Methods, systems, and devices for free-space optical communications. An aircraft includes a flat optical communication terminal on an external surface of the aircraft, the flat optical communication terminal being configured to communicate with a ground station via a free-space optical communication link.

A system and method are disclosed for providing a bi-directional data communication link within a LIDAR assembly that has a stationary portion attached to an autonomous vehicle and a second portion rotatably connected to the stationary portion. The second portion may include one or more emitting/receiving devices (e.g., lasers) for detecting objects surrounding the autonomous vehicle. A first printed circuit board assembly (PCBA) having a first optical transceiver may be located within the stationary portion. A second PCBA having a second optical transceiver may be located within the second portion. A hollow shaft may be positioned so as to extend between the stationary portion and the second portion.

A communication device includes an interleaving unit that determines an interleaving length of transmit data to be transmitted through free-space optical communication, and interleaves the transmit data based on the determined interleaving length, and a shaping unit that shapes the interleaved transmit data so as to make the interleaving length detectable on a receiving side of the free-space optical communication.

Proposed is a receiving UE for receiving a signal in optical wireless communication, according to the present disclosure. The receiving UE may include: a transceiver for receiving an optical signal of an orbital angular momentum (OAM) mode from a transmitting terminal; a demodulator composed of at least one phase shifter; a photoelectricity converter composed of at least one photodiode; and a processor connected to the transceiver, the demodulator, and the photoelectricity converter. In addition, the at least one phase shifter may convert an optical signal of the OAM mode into an optical signal of a Gaussian mode, and the at least one photodiode may convert an optical signal of the Gaussian mode into an electrical signal.

A system includes a transmitter configured to output an optical signal. The transmitter includes a seed laser, an optical array including a plurality of array elements, and a plurality of phase shifters in a multi-layer arrangement. The multi-layer arrangement includes a plurality of layers between the seed laser and the optical array, wherein a first layer of the plurality of layers transmits light to a second layer of the plurality of layers. The first layer has fewer phase shifters than the second layer. The multi-layer arrangement also includes a plurality of branches wherein each branch includes a phase shifter from each of the plurality of layers connected in series between the seed laser and one of the plurality of array elements. Each phase shifter is configured to shift the optical signal incrementally to amass a total phase shift for each of the plurality of array elements.

A system for communication is provided. The system includes an emitter transmitting a first code of a first wavelength. The system includes a filter or variable waveplate receiving the first code. The system includes a receiver sensor receiving the filtered first code. The system includes the emitter transmitting a second code of a second wavelength. The system includes the variable waveplate or other filter receiving the second signal. The system includes the receiver sensor receiving the filtered second code. The first and second codes may be used for communication, synchronizing the emitter, and other purposes.

In order to improve free space optical communications, an optical communication terminal includes a laser source, a photo detecting apparatus and an optical input/output assembly. These components are controlled by a control logic. In order to have the optical communication terminal to be self-compatible, the optical input/output assembly selectively routes the outgoing beam and incoming beam depending on their respective beam polarization. To this end, the optical input/output assembly may include a polarizing beam splitter together with a quarter-wave plate.

A method of receiving, by a receiving terminal, a signal in optical wireless communication is proposed. The method may comprise: establishing a communication link for performing the optical wireless communication with a transmitting terminal; receiving an optical signal from the transmitting terminal through the communication link; and performing interference cancelation on the optical signal. Here, establishing the communication link comprises transmitting and receiving initial information with the transmitting terminal, wherein the initial information may include an orbital angular momentum (OAM) mode applied to the optical signal. In addition, the interference cancelation may be performed on the basis of the OAM mode.

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.

Disclosed herein are methods, devices, and system for beam forming and beam steering within ultra-wideband, wireless optical communication devices and systems. According to one embodiment, a free space optical (FSO) communication apparatus is disclosed. The FSO communication apparatus includes a semiconductor optical device configured to have a transient response time of less than 500 picoseconds (ps), a lens, and a first band select filter.