A transceiver comprises a transmitter including a light source, a modulator coupled to the light source, a driver that drives the modulator according to a set of driving conditions to cause the modulator to output optical signals based on light from the light source, and an output that passes first portions of the optical signals output by the modulator. The transceiver further comprises a first detector that detects second portions of the optical signals output from the modulator, and a receiver including a second detector that detects optical signals from an external transmitter.

Apparatus and method for digital signal constellation transformation are provided herein. In certain configurations, an integrated circuit includes an analog front-end that converts an analog signal vector representing an optical signal into a digital signal vector, and a digital signal processing circuit that processes the digital signal vector to recover data from the optical signal. The digital signal processing circuit generates signal data representing a signal constellation of the digital signal vector. The digital signal processing circuit includes an adaptive gain equalizer that compensates the signal data for distortion of the signal constellation arising from biasing errors of optical modulators used to transmit the optical signal.

In order to stabilize the characteristics of reception of an optical signal received via a transfer path, this optical receiver is provided with: a local beam output means 1; a light receiving means 2; a photoelectric conversion means 3; a measuring means 4; a control means 5; and a comparing means 6, the comparing means 6, when the control means 5 sweeping the wavelength of the local beam in a predetermined wavelength range with respect to the central wavelength of the optical signal, generating difference data between a spectrum based on a result of the measuring, by the measuring means 4, of the electric signal in accordance with a change in the wavelength of the local beam and a preset reference spectrum.

An optical network component, system, and method are herein described. The system and method include introducing an AM tone and data to an optical modulator generating a modulated optical signal, measuring an amplitude response of the AM tone within the modulated optical signal, calculating a frequency response based on the amplitude response, and calibrating the optical modulator with the frequency response.

An optical-communication module includes a transceiver to communicate with another optical-communication module (another module); and a control circuit to transmit a first signal to the another module at activation of the own module, execute a first control where a second signal transmitted to the first signal is received from the another module, and execute a second control after the first control, wherein one of the first and second control is a control to adjust an intensity of a signal from the transceiver to the another module based on a feedback signal from the another module to a signal from the transceiver, and wherein the other one of the first and second control is a control causing the another module to adjust a signal intensity from the another module to the transceiver by transmitting a feedback signal to the another module to a signal from the another module.

Apparatus and method for digital signal constellation transformation are provided herein. In certain configurations, an integrated circuit includes an analog front-end that converts an analog signal vector representing an optical signal into a digital signal vector, and a digital signal processing circuit that processes the digital signal vector to recover data from the optical signal. The digital signal processing circuit generates signal data representing a signal constellation of the digital signal vector. The digital signal processing circuit includes an adaptive gain equalizer that compensates the signal data for distortion of the signal constellation arising from biasing errors of optical modulators used to transmit the optical signal.

An example device may include an optical modulator configured to generate an optical beam encoding network data, an optical power amplifier configured to adjust a transmitted power of the optical beam, and a transmit beam angle mechanism configured to adjust a beam direction of the optical beam and to transmit the optical beam to a remote receiver over a free-space optical link. Example devices may include a controller configured to receive backchannel data from the remote receiver and modify a characteristic of the optical beam based on the backchannel data. Various other devices, systems, and methods are also disclosed.

Methods and apparatus for providing spectrally beam-combined fiber-based transmitters and/or receivers for laser communications, LiDAR, and similar devices. A transmitter can include a launch array configured to spatially position each output beam of pulsed lasers, a transform optical component to correct deflection of the output beams of the pulsed lasers from the launch array, and a dispersive optical element to combine beams from the transform optical element and generate a spectrally combined beam. A receiver can include spectral comb filters to spectrally discriminate multi-wavelength detected signals from background illumination.

Materials containing picocrystalline quantum dots that form artificial atoms are disclosed. The picocrystalline quantum dots (in the form of born icosahedra with a nearly-symmetrical nuclear configuration) can replace corner silicon atoms in a structure that demonstrates both short range and long-range order as determined by x-ray diffraction of actual samples. A novel class of boron-rich compositions that self-assemble from boron, silicon, hydrogen and, optionally, oxygen is also disclosed. The preferred stoichiometric range for the compositions is (B.sub.12H.sub.w).sub.xSi.sub.yO.sub.z with 3≤w≤5, 2≤x≤4, 2≤y≤5 and 0≤z≤3. By varying oxygen content and the presence or absence of a significant impurity such as gold, unique electrical devices can be constructed that improve upon and are compatible with current semiconductor technology.

Optical transmitter includes: signal processing circuit, optical modulator, optical filter, and delay circuit. The signal processing circuit generates N drive signals for generating a modulated optical signal. Symbol rate of the modulated optical signal is fs and each symbol of the modulated optical signal transmits N bits. The optical modulator includes Mach-Zehnder interferometer and N phase-shift segments each of which shifts a phase of light propagating through an optical path of the Mach-Zehnder interferometer according to the N drive signals. The optical filter removes, from output light of the optical modulator, a frequency component in a range of ±fs/2 with respect to a center frequency of the modulated optical signal, and extracts at least a part of other frequency components. The delay circuit controls timings of the N drive signals so as to reduce optical power of the frequency component extracted by the optical filter.