An optical receiver module which receives a first optical signal including a continuous signal or a burst signal includes: a variable optical attenuator which adjusts the first optical signal to output a second optical signal; a semiconductor optical amplifier which amplifies the second optical signal to output a third optical signal; and a controller which controls an output of at least one of the variable optical attenuator and the semiconductor optical amplifier so as to cause the semiconductor optical amplifier to operate in a region in which gain saturation of the semiconductor optical amplifier does not occur, on the basis of at least one of: a power obtained by suppressing an outside portion of the wavelength band of the first optical signal in the third optical signal; and a power obtained by extracting the outside portion of the wavelength band of the first optical signal in the third optical signal.

An FSO communication system includes a laser, an optical detector and a first optical adjustment module and a controller. The laser is configured to emit an optical signal. The optical detector is configured to receive an optical signal from the first optical adjustment module. The controller is configured to obtain an optical power of an optical signal received by the optical detector; and generate a control command based on the optical power and transmit the control command. The first optical adjustment module is configured to: receive the control command and the optical signal emitted by the laser; adjust, in response to the control command, the optical signal emitted by the laser to cause the optical power of the optical signal received by the optical detector to be in a preset reasonable range; and transmit the adjusted optical signal to the optical detector.

A visible light communication (VLC) optical receiver (100) is provided, the receiver (100) includes a photodetector; and a modified Fresnel lens (103), characterised in that the lens (103) is curved into a convex shape such that multiple focal points (110) are created when light from a light source is diffracted through the lens (103) allowing the light signal to be received by the photodetector at the different positions of the photodetector corresponding to said focal points.

A signal processing device processes reception signals of optical signals received by a receiver when the optical signals transmitted from a transmitter are propagated to the receiver via a plurality of paths, and includes: a signal-to-noise ratio calculating unit that calculates signal-to-noise ratios of the optical signals that have been propagated through the respective paths, from propagation distances of the optical signals in the respective paths, intensities of the optical signals transmitted from the transmitter, and intensities of noise with respect to the optical signals transmitted from the transmitter; an amplitude adjusting unit that adjusts amplitudes of the reception signals of the optical signals that have been propagated through the respective paths, using the corresponding signal-to-noise ratios calculated by the signal-to-noise ratio calculating unit; and a signal combining unit that combines the reception signals whose amplitudes have been adjusted by the amplitude adjusting unit.

A system and method for providing optical multiple input and multiple output data communication using optical signals includes a plurality of light sources, a plurality of photodetectors, and at least one controller. The plurality of light sources are configured to emit optical signals to communicate data. The plurality of photodetectors are configured to sense the optical signals, and are embedded in at least one receiver. At least one of the plurality of photodetectors is configured to receive the optical signals from two or more of the plurality of light sources. The controller is configured to assign a transmit power to at least some of the plurality of light sources based on parameters of the plurality of photodetectors.

Disclosed is network management technology for an optical line terminal. The optical line terminal allocates a line identifier according to a line length from each port to an end thereof. Terminal connection information is managed such that a corresponding line identifier is mapped to a measured line length to an optical network terminal. Service settings for an optical network terminal are managed by the line identifier.

An optical circuit breaker includes a main optical transmission path including an optical coupler, a delay line and a protection device, and a parallel protection path configured to receive a tapped portion of a signal provided to the main optical transmission path and generate a reference signal based on the tapped portion. The protection device may be configured to be triggered to prevent an overpower condition from passing through the optical circuit breaker responsive to the reference signal exceeding a user selectable threshold. The delay line may be configured to have a longer delay than a time it takes for the protection device to be triggered via the parallel protection path.

An optical interconnect computing module having free space optical interconnects that form communication links with other systems with like optical interconnects and with computer blades contained within the computing module. The computing module adapts to changes in the position and orientation and other factors of the optical interconnects. The optical interconnects utilize solid-state electronic and optoelectronic components and optical components. The ability to adapt is controlled by an algorithm implemented in software, firmware and logic circuits. Computing modules within an equipment rack and between equipment racks as well as blades contained within a computing module may experience changes in position and orientation due to installation misalignment, servicing of equipment, vibrations, floor sagging, thermal expansion and contraction, earthquakes, line-of-sight obstructions, manufacturing imperfections and other sources.

An FSO communication system includes a laser, an optical detector and a first optical adjustment module and a controller. The laser is configured to emit an optical signal. The optical detector is configured to receive an optical signal from the first optical adjustment module. The controller is configured to obtain an optical power of an optical signal received by the optical detector; and generate a control command based on the optical power and transmit the control command. The first optical adjustment module is configured to: receive the control command and the optical signal emitted by the laser; adjust, in response to the control command, the optical signal emitted by the laser to cause the optical power of the optical signal received by the optical detector to be in a preset reasonable range; and transmit the adjusted optical signal to the optical detector.

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.