FSO systems rely on line-of-sight, and thus can be easily impaired due to disruptions such as atmospheric turbulence. There is a need for a more robust communication system allowing longer distances to be bridged and/or downtime to be reduced.

An optical transmitter is provided generating at least one optical alignment beam. The transmitter comprises at least one alignment modulator, to modulate the alignment beam with transmitter directional data. A suitable receiver may demodulate this information and use the directional data from the transmitter to simplify the attainment and/or maintenance of a sufficient degree of alignment.

Additionally or alternatively, the at least one alignment beam may be used to detect, characterize and/or monitor one or more environmental parameters.

Embodiments of the present application provide a visible light signal receiving and control method, a control apparatus, and a receiving device. The method comprises: determining a communication performance between a visible light signal receiving device and at least one visible light signal transmit device; and in response to an increase in the communication performance between the visible light signal receiving device and the at least one visible light signal transmit device, combining two first logic pixel units of an image sensor related to the at least one visible light signal transmit device as one second logic pixel unit to be read, when reading an inductive charge of the image sensor of the visible light signal receiving device. The method, apparatus, and device of the embodiments of the present application are capable of reducing power consumption of a visible light signal receiving device by changing the charge readout mode of an image sensor of the visible light signal receiving device in response to a change in the communication performance, and are more suitable for visible light communications in complicated mobile scenarios.

Novel tools and techniques for provisioning a wireless base station functionality at a terminal enclosure are provided. A system includes a first network device, first transceiver, first antenna, second network device, second transceiver, and a second antenna. The first network device may be communicatively coupled to a first network via a first medium and a second medium. The first network device may include a first transceiver coupled to the first network via the first medium, and a first antenna coupled to the first transceiver. The second network device may be coupled to a second network, and include a second transceiver coupled to a second antenna. The first and second network devices may be configured to communicate wirelessly, wherein data communicated from the second network device to the first network device is transmitted to the first network via the first medium.

At a transmitter-side in an optical communication network, pulse amplitude modulation optical signals to be transmitted are pre-compensated using a chromatic dispersion pre-compensation stage and a device non-linearity pre-compensation stage. The non-linearity pre-compensation may be achieved by using look-up tables that are built based on messages exchanged between the transmitter and a target receiver using known symbol patterns.

An example imaging system may include a spatial light modulator and a coherent optical receiver. The spatial light modulator may be configured to receive an optical input wave and perform wavefront shaping on the optical input wave to output a shaped wave. The coherent optical receiver may include an optical local oscillator, an optical beam splitter, an optical detector, and processing circuitry. The optical detector may be configured to receive a mixed wave from the optical beam splitter that is based on the mixing of a local oscillator wave with a scattering medium output wave that at least initially comprises a speckle pattern formed by the shaped wave interacting with a scattering medium. The processing circuitry may be configured to perform coherent detection on the mixed wave to extract optical amplitude and phase information, and provide an error signal as feedback to the spatial light modulator for performing iterative wavefront shaping.

It is difficult in a free space optical receiver to satisfy both of the stable receiving and the highly sensitive receiving; therefore, a free space optical receiver according to an exemplary aspect of the present invention includes a light collecting means for collecting laser light having propagated through a free space transmission path; a multimode light generating means for receiving input of the laser light collected by the light collecting means, exciting multimode light, and outputting multimode propagation light including a plurality of propagation mode light beams with a number smaller than a number of multimode light beams possible to be excited; and a mode separating means for separating the multimode propagation light into the plurality of propagation mode light beams and outputting the plurality of propagation mode light beams.

Aspects are generally directed to receivers and methods for actively demodulating optical signals. In one example, a receiver includes an optical resonator to receive an optical signal, the optical resonator including an active optical medium interposed between first and second semi-reflective surfaces, where the active optical medium is configured to accumulate resonant optical signal energy inside the optical resonator based on the received optical signal, the second semi-reflective surface is positioned to emit output optical signal energy, and the optical resonator is configured to disturb the output optical signal energy in response to a variation in the received optical signal. The receiver may further include a detector configured to detect the disturbance in the output optical signal energy, and a pump source coupled to the active optical medium to excite the active optical medium to generate an optical gain in the received optical signal.

Optical signal receivers and methods are provided that include multiple optical resonators, each of which receives a portion of an arriving optical signal. Various of the optical resonators are tuned or detuned from a carrier wavelength, and produce an intensity modulated output signal in response to modulation transitions in the arriving optical signal. A detector determines modulation transitions in the arriving optical signal by analyzing the intensity modulation output signals from the optical resonators.

A SDH receiver which comprises a first polarization beam splitter 11, a second polarization beam splitter 13, a first separator 15, a second separator 17, a third separator 19, a fourth separator 21, a first 90-degree polarization rotor 23, a second 90-degree polarization rotor 25, a first hybrid detector 31, a second hybrid detector 33, a third hybrid detector 35, a fourth hybrid detector 37, and a signal processor 39.

An optical modulator connected to a first optical fiber and a second optical fiber arranged in parallel includes an optical-path changing unit that redirects light emerging from a tip of the first optical fiber toward a tip of the second optical fiber and an optical modulation chip that modulates the light redirected by the optical-path changing unit and outputs a light beam obtained by modulating the light to a tip of the second optical fiber.