An optoelectronic transmitter (10) includes an electro-optic modulator (12), digital driving circuitry (14), and feedback circuitry (30). The electro-optic modulator is configured to modulate an optical signal in response to an electrical drive signal. The digital driving circuitry is coupled to the electro-optical modulator and is configured to generate the electrical drive signal. The feedback circuitry is configured to measure a quantity indicative of a power level of the modulated optical signal produced by the electro-optic modulator, and to adapt a supply voltage to the digital driving circuitry in response to the measured quantity.

Provided is a signal processor provided in a transceiver for transmitting and receiving a radio signal, and including a branch unit, a detection unit, a determination unit, and a power source controller. The branch unit branches a transmission signal and acquires a branch signal. The detection unit detects the branch signal and acquires a voltage value of the branch signal. The determination unit compares the voltage value of the branch signal with a threshold voltage previously stored in a storage unit and determines whether the voltage value of the branch signal is equal to or greater than the threshold voltage. The power source controller controls turning on and off of a power source for a reception signal amplifier of the transceiver according to a determination result determined by the determination unit.

A photonic control system is disclosed for optical control of superconducting RF structures. The photonic control system includes an optical light source transmitter including a laser and an RF driver supplying an optical signal. An optical fiber assembly is optically coupled to the optical light source transmitter. A photodetector is optically coupled to the optical light source transmitter via the optical fiber. The photodetector converts the optical signal to an RF signal. A photonically controlled superconducting RF structure such as a qubit or a readout resonator receives the RF signal from the photodetector.

Provided is a high-speed optical transmission-reception apparatus including a digital-signal processing circuit and optical modulation and optical reception modules, in which a flexible printed circuit is used as a high-frequency interface for the optical modulation and optical reception modules, a mechanism for connecting the high-frequency line pattern to the flexible printed circuit is provided on a package substrate of the digital-signal processing circuit, and the package substrate and the optical modulation and optical reception modules are connected by the flexible printed circuit.

Provided is a distributed antenna system (DAS) for multi-frequency band and multi-carrier equipped with an open radio access network (O-RAN) remote unit (RU) according to an O-RAN technology standard for building a next-generation radio infrastructure. To this end, the DAS for multi-carrier and multi-frequency band based on an O-RAN standard includes an O-RAN RU connected to a fronthaul network according to an O-RAN split option specification of base station transceiver systems (BTSs), and including a plurality of O-RAN RUs to accommodate a plurality of carriers and a plurality of frequency bands; and a channel combiner to which outputs of the plurality of O-RAN RUs are combined.

An RF imaging receiver using photonic spatial beam processing is provided with an optical beam steerer that directs the modulated optical signals to steer the composite optical signal and move the location of the spot on the optical detector array. The optical beam steerer may be implemented with one or more phase-dependent steering units in which each unit includes a waveplate and polarization grating to steer the modulated optical signals. The optical beam steerer may be configured to act on the individual modulated optical signals to induce individual phase delays that produce a phase delay with a linear term, and possibly spherical or aspherical terms, to steer the composite optical signal in which case the optical beam steerer may be implemented, for example, with an optical phase modulator and optical antenna in each optical channel which together form an OPA, a Risley prism or a liquid crystal or MEMs spatial light modulator.

A microcontroller includes a setting unit, an encoder, a modulation circuit, and a digital-to-analog converter. The setting unit outputs a control signal. The encoder outputs a digital signal that is encoded. The modulation circuit loads at least one carrier signal on the digital signal at the logic high level and/or the logic low level according to the control signal to generate a modulated digital signal. The digital-to-analog converter converts the modulated digital signal into an analog signal, and outputs the analog signal for transmission.

An RF imaging receiver using photonic spatial beam processing is provided with an optical beam steerer that directs the modulated optical signals to steer the composite optical signal and move the location of the spot on the optical detector array. The optical beam steerer may be implemented with one or more phase-dependent steering units in which each unit includes a waveplate and polarization grating to steer the modulated optical signals. The optical beam steerer may be configured to act on the individual modulated optical signals to induce individual phase delays that produce a phase delay with a linear term, and possibly spherical or aspherical terms, to steer the composite optical signal in which case the optical beam steerer may be implemented, for example, with an optical phase modulator and optical antenna in each optical channel which together form an OPA, a Risley prism or a liquid crystal or MEMs spatial light modulator.

A radio communication system for duplex communication comprising an optical carrier generator for generating optical carrier signals, a local oscillator (LO) for generating an electrical signal in a radio communication band, an information signal source, electro-optic modulators driven directly at an input electrical port by said information signal and said LO signal to modulate a portion of said optical carrier signal to form a modulated portion being an optical band information signal for transmission over an optical link; and a photodetector remote from said electro-optic modulators for receiving said transmitted optical band information signal from said optical link, and directly generating an electrical signal that is up-converted for radio transmission, or down-converted to a baseband frequency.

Joint estimation of the framer index and the frequency offset in an optical communication system are described among various other features. A transmitter can transmit data frames using pilot and framer symbols. A receiver can estimate the framer index and frequency offset using the pilot and framer symbols, and identify the beginning of a header portion of a data frame. By identifying the beginning of the header portion of a data frame, the receiver can synchronize, with less error, the data transmitted by the transmitter and the data it received. To further improve the framer index estimation, a lock indicator signal can be generated to signal to other receiver components that the estimated framer indices are reliable. The receiver can determine frequency offset and additional framer index estimations with increased reliability when performed after the lock indicator signal is generated.