Abstract: A quantum communications system includes a communications system that operates with a quantum key distribution (QKD) system, which includes a transmitter node, a receiver node, and a quantum communications channel coupling the transmitter node and receiver node. The transmitter node may be configured to transmit to the receiver node a bit stream of optical pulses, and switch between first and second QKD protocols based upon at least one channel condition.

Abstract: An optical system for use with a vacuum chamber may include a target to be positioned within the vacuum chamber, a laser source, and an optical assembly to be positioned within the vacuum chamber between the target and the laser source. The optical assembly may include a housing, a frame, a lens carried by the frame, and spiral flexures each having a respective proximal end coupled to the frame. In addition, the optical assembly may include a plurality of flexure actuators, where each flexure actuator is coupled between the housing and a distal end of a respective spiral flexure.

Abstract: A quantum communications system includes a communications system that operates with a quantum key distribution (QKD) system, which includes a transmitter node, a receiver node, and a quantum communications channel coupling the transmitter node and receiver node. The transmitter node may be configured to transmit to the receiver node a bit stream of optical pulses, and switch between first and second QKD protocols based upon at least one channel condition.

Abstract: An acousto-optic system may include a laser source, and an AOM coupled to the laser source and having an acousto-optic medium and transducer electrodes carried by the medium. The acousto-optic system may also include an interface board with a dielectric layer and signal contacts carried by the dielectric layer, and connections coupling respective signal contacts with respective transducer electrodes. Each connection may include a dielectric protrusion extending from the AOM, and an electrically conductive layer on the dielectric protrusion for coupling a respective transducer electrode to a respective signal contact.

Abstract: An automated building washing device generally includes a spray bar assembly coupled to a window washing swing stage. The spray bar assembly is horizontally movable from end-to-end along the longitudinal direction of a window washing swing stage while spray heads rotate so that a relatively large portion of building surface can be quickly cleaned. The spray bar assembly includes a hollow rotating bar and spray heads inside of a shroud so that the bar can rotate as water or cleaning solution is sprayed onto the building surface for cleaning.

Abstract: A quantum communications system may include transmitter node, a receiver node, and a quantum communications channel coupling the transmitter node and receiver node. The transmitter node may be configured to co-propagate a first pulse for a quantum state and a second pulse to stabilize the quantum state through the quantum communications channel.

Abstract: An automated building washing device generally includes one or more rotational brushes having a vertical rotational axis coupled to a window washing swing stage. The brushes are horizontally movable from end-to-end along the longitudinal direction of a window washing swing stage while rotating about their vertical axis so that a relatively large portion of building surface can be quickly cleaned.

Abstract: A system may include a laser source, and an AOM coupled to the laser source. The AOM may include an acousto-optic medium, and transducer electrodes carried by the acousto-optic medium. The system may also include an interface board having a dielectric layer, and vertically extending signal vias within the dielectric layer. Each vertically extending signal via may have a lower end in contact with a respective transducer electrode. The interface board may have laterally extending signal traces carried by the dielectric layer. Each laterally extending signal trace may be in contact with an upper end of a respective vertically extending signal via.

Abstract: A quantum communications system includes a communications system that operates with a quantum key distribution (QKD) system, which includes a transmitter node, a receiver node, and a quantum communications channel coupling the transmitter node and receiver node. The transmitter node may be configured to transmit to the receiver node a bit stream of optical pulses, and switch between first and second QKD protocols based upon at least one channel condition.

Abstract: An automated building washing device generally includes one or more rotational brushes having a vertical rotational axis coupled to a window washing swing stage. The brushes are horizontally movable from end-to-end along the longitudinal direction of a window washing swing stage while rotating about their vertical axis so that a relatively large portion of building surface can be quickly cleaned.

Abstract: A system may include a laser source, an acousto-optic modulator (AOM) coupled to the laser source, an atom trap, and an optical body coupled between the AOM and the atom trap and having a plurality of spaced apart optical signal channels etched therein. At least one piezoelectric transducer may be coupled to each of the optical signal channels, and a beam polarization controller may be coupled to the piezoelectric transducers.

Abstract: A quantum communications system may include a transmitter node, a receiver node, and a quantum communications channel coupling the transmitter node and receiver node. The receiver node may be configured to arrange a received bit stream of optical pulses from the transmitter node into time bins, convert the optical pulses in the time bins into corresponding optical pulses in frequency bins, and detect respective optical pulse values from each of the frequency bins.

Abstract: A quantum communications system may include communications system that operates with a quantum key distribution (QKD) system, which includes a transmitter node, a receiver node, and a quantum communications channel coupling the transmitter node and receiver node. The transmitter node may cooperate with the quantum communications channel defining at least one Talbot effect image position along the quantum communications channel. The receiver node may be located along the quantum communications channel at the at least one Talbot effect image position.

Abstract: A quantum communications system includes a communications system that operates with a quantum key distribution (QKD) system, which includes a transmitter node, a receiver node, and a quantum communications channel coupling the transmitter node and receiver node. The transmitter node may cooperate with the quantum communications channel defining a Talbot effect image position along the quantum communications channel. The receiver node is located along the quantum communications channel at a midpoint of the Talbot effect image position.

Abstract: An automated building washing device generally includes one or more rotational brushes having a vertical rotational axis coupled to a window washing swing stage. The brushes are horizontally movable from end-to-end along the longitudinal direction of a window washing swing stage while rotating about their vertical axis so that a relatively large portion of building surface can be quickly cleaned.

Abstract: A quantum communications system may include a transmitter node, a receiver node, and a quantum communications channel coupling the transmitter node and receiver node. The transmitter node may cooperate with the quantum communications channel defining at least one Talbot effect image position along the quantum communications channel. The receiver node may use located along the quantum communications channel at the at least one Talbot effect image position.

Abstract: A quantum communications system may include a transmitter node, a receiver node, and a quantum communications channel coupling the transmitter node and receiver node. The transmitter node may cooperate with the quantum communications channel defining at least one Talbot effect image position along the quantum communications channel. The receiver node may use located along the quantum communications channel at the at least one Talbot effect image position.

Abstract: A quantum communications system may include a transmitter node, a receiver node, and a quantum communications channel coupling the transmitter node and receiver node. The receiver node may be configured to arrange a received bit stream of optical pulses from the transmitter node into time bins, convert the optical pulses in the time bins into corresponding optical pulses in frequency bins, and detect respective optical pulse values from each of the frequency bins.

Abstract: An automated washing system for vertical surfaces of buildings can include a frame, a main brush rotatably disposed in the frame, at least two bumper wheels provided to opposing ends of the frame where the at least two bumper wheels can contact the vertical surfaces of building during a cleaning operation; and an electric drive motor disposed adjacent one of the opposing circular ends of the main brush.

Abstract: A system may include a laser source configured to generate a first laser light beam, an atom trap, and a multi-channel acousto-optic modulator (AOM). The multi-channel AOM may include a beamsplitter to split the first laser light beam into a plurality of second laser light beams for the atom trap, a common acousto-optic medium configured to receive the plurality of second laser light beams, and a respective plurality of electrodes coupled to the common acousto-optic medium for each of the second laser light beams. The system may also include a plurality of radio frequency (RF) drivers each configured to generate respective RF drive signals for each of the plurality of electrodes.