A pluggable optical connector is configured to be insertable into and removable from an optical communication apparatus, and to be capable of communicating a modulation signal and a data signal with the optical communication apparatus. A wavelength-tunable light source is configured to output an output light and a local oscillation light. An optical transmission unit is configured to output an optical signal generated by modulating the output light in response to the modulation signal. An optical reception unit is configured to demodulate an optical signal received by using the local oscillation light to the data signal. Pluggable optical receptors are configured in such a manner that an optical fiber is insertable into and removable from the pluggable optical receptors, and configured to be capable of outputting the optical signal to the optical fiber and transferring the optical signal received thorough the optical fiber to the optical reception unit.

A pluggable optical connector is configured to be insertable into and removable from an optical communication apparatus, and to be capable of communicating a modulation signal and a data signal with the optical communication apparatus. A wavelength-tunable light source is configured to output an output light and a local oscillation light. An optical transmission unit is configured to output an optical signal generated by modulating the output light in response to the modulation signal. An optical reception unit is configured to demodulate an optical signal received by using the local oscillation light to the data signal. Pluggable optical receptors are configured in such a manner that an optical fiber is insertable into and removable from the pluggable optical receptors, and configured to be capable of outputting the optical signal to the optical fiber and transferring the optical signal received thorough the optical fiber to the optical reception unit.

A Fourier transform is performed on a first waveform function in a frequency domain, and a second waveform function in a time domain including a temporal intensity waveform function and a temporal phase waveform function is generated. A replacement of the temporal intensity waveform function based on a desired waveform is performed for the second waveform function. The second waveform function is modified so as to bring a spectrogram of the second waveform function close to a target spectrogram generated in advance in accordance with a desired wavelength band. An inverse Fourier transform is performed on the modified second waveform function, and a third waveform function in the frequency domain is generated. Data is generated on the basis of an intensity spectrum function or a phase spectrum function of the third waveform function.

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.

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.

A wavelength converter includes a first phase modulator configured to perform phase modulation on pump light in accordance with a first phase modulation signal, a second phase modulator configured to perform phase modulation on signal light in accordance with a second phase modulation signal, a wavelength converter configured to multiplex the signal light having undergone the phase modulation with the pump light having undergone the phase modulation, the wavelength converter configured to perform wavelength conversion on the signal light in accordance with the pump light, a detector configured to detect a modulation component from the signal light having undergone the phase modulation and the pump light having undergone the phase modulation, and a generator configured to generate the first phase modulation signal and the second phase modulation signal so as to minimize the detected modulation component.

Devices, systems and methods for encoding information using optical components are described. Information associated with a first optical signal (e.g., an optical pump) is encoded onto the phase of a second optical signal (e.g., an optical probe) using cross phase modulation (XPM) in a non-linear optical medium. The optical signals are multiplexed together into the nonlinear optical medium. The probe experiences a modified index of refraction as it propagates through the medium and thus accumulates a phase change proportional to the intensity of the pump. The disclosed devices can be incorporated into larger components and systems for various applications such as scientific diagnostics, radar, remote sensing, wireless communications, and quantum computing that can benefit from encoding and generation of low noise, high resolution signals. Examples of the encoded information includes intrinsic noise from the optical source, or others signals of interest, such as electrical, optical, X-ray, or high-energy particle signals.

A radiation source for emitting terahertz radiation (6) is specified, comprising at least two laser light sources emitting laser radiation (11, 12) of different frequencies, and a photomixer (5) comprising a photoconductive semiconductor material (51) and an antenna structure (52), the photomixer (5) being configured to emit the laser radiation (11, 12) of the laser light sources (1, 2) and emitting terahertz radiation (6) with at least one beat frequency of the laser light sources, and wherein the at least two laser light sources are surface-emitting semiconductor lasers (1, 2) which are arranged in a one-dimensional or two-dimensional array on a common carrier (10).

A reception apparatus includes a dispersion compensation unit configured to acquire an electrical signal resulting from conversion of an optical signal and perform, on the electrical signal, dispersion compensation with a predetermined compensation amount, a clip rate measurement unit configured to measure a clip rate for the electrical signal subjected to the dispersion compensation, and a control unit configured to detect the compensation amount that minimizes the clip rate.

A digital coherent receiver includes: an adaptive equalizer configured to execute, using a first tap coefficient, adaptive equalization processing on a digital signal that corresponds to a signal; a first coefficient updating unit configured to update the first tap coefficient based on the digital signal on which the adaptive equalization processing has not been executed, the digital signal on which the adaptive equalization processing has been executed, and a first step size; a second coefficient updating unit configured to update a second tap coefficient based on the digital signal on which the adaptive equalization processing has not been executed, the digital signal on which the adaptive equalization processing has been executed, and a second step size; and a control unit configured to detect a fluctuation speed of a state of polarization of the digital signal based on the second tap coefficient, and change the first tap coefficient to the updated second tap coefficient if it is determined that the fluctuation speed is higher than or equal to a speed threshold.