This invention pertains to the field of free-space optical (FSO) communications, and specifically to the realization of functional FSO optical transceiver terminals located at remote electrically unpowered locations within a communications network. A remote unpowered FSO terminal located at a far-end location receives necessary optical power from a powered base station location (near-end) required for all optical amplification functions necessary for NRZ or RZ format signals within the spectral range of 900 nm to 1480 nm as well as an Ultra Short Pulsed Laser (USPL) centered at 1560 nm at the far-end location. A transmitting node identified as the near-end transmits an optical signal identified as a pump signal to a remote location classified as the far-end node over a free space medium, such as the atmosphere, where the far-end node location does not have available electrical power for operation of electro-optic components required for transmission and retransmission functions.

An example apparatus includes a first communications module having a first transceiver. The first communications module is operable to transmit, using the first transceiver, a plurality of first groups of optical subcarriers to a plurality of second communications modules via free-space optical communication. The first groups of optical subcarriers carry first data, and each of the first groups of optical subcarriers is associated, respectively, with a different one of the second communications modules. The first communications module is also operable to receive, using the first transceiver, plurality of second groups of optical subcarriers from the second communications modules via free-space optical communication. The second groups of optical subcarriers carry second data and each of the second groups of optical subcarriers is associated, respectively, with a different one of the second communications modules.

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.

A first resistor connected in parallel to a semiconductor optical modulator having first ends, the first resistor and first ends connected to a reference potential. A first end of a first transmission line is connected to second ends of the semiconductor optical modulator and the first resistor. A second transmission line is connected in series to the first transmission line and has an impedance lower than that of the first resistor. A first end of the second transmission line is connected to a second end of the first transmission line. A third transmission line is connected in series to the first and second transmission lines and has an end connected to a second end of the second transmission line, and has an impedance equal to that of the first transmission line. A second resistor and a capacitor are connected in series between the third transmission line and the reference potential.

A multimode coupling fiber for optical data links features low coupling loss to silicon photonics lasers, VCSELs, single mode transmission fibers, multimode transmission fibers, and high speed receivers. The coupling fiber includes a core, an optional inner cladding region, a depressed index cladding region, and an outer cladding region. The relative refractive index profile of the coupling fiber includes a core region with α profile and a depressed index cladding region that facilitates low bending loss and high bandwidth. The mode field diameter of the coupling fiber is well-matched to standard single mode transmission fibers and the etendue of the coupling fiber is high enough to couple efficiently to multimode transmission fibers.

An optical communication device is configured to include: a laser diode that outputs light; an EA modulator including a cathode and an anode, to modulate the light output from the laser diode on the basis of a high-frequency signal applied between the cathode and the anode; a resistor connected between the cathode and the anode; and a pattern line connected in series with the resistor and having an inductance component, in which each of the laser diode and the EA modulator is formed on a front surface of the high-frequency line substrate or a back surface of the high-frequency line substrate, and the pattern line is formed on a side face of the high-frequency line substrate.

A transmission device of the present disclosure is a transmission device that transmits a visible light signal to a receiving device, and includes a laser light source configured to emit visible light, and an optical modulator configured to change intensity of the visible light and generate a visible light signal, in which the optical modulator has an optical waveguide that serves as a transmission path for the visible light, and the optical waveguide is formed of a material containing lithium niobate.

A system to program parameters of one or more stages of a transimpedance amplifier (TIA) in an optical sub-assembly (e.g. TO-can package) is disclosed. With this invention, users have the option/flexibility to discretely program any of the stages of the TIA after production of the sub-assembly, i.e. they can still change the TIA settings once the TIA has been installed in a system and the system is in use.

A transmitter can include a laser operable to output an optical signal; a digital signal processor operable to receive data and provide a plurality of electrical signals based on the data; and a modulator operable to modulate the optical signal to provide a plurality of optical subcarriers based on the plurality of electrical signals. One of the plurality of subcarriers carries first information indicative of a first portion of the data in a first time slot and second information indicative of a second portion of the data in a second time slot. The first information is associated with a first node remote from the transmitter and the second information is associated with a second node remote from the transmitter. A receiver as well as a system also are described.

A laser relay module in a free space optical communication network includes: a beacon source for generating an optical beacon signal for aligning a communication channel of a source optical node to a communication channel of a receiving optical node; a beacon inserter for encoding the optical beacon signal with switching information; a telescope for transmitting the encoded optical beacon signal to the receiving optical node; a beacon detector for detecting received switching information from the modulated optical beacon signal, wherein the receiving optical node uses the encoded optical beacon signal to align communication channel of the receiving optical node with communication channel of the source optical node; and a processor for using the detected switching information to change configuration of an optical switch matrix to direct received data to a next optical node in the free space optical communication network.