An optical transmission apparatus includes a wavelength converter that wavelength-converts input signal light using a nonlinear optical medium to output the converted signal light, a memory that holds first information relating to a wavelength conversion characteristic of the wavelength converter, a communication interface that receives second information relating to a second wavelength conversion characteristic of an adjacent optical transmission apparatus, and a control circuit that determines, using the first information and the second information when the second information is received, an excitation light frequency at which a gain deviation of main signal light subjected to a wavelength conversion is minimized to set the determined excitation light frequency in the wavelength converter.

A wavelength conversion device that converts input signal light having a first frequency into output signal light having a second frequency, includes: a control-light generator that outputs first continuous oscillation light and second continuous oscillation light; and a nonlinear optical medium that cross-phase modulates the input signal light with the first continuous oscillation light and the second continuous oscillation light and generates the output signal light, wherein the control-light generator outputs the first continuous oscillation light and the second continuous oscillation light to have polarized waves in directions orthogonal to each other and have a frequency interval equal to a difference between the first frequency and the second frequency and controls, based on intensity of the output signal light, timings of modulation of phases of the first continuous oscillation light and the second continuous oscillation light to be aligned with each other.

A neural imaging system may include an imaging array, an image data processor operably coupled to the imaging array to process image data received from the imaging array, and a beam angle separator disposed between the imaging array and an object being imaged. The beam angle separator may be configured to separate an object beam reflected from the object being imaged into a plurality of reference beams each having different angular separation with respect to the object beam. The image data processor may be configured to generate image data of the object for each one of the reference beams to correspond to a respective different depth within the object.

Optical receivers configured to demodulate phase modulated optical signals. In one example, an optical signal receiver includes an optical resonator configured to receive an arriving optical signal and to emit an output optical signal in response to receiving the arriving optical signal, the optical resonator being further configured to transform phase transitions corresponding to phase modulation of the arriving optical into intensity modulation of the output optical signal, an opto-electrical converter configured to convert the output optical signal into an electrical signal, a pulse detector configured to detect pulses in the electrical energy indicative of the phase transitions in the arriving optical signal, and a memory configured to record timing information associated with the pulses detected by the pulse detector.

Optical receivers configured to demodulate phase modulated optical signals. In one example, an optical signal receiver includes an optical resonator configured to receive an arriving optical signal and to emit an output optical signal in response to receiving the arriving optical signal, the optical resonator being further configured to transform phase transitions corresponding to phase modulation of the arriving optical into intensity modulation of the output optical signal, an opto-electrical converter configured to convert the output optical signal into an electrical signal, a pulse detector configured to detect pulses in the electrical energy indicative of the phase transitions in the arriving optical signal, and a memory configured to record timing information associated with the pulses detected by the pulse detector.

A photonic frequency converter includes an electro-optical intensity modulator having an optical input, one optical output and at least one RF input for receiving two modulation radiofrequency signals at different frequencies; a set of optical sources that are configured to generate optical signals at at least two different wavelengths, the signals being modulated by respective local-oscillator signals at least two of which have different frequencies; and an optical multiplexer arranged to multiplex the optical signals and to inject them into the optical input of the modulator. A method for converting frequency by means of such a converter is also provided.

An apparatus embedded with one or more terahertz transceivers is described. The one or more terahertz transceivers based on at least one optical source is provided to facilitate wireless communication in the apparatus, where the apparatus is embedded with one or more planar antennas. The transceiver operates in terahertz and may be coupled to two different antennas, one for transmission and the other for reception.

Devices, systems and methods for encoding information using optical components are described. An example photonic filtered sampler includes a spectral shaper configured to receive an optical pulse train, a dispersive element positioned to receive an output of the spectral shaper and to expand spectral contents thereof in time, and a modulator configured to receive an output of the dispersive element and a radio frequency (RF) signal, and to produce a modulated output optical signal in accordance with the RF signal. In this configuration, one or more characteristics of the modulated output optical signal is determined based on a spectral shape provided by the spectral shaper and dispersive properties of the dispersive element.

To provide an optical 90-degree hybrid formed of a silicon waveguide capable of suppressing an optical loss and a phase error, and facilitating electronic packaging and optical packaging. In the optical 90-degree hybrid circuit including two optical branching units facing each other and two optical coupling units facing away from each other, four arm waveguides are arranged including bent waveguides each of which guides an output light of the optical branching unit to the optical coupling unit, and is formed in a curved shape.

A fast optical (with or without a photonic crystal) switch is fabricated/constructed, utilizing a phase transition material/Mott insulator, activated by either an electrical pulse (a voltage pulse or a current pulse) and/or a light pulse and/or pulses in terahertz (THz) frequency of a suitable field strength and/or hot electrons. The applications of such a fast optical switch for an on-demand optical add-drop subsystem, integrating with (a) a light slowing/light stopping component (based on metamaterials and/or nanoplasmonic structures) and (b) with or without a wavelength converter are also described.