An optical communication system using a photonic lantern for fine point tracking is disclosed. The optical communication system may comprise a photonic lantern, a signal processing unit including one or more fiber splitters to sample a fraction of a received signal in each single mode fiber of the photonic lantern, and one or more intensity sensors positioned in one arm of each fiber splitter, and used for monitoring fiber-specific intensity data associated with each of the single-mode fibers. The system may further include a fine pointing assembly and a controller for controlling a driver of the fine pointing assembly.

An optical transmission/reception unit includes a carrier rotatable around an axis of rotation, an optical receiver arranged at the carrier on the axis of rotation so as to receive an optical reception signal from a first direction, an optical transmitter arranged at the carrier adjacent to the optical receiver so as to emit an optical transmission signal in a second direction, and a transmission/reception optic arranged at the carrier on the axis of rotation above the optical receiver and extending across the optical receiver and the optical transmitter, wherein the transmission/reception optic includes a reception optic and a transmission optic arranged in the reception optic, wherein the reception optic is configured to guide the optical reception signal striking the transmission/reception optic towards the optical receiver on the axis of rotation.

An optical communication system which is tunable and polarization insensitive is provided herein. The optical communication system may comprise an optical bench coupling an optical transmit pathway and an optical receiving pathway to an external pathway. The optical bench includes a polarization insensitive optical circulator. The system may further include a tunable component positioned along the optical receiving pathway, and a controller coupled to the tunable component.

The disclosure provides for a free-space optical communication system that includes a first lens group, a field corrector lens, and a second lens group. The first lens group is configured to receive light received from a remote free-space optical transmitter. The first lens group has a first focal plane. The field corrector lens is positioned between the first lens group and the first focal plane of the first lens group and positioned closer to the first focal plane than the first lens group. The first lens group also is made of material having an index of refraction of at least 2.0, and has a second focal plane. The second lens group is positioned at the second focal plane of the field corrector lens and is configured to couple light to a sensor.

Methods and systems are described for free space optical communication. An example device may comprise an optical beam separator configured to separate a first optical path into a receiving (Rx) optical path for signals received from free space and a transmitting (Tx) optical path for signals being transmitted into free space. The example device may comprise at least one positioner coupled to one or more of the Rx optical path or the Tx optical path. The example device may comprise a controller configured to control the at least one positioner to adjust one or more of the Rx optical path or the Tx optical path to facilitate communication with a remote communication device via free space.

A control device includes: a control signal transmitter transmitting a signal to a controlled device; a control signal receiver receiving a signal from the controlled device; a control signal generator generating a control signal of 2 bytes or more in one transmission cycle, in which an address is assigned to each byte, is ON/OFF switchable, and includes a main signal address and a collation signal address; and a control signal controller that, when the main and collation signal addresses are the same address, turns the collation signal address ON when the main signal address is ON and turns the collation signal address OFF when the main signal address is OFF, and when the main and collation signal addresses are inverted, turns the collation signal address OFF when the main signal address is ON and turns the collation signal address ON when the main signal address is OFF.

An OAM multiplexing communication system uses one or more OAM modes and multiplexes signals of one or more sequences for each OAM mode. A transmitting station includes a transmitting antenna using an M-UCA, and an OAM mode generation unit that simultaneously generates one or more OAM modes from each UCA. A receiving station includes a receiving antenna equivalent to the M-UCA, an OAM mode separation unit that separates signals received by each UCA for each OAM mode, and a received signal processing unit that estimates channel information for each OAM mode and performs an equalization process for each OAM mode by using a receiving weight calculated from the channel information. The received signal processing unit is configured to estimate, for each OAM mode, channel information of another OAM mode causing interference and calculate the receiving weight of a subject OAM mode by using the channel information of the subject OAM mode and said another OAM mode.

An apparatus includes multiple dual cladding waveguides each having a single-mode interior section that transports one of multiple outgoing optical signals and a multimode section at least partially surrounding the interior section that transports one of multiple incoming optical signals. Different outgoing signals have different polarizations, and different incoming signals have different polarizations. The apparatus also includes a polarization beamsplitter that combines the multiple outgoing signals to produce transmit optical signals and separates receive optical signals to produce the multiple incoming signals.

A system includes an optical transceiver configured to transmit and receive optical signals. The optical transceiver includes a Faraday rotator and a waveplate. The Faraday rotator and the waveplate are collectively configured to provide a relative polarization change between (i) light propagating in a first direction through the Faraday rotator and the waveplate and (ii) light propagating in a second direction opposite the first direction through the Faraday rotator and the waveplate. The waveplate may include a quarter waveplate or a half waveplate.

A control device includes: a control signal transmitter transmitting a signal to a controlled device; a control signal receiver receiving a signal from the controlled device; a control signal generator generating a control signal of 2 bytes or more in one transmission cycle, in which an address is assigned to each byte, is ON/OFF switchable, and includes a main signal address and a collation signal address; and a control signal controller that, when the main and collation signal addresses are the same address, turns the collation signal address ON when the main signal address is ON and turns the collation signal address OFF when the main signal address is OFF, and when the main and collation signal addresses are inverted, turns the collation signal address OFF when the main signal address is ON and turns the collation signal address ON when the main signal address is OFF.