provides pre-defined magnification states, such that in any configuration one reflector is substantially concave and the other is substantially convex; at least one controller may cause both the reflectors to move between said at least two configurations.

Abstract: Imaging apparatus on a host platform having an external surface, the external surface comprising a first surface facing a first direction and a second surface facing a second direction, the second direction being different to the first, the apparatus comprising a first and second plurality of single pixel detectors (10) distributed about said external surface such that the first plurality of single pixel detectors are distributed over the first surface and the second plurality of single pixel detectors are distributed over the second surface, each single pixel detector being configured to receive radiation reflected by an object or region of interest (18) and generate two-dimensional image data representative thereof, the apparatus further comprising an image processing module (16) for receiving said two-dimensional image data from each of a plurality of single pixel detectors (10) and reconstructing a three-dimensional image of said object or region of interest (18) using a ghost imaging algorithm.

Abstract: There is disclosed a directional multi-band antenna comprising: a primary reflector, at least one secondary reflector, a multi-layer dielectric layer selectively reflective or transmissive of incident radiation according to wavelength, the layer being provided at the surface of either the primary or the secondary reflector, an RF unit comprising a collocated sensor and transmitter, an Optical unit comprising a collocated sensor and transmitter, arranged such that the primary reflector is for passing signals between the secondary reflector and the environment, the secondary reflector is firstly for passing signals between the primary reflector and the RF unit, and secondly for passing signals between the primary reflector and the Optical unit and arranged such that the antenna is operable to transmit or receive, RF or Optical signals, along a common beam axis.

Abstract: There is disclosed A directional multi-band antenna, the antenna comprising: —an optical unit comprising an optical sensor; —an RF unit comprising an RF sensor; —a substantially planar optical lens, the optical lens comprising surface relief elements for beam forming, the lens being arranged to focus optical signal beams, incident along a first optical axis, onto the optical sensor, the optical lens being substantially transparent to RF signals, —an RF beam forming device arranged to receive RF signals incident along the first optical axis and focus such RF signals onto the RF sensor.

Abstract: There is disclosed a directional multi-band antenna comprising a substrate structure, a plurality of RF units arranged at the substrate structure to provide an RF phased array, the RF phased array having an angular scan range, an array of optical units arranged at the substrate structure and interspersed amongst the RF units, an array of optical lensing devices supported over the substrate structure, the array of optical lensing devices being substantially RF transmissive and being arranged to correspond with the arrangement of the optical units, such that each optical unit may communicate light signals with an associated optical lensing device so as to communicate light signals along an optical axis within the angular scan range of the RF phased array.

Abstract: The following invention relates to an optical device for use in a system that requires optical zoom or focus abilities, particularly for providing pre-set zoom parameters with a very low energy requirement. There is provided an optical magnification device comprising at least one pair of optically aligned deformable reflectors, wherein each reflector pair has at least two configurations, wherein selection of a first and a second configuration of said deformable reflector pairs provides pre-defined magnification states, such that in any configuration one reflector is substantially concave and the other is substantially convex; at least one controller may cause both the reflectors to move between said at least two configurations.

Abstract: There is disclosed a spectral imaging apparatus for processing electromagnetic (EM) radiation, the EM radiation originating from a target scene and comprising a wide range of frequencies, the system comprising: A dispersive element for receiving EM radiation from the target scene and promoting differing amounts of dispersion depending on the frequency of the EM radiation, A deformable lens arranged to receive EM radiation from the dispersive element, An imaging sensor for detecting EM radiation across the wide range of frequencies, and arranged to receive EM radiation from the deformable lens, Wherein the deformable lens is operable to adopt any one of a plurality of focal conditions, each focal condition tending to focus a different range of the EM radiation at the imaging sensor, each focal condition thereby defining a component band for the EM radiation.

Abstract: A method and apparatus for compensating for hysteresis in a system, the method comprising: determining a required input to the system from an output of the system using the Preisach model with the input of the Preisach model corresponding to the output of the system, and with the output of the Preisach model corresponding to the input of the system. The system may be an adaptive optics system. The input x may be an input voltage of an actuator that deforms a mirror, and the output y may be a value of a displacement of a mirror.

Abstract: A display assembly, comprising: a display device (30); a microlens array (34); and an eye tracker (8), for example a pupil tracker (8), and/or a head tracker; wherein plural pixels (150) or sub-pixels of the display device (30) are provided for each microlens (160) of the microlens array (34). The display may be adapted such that only certain pixels/sub-pixels (150) are activated/selected for any particular determined pupil/eye/head position, for example such that for each microlens (160), only one respective pixel/sub-pixel (150) is activated/selected for any particular determined pupil/eye/head position. The display device (30) may be a transparent display device (30), the microlens array (34) may be a switchable microlens array (34), and the display assembly may further comprise a light blocking device (32) that is switchable between a substantially light blocking state and a substantially light passing state.