A free space optical FSO space data transmission system includes a first ground or aeronautical optical terminal, a second optical terminal housed on board a satellite, and a relay platform. The relay platform is configured so as to move at an altitude higher than that of clouds and atmospheric turbulence, so as to receive the data transmitted by the first terminal in the MWIR/LWIR domain of long wave infrared LWIR wavelengths and/or medium wave infrared MWIR wavelengths, and retransmit the received data to the second terminal in the domain of short wave infrared SWIR wavelengths, and/or receive the data transmitted by the second terminal in the domain of short wave infrared SWIR wavelengths, and retransmit the received data to the first terminal in the MWIR/LWIR domain of long wave infrared LWIR wavelengths and/or medium wave infrared MWIR wavelengths.

Techniques disclosed herein relate to adjusting parameters that impact reliability of free space optics (“FSO”) between stationary fixtures. In various embodiments, a street lamp FSO system may include: motion sensor(s) (104, 204) to detect motion at location(s) of a street lamp (210); local FSO component(s) (108, 208) for deployment on the street lamp; and logic (102) to: receive first samples indicative of first motion of a first portion of the street lamp relative to abase (214) of the street lamp from the motion sensor(s); analyze the first samples to generate and store a reference motion profile for future use; receive second samples indicative of second motion of the street lamp from the motion sensor(s); compare the second samples with the reference motion profile; and based on the comparison, take action(s) to maintain a FSO communication beam between the local FSO component(s) and a remote FSO component.

An underwater wireless optical communication, UWOC, unit (30) for underwater deployment on a submerged earth layer (12) or structure (14, 16). The UWOC unit is configured for wireless optical communication in an underwater environment, and comprises an optical transmitter (36), an anidolic optical receiver (38), and a processor (44). The optical transmitter is configured to transmit data by emitting an optical signal (80) into the surroundings. The optical receiver includes an optical detector (62), which is omnidirectionally sensitive and configured to receive further optical signals approaching substantially along an azimuthal plane orthogonal to a nominal axis (A) through the UWOC unit. The processor is coupled to the optical receiver, and configured to process received further optical signals.

The unit may be configured to determine an inter-unit distance between this unit and a second unit, by sending an optical interrogation signal to the second unit, and receiving an optical response signal from the second unit.

An assembly for optical to electrical power conversion including a photodiode assembly having a substrate layer and an internal side, an antireflective layer, a heterojunction buffer layer adjacent the internal side; an active area positioned adjacent the heterojunction buffer layer, a plurality of n+ electrode regions and p+ electrode regions positioned adjacent the active area, and back-contacts configured to align with the n+ and p+ electrode regions. The active area converts photons from incoming light into liberated electron hole pairs. The heterojunction buffer layer prevents electrons and holes of the liberated electron hole pairs from moving toward the substrate layer. The plurality of electrode regions are configured in an alternating pattern with gaps between each n+ and p+ electrode region. The electrode regions receive and generate electrical current from migration of the electrons and the holes, provide electrical pathways for the electrical current, and provide thermal pathways to dissipate heat.

Techniques are described for relaying of high-band radiofrequency communications through a window that would otherwise partially or completely block the communications. For example, embodiments include a pair of high-band-to-optical (HB2O) relays mounted on either side of a window. One of the relays receives a high-band radiofrequency (HB-RF) communication signal that is unable to pass through the window and converts the HB-RF communication signal to an optical communication signal. As the window is substantially transparent to visible-spectrum light, the optical communication signal can pass through the window. The optical communication signal is transmitted through the window to the other HB2O relay, and the other HB2O relay converts back to a HB-RF communication signal. Thus, HB-RF networks on either side of the window can be communicatively coupled via the optical communications provided by the pair of relays.

Optical communication with a remote node comprises: transmitting at least one optical beam to the remote node; receiving at least a portion of at least one optical beam from the remote node; providing intensity information based on one or more signals from one or more optical detector modules in an array of optical detector modules detecting the portion of the optical beam received from the remote node; and controlling at least one optical phased array to steer the optical beam transmitted to the remote node based on intensity information received from the remote node.

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.

A sensor circuit (10), including a silicon photomultiplier, SiPM, sensor (20), a voltage source (32), a current-to-voltage converter (24), and a limiting bias circuit (34). The SiPM sensor (20) has avalanche photodiode, APD, elements (30) connected in parallel between a cathode (K) and an anode (A). The voltage source (32) is configured to apply a reversed bias voltage (Vb) across the SiPM sensor, so that each APD element operates in reverse-biased Geiger mode, and the APD elements operate in integration mode. The bias circuit (34) is connected between the voltage source (32) and the anode, and is configured to limit currents through the APD elements, and to present an AC load impedance for an alternating current within a predetermined operating frequency range (fo) generated by the APD elements at the anode (A) as well as a DC load impedance, such that said AC load impedance is lower than said DC load impedance.

The disclosure provides for a system that includes a network controller. The network controller is configured to receive information from nodes of a network, where nodes include one node that is in motion relative to another node. The network controller is also configured to generate a table representing nodes, available storage at each node, and possible links in the network over a period of time based on the information, and determine a series of topologies of the network based on the table. Based on received client data including a data amount, the network controller is configured to determine flows for the topology. The network controller then is configured to generate a schedule of network configurations based on the flows, and send instructions to the nodes of the network for implementing the network configurations and transmitting client data.

Techniques are disclosed for aligning an optical transmitter with an optical receiver for a line-of- sight communications link, wherein the optical transmitter comprises a laser array emitter, the laser array emitter comprising a plurality of laser emitting regions, wherein each of a plurality of the laser emitting regions is configured to emit laser light in a different direction such that the laser array emitter is capable of emitting laser light in a plurality of different directions. The system can run produce emissions from different laser emitting regions until a laser emitting region that is in alignment with the optical receiver is found. This aligned laser emitting region can then be selected for use to optically communicate data from the optical transmitter to the optical receiver.