Monostatic optical transceivers, systems, and methods of operating the same include a single aperture, a transmitter that provides a modulated and polarized optical transmit beam, a receiver that receives a modulated and polarized optical receive beam at an optical resonator included therein and processes the received optical receive beam to determine information from the received optical receive beam, a polarizing beam splitter that reflects the optical transmit beam, a polarization rotator that rotates the polarization of the reflected optical transmit beam by a fixed number of degrees in a transmit direction in a coordinate system of the monostatic transceiver, and a waveplate that modifies the polarization of the rotated optical transmit beam.

A system and method for high speed communication are provided. The system comprises a laser-based system for communication, the system comprising: an acquisition module configured to acquire and characterize a plurality of laser beams; a tracking module configured to track the acquired laser beams, the tracking module comprising: a beaconing feedback and beam divergence mechanism configured to control a beam and detect a beam; an adaptive learning unit configured to implement an adaptive learning detection algorithm to identify and track a unique optical signature from at least one of the acquired laser beams; and a pointing module configured to point at least one laser beam towards a target based on the acquired laser beams.

A communication unit (20) configured for wireless optical communication underwater, and including a communication transceiver (24), a housing (22), an adjustment mechanism (28), and a processor (40). The transceiver is accommodated in the housing, and includes a signal detector configured to receive an optical communication signal (50) approaching the unit within a main detection lobe centred on a receiver directivity axis (Ar), and/or includes a signal generator configured to emit an optical communication signal (52) via a main emission lobe centred on a transmitter directivity axis (At). The adjustment mechanism is configured to adjust orientation(s) of the receiver and/or transmitter directivity axes relative to the housing. The processor is configured to determine a directional coordinate (Φi, Θi) for an approaching light signal (50, 54), and to control the adjustment mechanism to automatically adjust and align the orientation of the directivity axes with the determined directional coordinate.

The disclosure provides for a method for reacquiring a communication link between a first communication device and a second communication device. The method includes using one or more processors of the first communication device to receive historical data related to the first communication device and an environment surrounding the first communication device. The one or more processors are then used to determine one or more trends in the historical data related to fading of the communication link. Based on the one or more trends, the one or more processors are used to determine a starting time and an initial search direction for a search for the communication link. The one or more processors then execute the search at the starting time from the initial search direction.

A switching instructor outputs a beacon light selection notification signal when a optical transceiver transmits a optical wireless signal of a beacon light and outputs a signal light selection notification signal when the optical transceiver transmits the optical wireless signal of the signal light. A spatial light modulator controller performs switching of a control signal given to each of the plurality of pixels of a spatial light modulator to: cause a phase delay in light received by each of the plurality of pixels of the spatial light modulator when the switching instructor outputs the beacon light selection notification signal and cause a phase delay in light received by each of the plurality of pixels of the spatial light modulator when the switching instructor outputs the signal light selection notification signal.

The technology employs a state-based power control loop (PCL) architecture to maintain tracking and communication signal-to-noise ratios at suitable levels for optimal tracking performance and data throughput in a free-space optical communication system. Power for a link is adjustable to stay within a functional range of receiving sensors in order to provide continuous service to users. This avoids oversaturation and possible damage to the equipment. The approach can include decreasing or increasing the power to counteract a surge or drop while maintaining a near constant received power at a remote communication device. The system may receive power adjustment feedback from another communication terminal and perform state-based power control according to the received feedback. This can include re-initializing and reacquiring a link with the other communication terminal automatically after loss of power, without human intervention. There may be a default state and discrete states including rain, fade, surge and unstable states.

An optronic system (100) for a countermeasure unit (10) to optically communicate with another communication terminal is disclosed. The countermeasure unit (10) comprises a laser beam source (12) and a directing device (14) for a laser beam (15) of the laser beam source (12) and is configured to dazzle or to jam an object of threat (50). The optronic system (100) comprising: a detector (110), a modulation unit (120), and a control unit (130). The detector (110) is configured to detect an incoming communication in an incoming signal (25). The modulation unit (120) is configured to demodulate the incoming signal (25) or cause a modulation of an outgoing laser beam (15). The control unit (130) is configured, in response to the detected incoming communication, to control the modulation unit (120) to demodulate the incoming signal (25) or to modulate the outgoing laser beam (15) to enable an optical communication via the laser beam source (12) of the countermeasure unit (10).

A system and method for high speed communication are provided. The system comprises a laser-based system for communication, the system comprising: an acquisition module configured to acquire and characterize a plurality of laser beams; a tracking module configured to track the acquired laser beams, the tracking module comprising: a beaconing feedback and beam divergence mechanism configured to control a beam and detect a beam; an adaptive learning unit configured to implement an adaptive learning detection algorithm to identify and track a unique optical signature from at least one of the acquired laser beams; and a pointing module configured to point at least one laser beam towards a target based on the acquired laser beams.

A free-space optical (FSO) transceiver having an optimum number of transmitters and receivers positioned in optimum locations on the transceiver plane to ensure maximum signal-to-interference and noise ratio (SINR) and to minimize the effects of vibration of the mobile platform and atmospheric turbulence. A defocal lens assembly having an adjustable distance between the transmitters and the lens assembly is further provided to maximize the optical coupling efficiency and the vibration tolerance by adjusting the defocusing length.

A laser communication system for an aircraft has optical head units, separate laser transmitting unit, laser receiving unit, optical fiber for each optical head unit, optical switching device for coupling an optical head unit and a separate laser transmitting unit, and a central control unit, the optical head units connected to the optical switching device through the optical fiber, the optical head units having an optical axis, parallel to which light is emitted or received, and an optical pointing mechanism for adjusting the respective optical axis. The separate laser transmitting unit has a laser. The control unit connects to the optical switching device, laser transmitting unit, laser receiving unit and optical head unit to control a laser based data communication through coupling an optical head unit, which is in a free line of sight to a target outside the aircraft, to the laser transmitting unit and to modulate operation of the laser transmitting unit for emitting a signal.