A satellite in low-Earth orbit (LEO) or medium-Earth orbit (MEO) with a modern image sensor and/or other remote sensing device can collect data at rates of 10 Mbps or higher. At these collection rates, the satellite can accumulate more data between its passes over a given ground station than it can transmit to the ground station in a single pass using radio-frequency (RF) communications. Put differently, the sensors fill the spacecraft's memory faster than the spacecraft can empty it. Fortunately, free-space optical communications signals can carry far more data than RF communications signals. In particular, a spacecraft can transmit over 1 Tb of data in a single pass using burst wavelength-division multiplexed (WDM) optical signals. Each burst may last seconds to minutes, and can include tens to hundreds of WDM channels, each of which is modulated at 10 Gbps or more.

A system and method for wavefront correction is achieved using an adaptive optics photonic integrated circuit with monitoring per stage. The method begins with receiving a single optical data signal contained in a distorted wavefront, wherein a single optical signal is divided into a plurality of parts, each representing a unique propagation path through free space, wherein the plurality of parts of the single optical signal is received by a programmable optical processor consisting of cascaded Mach-Zehnder Interferometers (MZi) each with a first phase shifter and a second phase shifter. Next, the settings are adjusted of each of the first phase shifter and the second phase shifter until the plurality of parts of the single optical signal are combined into one output of a last MZi, wherein the settings of the first phase shifter and the setting of the second phase shifter of each MZi are controlled by independent measurements.

A position measuring apparatus instructs a first node to emit light by transmitting a first light emission pattern to the first node, instructs a second node to emit light by transmitting the first light emission pattern to the second node, when light emission following the instructed first light emission pattern is detected, and instructs the second node to emit light by transmitting a second light emission pattern that is different from the first light emission pattern, when light emission following the instructed first light emission pattern is not detected.

Optical communication systems and methods using coherently combined optical beams are disclosed. A representative system includes a first data source for sending first data at a first frequency of a first optical beam to a first aperture, and at a second frequency of a second optical beam to a second aperture. The system further includes a second data source for sending second data at a third frequency of a third optical beam to the first aperture, and at a fourth frequency of a fourth optical beam to the second aperture. The system also includes a first interleaver of the first aperture configured to interleave the first data at the first frequency and the second data at the third frequency; and a second interleaver of the second aperture configured to interleave the first data at the second frequency and the second data at fourth frequency.

Systems and methods are described for transmitting information optically. For instance, a system may include an optical source configured to generate a beam of light. The system may include at least one modulator configured to encode data on the beam of light to produce an encoded beam of light/encoded plurality of pulses. The system may include a spectrally-equalizing amplifier configured to receive the encoded beam of light/encoded plurality of pulses from the at least one modulator and both amplify and filter the encoded beam of light/encoded plurality of pulses to produce a filtered beam of light/filtered plurality of pulses, thereby spectrally equalizing a gain applied to the encoded beam of light. In some cases, the system may slice the beam of slight, to ensure a detector has impulsive detection. In some cases, the system may include a temperature controller to shift a distribution curve of wavelengths of the optical source.

A free-space optical communication method is provided. The method includes generating, at a transmitter of a satellite, an optical frequency comb and a pump signal, modulating the optical frequency comb to generate a data signal and an idler signal that is a phase conjugate of the data signal, attenuating the pump signal, transmitting over free-space, from the satellite, a communication signal having the data signal, the idler signal and the pump signal, receiving from the satellite, at a receiver, the transmitted communication signal having the data signal, the idler signal, and the attenuated pump signal, amplifying, at a phase-sensitive amplifier, the data signal and the idler signal, and demodulating the data signal and the idler signal to extract data.

Described herein are ground based subsystems, and related methods, for use in transmitting an optical feeder uplink beam to a satellite that includes a multiple element antenna feed array and that is configured to accept the optical feeder uplink beam and in dependence thereon use the multiple element antenna feed array to produce and transmit a plurality of radio frequency (RF) service downlink beams to service terminals. Certain embodiments are related to a ground based beamformer (GBBF) for inclusion in a ground based subsystem, and methods for use therewith. Beneficially, embodiments described herein allow for flexible antenna beam forming for large signal bandwidth without the limitation associated with the available gateway uplink and downlink spectrum at RF frequencies. Also described herein are space based subsystems for use with such ground based subsystems.

A method for wireless data transmission between a first communication device and a second communication device, wherein the first communication device acts as a data source and the second communication device acts as a data sink, includes: splitting, by the data source, data to be transmitted from the data source to the data sink into a carrier signal for a radio channel and an optical carrier signal by modulating the carrier signals; transmitting the data via a hybrid transmission path from the data source to the data sink by simultaneously transmitting some of the data via the radio channel and some of the data via a wireless optical direct channel; and merging, by the data sink, via a demodulation process, the data transmitted via the radio channel and the data transmitted via the wireless optical direct channel.

Precision docking is one of the most important tasks for drones and surface robots to charge themselves and load/unload packages. Without accurate docking, surface robots and drones will miss their charging pad or charging contacts and cannot automatically charge themselves for later tasks. Described is a system using coded light to guide the precision docking process for drones and ground robots. More specifically, the system uses projectors to project temporal identifiers for space partitioned by pixel projections. Different space partition gets a different identifier. By using a simple light sensor on a drone or a ground robot, the drone or the ground robot can know its precise location in the space and therefore knows where to move for a precise docking. Depending on docking precision requirement, the coded light precision may be adjusted by using projectors with different resolutions.

A system includes a transmitter with multiple transmit devices each having an OAM multiplexer that converts multiple input signals into an OAM beam. Each transmit device outputs a coaxial group of orthogonal OAM beams. The system also includes a receiver that has multiple receive devices each having an OAM demultiplexer that receives the group of OAM beams from a corresponding transmit device. The OAM demultiplexer also converts the coaxial group of mutually orthogonal OAM beams into a plurality of received signals corresponding to input signals represented by the OAM beams. The receiver also includes a MIMO processor that has an equalizer that determines a transfer function corresponding to crosstalk of each of the plurality of received signals. The MIMO processor also reduces the crosstalk of each of the plurality of received signals based on the transfer function and updates the transfer function.