A directional free-space optical communication system includes a source device including a laser diode and an endpoint device including a photodiode. The endpoint device and the source device also include an adjustable optics subsystem that increases both angular and positional offset tolerance between the source device and the endpoint device.

Traditional satellite-to-earth data transmission systems are constrained by inefficient relay schemes and/or short-duration data transfers at low data rates. Communication systems described herein achieve extremely high burst rate (e.g., 10 Gbps or greater) direct-to-Earth (DTE) data transmission over a free-space optical link between a spacecraft and a remote terminal, which may be a ground terminal or another space terminal. The optical link is established, for example, when the remote terminal is at an elevation of 20 with respect to a horizon of the remote terminal. In some embodiments, a data transmission burst contains at least 1 Terabyte of information and has a duration of 6 minutes or less. The communication system can include forward error correction by detecting a degradation of a received free-space optical signal and re-transmitting at least a portion of the free-space optical signal.

The present invention provides a free space optical communication system that uses orthogonal modes of aberration in a laser beam as means for encoding the information. The system comprises a transmission station which transmits the user defined information in terms of the amplitudes of certain orthogonal aberration modes present in the transmitted beam. The beam then travels through free space before it reaches the receiving station. The receiving station comprises a high speed wavefront sensor of light beams. The wavefront sensor measures the amplitudes of various orthogonal aberration modes present in the incident beam at different instants of time. The amplitudes of the orthogonal modes at a certain regular time interval are then used to extract the user information.

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.

The disclosed systems, apparatuses and methods are directed to controlling optical channel signal and an optical network equipment in optical networks. The methods comprise adjusting an optical channel spectrum based on bit error rates (BER) measured for a dithered optical channel signal. The optical channel spectrum is dithered such that a signal reference frequency is alternated between a first second signal reference frequency and a second signal reference frequency. BER is measured and analysed separately for the dithered signal reference frequency being detuned to the first and to the second signal reference frequencies. Based on a BER difference between BER at the first signal reference frequency and BER at the second signal reference frequency, the optical channel spectrum is shifted with regards to frequency in order to improve optical network performance.

Enhancements in optical beam propagation performance can be realized through the utilization of ultra-short pulse laser (USPL) sources for laser transmit platforms, which are can be used throughout the telecommunication network infrastructure fabric. One or more of the described and illustrated features of USPL free space-optical (USPL-FSO) laser communications can be used in improving optical propagation through the atmosphere, for example by mitigating optical attenuation and scintillation effects, thereby enhancing effective system availability as well as link budget considerations, as evidenced through experimental studies and theoretical calculations between USPL and fog related atmospheric events.

A transmitter for an optical free-beam communication system includes two light transmitters for the optical transmission of a data signal using one single-sideband modulation, wherein each light transmitter emits a side of the band modulation so that a light signal arriving at a receiver corresponds to a double-sideband modulation.

A method supported by a first terminal is provided herein. To implement the method, a camera of a first terminal performs two or more captures of two or more frames along a line of sight toward a second terminal. A controller of the first terminal manipulates the two or more frames to produce two or more interim images and analyzes the two or more interim images to track a beacon of the second terminal. The controller outputs coordinates with respect to the tracked beacon to a mirror package of the first terminal.

A space optical coupling apparatus, including M first couplers, a phase adjustment apparatus, N beam splitters, M second couplers, a coupling apparatus, and a controller. The first coupler receives a beam, and couples the beam to the phase adjustment apparatus. The phase adjustment apparatus includes M phase adjusters, N beam splitters, and N detectors. Each beam splitter is configured to split a received beam into two beams, one sent to a corresponding detector and the other sent to a corresponding phase adjuster. The second coupler receives output light from the coupling apparatus, and transmits the output light into the space. The coupling apparatus is configured to couple a beam onto a single-mode fiber. The controller is configured to control, based on the beam intensity detected by the detector and the beam intensity on the single-mode fiber, the M phase adjusters to adjust the phases of the received beams.

The disclosed system may include (1) an optical element that receives an optical beam, (2) a wide field-of-view (FOV) quadrant photodetector that receives, from the optical element, first light originating from the optical beam, (3) a narrow FOV quadrant photodetector that receives, from the optical element, second light originating from the optical beam, and (4) a controller that controls an orientation of the optical element during at least a period of time based on a weighted combination of (a) output of the wide FOV quadrant photodetector in response to the first light, and (b) output of the narrow FOV quadrant photodetector in response to the second light. Various other systems, methods, and computer-readable media are also disclosed.