A dual-mode imaging receiver (DMIR) can acquire and maintain SOA free-space optical communication (FSOC) links without a precision mechanical gimbal. Unlike other FSOC technologies, a DMIR can operate without precise spatial alignment and calibration of the transmitter's or receiver's spatial encoders (precision pointing) in static (fixed point to point) geometries. Instead, a DMIR uses electronic receive beam selection to acquire and track transmitters with coarse mechanical pointing and a single aperture. And because the DMIR can operate with just one aperture, it does not need a beacon at the transmitter since it does not transition from a wide field-of-view acquisition aperture to a narrow field-of-view detection and decoding aperture even in dynamic geometries.

The system and method for frequency encoded beacons for use in covert dismount identification, friend or foe and communications. Waveforms are capped at thresholds below human and conventional night vision detection. Waveforms are further modulated to identify dismounts as well as other information such as day and time, rank, health status, and the like. The beacons may operate at different wavelengths depending on whether they are used on ground, in air, or at sea.

Free space optical communication is plagued by interruptions in the connections caused by atmospheric phenomena, such as weather. A wireless beam transmission system includes at least one transmitter (110) and accommodates several wavelengths, and at least one transmission wavelength is arranged to be chosen based on spectral absorption measurements of the atmosphere in the carrier beam path of communication. The invention concerns also a transceiver for repeating wireless optical communication signals. The long range and high reliability of spectroscopically sensitive light beams at a penetrating frequency allow the affordable provisioning of high bandwidth optical or IR communication connections to devices and buildings that were previously either very expensively connected to the fiber optic backbone networks, expensive low bandwidth radio or microwave networks, or unreachable by traditional free space optics solutions.

A communication device can achieve SN ratio and stability of signal output an optical transmission line having the propagation characteristics susceptible to environmental changes. The communication device includes: an optical reception section configured to receive weak signal light and reference light arriving through the optical transmission line; an optical amplifier that amplifies received reference light; a probe light receiver that receives probe light arriving from the transmitting-side communication device through the optical transmission line; and a controller configured to calculate a transmission line state detected based on received probe light and control a gain of the optical amplifier according to the transmission line state.

The present disclosure provides systems and methods for enabling Personal Augmented Reality (PAR). PAR can include an emitor configured to receive data signals and emit the data signals as light signals. PAR can further include a smart device configured to receive the light signals emitted by the emitor. The smart device can process the light signals to yield a communication and display the communication on a screen.

In some embodiments, an optical communication system may include an optical source, a modulator, and a photoreceiver. The optical source may be configured to generate a beam comprising a series of light pulses each having a duration of less than 100 picoseconds. The photoreceiver may have a detection window duration of less than 1 nanosecond. When a first pulse travels through a variably refractive medium, photons in the first pulse may be refracted to travel along different ray paths to arrive at the photoreceiver according to a temporal distribution curve. A full width at half maximum (FWHM) value of the temporal distribution curve may be at least three times as large as a coherence time value of the first pulse, and the detection window of the photoreceiver may be at least six times as large as the FWHM value of the temporal distribution curve.

Systems, devices, and methods for laser-based communications are disclosed. At least one embodiment relates to laser-mediated underwater communications, in which one or more laser signals transmit encoded information from a transmitter to a receiver. Additionally, an underwater transmitter node sends information to an underwater receiver node using one or more lasers. At least an additional embodiment relates to laser-based communications that may be used to send information across a variety of media (e.g., air, water, etc.). Specifically, a first and a second communications system each sends a laser beam to the other. Each communications system further includes a position sensitive detector (PSD) that obtains positioning and/or steering information of an incoming laser beam and ensures that the positions of both the outgoing laser beam and the incoming laser beam match.

An optical wireless communication (OWC) system comprises: a multiple input multiple output (MIMO) device configured to provide a plurality of signals each representing a respective data stream; conditioning circuitry configured to receive the plurality of signals from the MIMO device and process the plurality of signals to produce at least one conditioned signal representative of the data stream(s) and suitable for transmission using an OWC transmission device; an OWC transmission device comprising at least one transmitter for transmitting light and configured to be responsive to the at least one conditioned signal to transmit light representative of the data stream(s) using the at least one transmitter.

To provide a free space optical communication apparatus with an increased efficiency of optical axis alignment. A free space optical communication apparatus (1) includes: light transmitting sections (10); and an optical axis alignment section (20) configured to align an optical axis of each of the light transmitting sections (10) with a corresponding one of light receiving sections (130) included in a communication target. The optical axis alignment section (20) causes at least one of the light transmitting sections (10) to emit scan light (3) while varying an emitting direction, and aligns an optical axis of a light transmitting section (10) which is other than the at least one light transmitting section (10), based on an emitting direction of the scan light (3) emitted from the at least one light transmitting section (10) and received by a corresponding one of the light receiving sections (130).

A free-space optical (FSO) terminal may include a controller and an alignment sensor. The alignment sensor includes a set of detectors. Each detector generates a signal responsive to receiving electromagnetic radiation at a detection surface. The set of detectors includes an inner set of detectors and an outer set of detectors. The detection surfaces of the inner detectors and the outer detectors may be aligned in a plane. The outer set of detectors surround the inner set of detectors (e.g., in the plane) and have larger detection surfaces than the inner set of detectors. During a tracking mode, the controller is configured to adjust an orientation of the FSO terminal based on signals from the inner set of detectors. During an acquisition mode, the controller is configured to adjust the orientation of the FSO terminal based on signals from the outer set of detectors.