The present disclosure generally pertains to systems and methods that utilize optical frequency discriminators based on fiber Bragg gratings. In some embodiments, an optical frequency discriminator has a polarization-maintaining fiber Bragg grating (PM-FBG), and an incoming polarized optical signal is reflected from the PM-FBG, which differentiates the two polarization modes in the incoming signal according its frequency relative to the two resonance peaks of the PM-FBG. The optical frequency discriminator then compares (e.g., subtracts) the reflected power in the two polarization modes to provide an output having an amplitude that varies linearly with the frequency of the incoming signal. This output may then be used to extract various information about the frequency of the incoming signal. As an example, the output may be used to recover data that has been frequency modulated onto the incoming signal or to characterize the frequency noise of the incoming signal.

A semiconductor device includes a first insulating film, a first optical waveguide and a second optical waveguide. The first insulating film has a first surface and a second surface opposite to the first surface. The first optical waveguide is formed on the first surface of the first insulating film. The second optical waveguide is formed on the second surface of the first insulating film. The second optical waveguide, in plan view, overlaps with an end portion of the first optical waveguide without overlapping with another end portion of the first optical waveguide.

Exemplary arrangements relate to receivers for receiving information using very weak light pulses. The exemplary arrangements include an input optical signal having a sequence of light pulses, optical elements, and a detector. The optical elements include at least one polarisation modulator, at least one polarisation splitting cube, an element with a different optical path length for different polarisations, and at least one polarization rotating plate. Part of the optical signal follows a shorter optical path length, and part of it follows a longer optical path length. The element with different optical path lengths is placed between two polarisation beam splitter cubes. The beam splitter cubes split and then merge the sequence of pulses reducing the sequence by half and forming an amplified signal readable by the detector. Exemplary arrangements also relate to a method for transmitting information using the exemplary arrangement.

The present disclosure relates to an imaging system which may make use of an electronic controller, a digital micromirror array, an aperture control system and a detector to image a desired scene. The digital micromirror array has a plurality of micromirror elements responsive to control signals generated by the electronic controller for electronically aiming the micromirror elements in a desired direction to image the desired area, and for receiving and reflecting light emanating from the desired area. The aperture control system receives light reflected from the digital micromirror array and passes a predetermined subportion of the received light therethrough. The detector is responsive to the predetermined subportion of light.

High-performance ultra-wideband Phased Array Antennas (PAA) are disclosed, having unique capabilities, enabled through photonic integrated circuits and novel optical architectures. Unique capabilities for PAA systems are enabled by photonic integration and ultra-low-loss waveguides. Novel aspects include optical multiplexing combining wavelength division multiplexing and/or a novel extension to array photodetectors, providing the capability to combine many RF photonic signals with very low loss. Architectures include tunable optical up-conversion and down-conversion systems, moving a chosen frequency band between baseband and a high RF frequency band with high dynamic range. Simultaneous multi-channel RF beamforming is achieved through power combining/splitting of optical signals.

Photo-resonator optical detectors and optical receiver systems incorporating same, In one example, an optically resonant detector includes a housing having an optical window, a photodetector disposed within the housing, and an optical resonator disposed in optical alignment with the photodetector within the housing and positioned between the optical window and the photodetector, the optical resonator being configured to receive an input optical signal via the optical window and to provide an output optical signal to the photodetector.

A communication terminal based on free space optical communication, a communication device, and a communication system are provided. The communication system includes a communication terminal, communication devices, and a master control device. The first communication device includes a light emitting unit configured to transmit an optical signal and a second switching control unit configured to establish a connection with the communication terminal that has received the optical signal. The communication terminal includes a light receiving unit configured to receive the optical signal transmitted by the first communication device and a first switching control unit configured to set the first communication device as a switching destination according to the optical signal. The master control device includes a third switching control unit configured to receive a switch request containing identification information of the communication terminal and transmit a connection instruction to the first switching control unit according to the switching request.

An installation assist apparatus according to an embodiment of the present disclosure includes hardware processor configured to: receive an input of installation positions of first and second optical wireless communication devices performing optical wireless communication and an input of an angle of elevation representing an inclination of an optical axis center line to a horizontal line, the optical axis center line connecting the first and second optical wireless communication devices; determine whether each of the first and second optical wireless communication devices is affected by solar light, the determination being carried out based on the installation positions of the devices, the angle of elevation, an influence angle representing a maximum value of an incident angle of solar light affecting the devices, and solar positions through a whole year; and cause a display device to display a result of the determination.

A semiconductor device includes light-emitting elements, a selection circuit, a control circuit, light-receiving elements, and switch elements. The selection circuit is configured to accept one input signal and output a signal for selecting an element to emit light among the light-emitting elements. The control circuit is configured to control the light-emitting elements, based on the signal outputted from the selection circuit. The light-receiving elements are each configured to receive light of each of the light-emitting elements and generate a signal for driving a switch, based on a light-receiving state. The switch elements are each configured to be driven by application of voltage outputted from each of the light-emitting elements.

The present disclosure relates to an imaging system which may make use of an electronic controller, a digital micromirror array, an aperture control system and a detector to image a desired scene. The digital micromirror array has a plurality of micromirror elements responsive to control signals generated by the electronic controller for electronically aiming the micromirror elements in a desired direction to image the desired area, and for receiving and reflecting light emanating from the desired area. The aperture control system receives light reflected from the digital micromirror array and passes a predetermined subportion of the received light therethrough. The detector is responsive to the predetermined subportion of light.