A system and method for analog estimation of a spectral correlation function (SCF) provides a photonic carrier to generate a signal comb and offset comb, each comprising N comb tones separated by respective repetition rates ΔF and ΔF+δF. The signal and offset combs are amplitude-modulated according to an inbound RF signal of interest and filtered via periodic optical filters to produce a sequence of N Fourier components of the signal comb and N Fourier components of the offset comb, each filtered signal comb component overlapping with a filtered offset comb component. In-phase/quadrature (I/Q) components of the products of each component of the complex conjugate of the filtered offset comb and the overlapping counterpart of the filtered signal comb are generated in an optical receiver and digitized into slices of the SCF at a fixed time instance and center frequency, correlated at various cyclic separations α.

A plurality of digital processors may be used to adjust phases in a plurality of phase modulators. The plurality of digital processors may receive a periodic pulse, or heartbeat signal, from a synchronization controller in order to control the digital processors. The synchronization controller may output an additional signal used to determine and to control the phase of the signals output from the plurality of phase modulators.

An optical beamforming device includes an RF front-end transmitting or receiving RF signals and an optical beamformer forming or compensating for a time delay for each of the plurality of channels based on the RF signals. The optical beamformer includes E/O converters converting the RF signals into optical signals, respectively, a linear modulator generating an optical modulation signal based on an RF input signal, a TTD array outputting an optical combined signal obtained by compensating for a time delay degree of the input optical signals or outputting output optical signals, in each of which a time delay is formed for each channel, by distributing the optical modulation signal, a photo detector generating an RF output signal to an RF back-end based on the optical combined signal, and O/E converters converting the output optical signals into RF signals, respectively.

A sensing system. In some embodiments, the system includes a first imaging radio frequency receiver, a second imaging radio frequency receiver, a first optical beam combiner, a first imaging optical receiver, a second optical beam combiner, and an optical detector array. The first optical beam combiner may be configured to combine optical signals of the imaging radio frequency receivers. The second optical beam combiner may be configured to combine the optical signals of the imaging radio frequency receivers, and the optical signal of the first imaging optical receiver.

A first device may generate optical signals of different polarizations. Photodiodes may use the optical signals to transmit wireless signals at different polarizations and at a frequency greater than 100 GHz using the optical signals. A second device may receive the wireless signals and may convert the wireless signals into optical signals. A Stokes vector receiver on the second device may generate Stokes vectors based on the optical signals. Control circuitry on the second device may use the Stokes vectors generated for a series of training data in the wireless signals to generate a rotation matrix that characterizes polarization rotation between the first and second devices. The control circuitry may multiply wireless data in subsequently received wireless signals by the rotation matrix to mitigate the polarization rotation and other transmission impairments while using minimal resources.

An apparatus for generating a time-delayed product of two independent signals includes a fixed-wavelength laser. A first optical modulator is optically coupled to the fixed-wavelength laser and configured to modulate a fixed wavelength optical carrier with a first input signal of a set of input signals. The apparatus also includes a tunable laser. A second optical modulator is optically coupled to the tunable laser and configured to modulate a tunable optical carrier with a second input signal of the set of input signals. The apparatus also includes a dispersive element coupled to the second optical modulator, a first optical detector coupled to the dispersive element, a third optical modulator optically coupled to the first optical detector and the first optical modulator, an optical 90-degree hybrid element optically coupled to the third optical modulator, and a plurality of optical detectors optically coupled to the optical 90-degree hybrid element.

Methods and apparatuses for downconverting high frequency subbands to a lower frequency band and recovering signals-of interest. The system includes a controller, a signal generator, an optical source, a dual-drive mach zehnder modulator (DDMZM), a photodetector, and a dechipping/image (DI) rejector. The controller outputs chipping frequencies to the signal generator which generates local oscillator (LO) tones shifted by the respective chipping frequencies. The optical source outputs an optical signal to the DDMZM which has first and second arms and modulators. The first modulator receives a signal from a source and modulates it onto the optical signal propagating through the first arm to form a first modulated optical signal. The second modulator receives the shifted local oscillator tones and modulates them onto the optical signal propagating through the second arm to form a second modulated optical signal. The DDMZM outputs a signal which is a combination of the first and second modulated optical signals to the photodetector which generates a corresponding electrical signal. The dechipping/image (DI) rejector receives the electrical signal and one of the chipping frequencies and outputs a signal that maximizes signals in one high frequency subband while suppressing signals in other high frequency subbands.

A signal processor apparatus includes: first and second photonic comb generators generating respective first and second combs with respective different first and second tone spacing; modulator modulating the first comb with an analog input signal; combiner combining the modulated first comb with the second comb and directing the combination results to first and second arms; spectral filter unit for each arm dividing each arm into a plurality of sub-bands; plurality of photodetectors, one for each sub-band of each arm, each photodetector outputting an electrical signal carrying information on the respective sub-band of the input signal; phase-shifter adjusting a relative phase of the first and second combs with respect to each other prior to the combiner; sensor system producing an output related to a phase difference between the first and second combs at the combiner; and controller controlling the phase-shifter based on the output of the sensor system.

An electronic device may include wireless circuitry clocked using an electro-optical phase-locked loop (OPLL) having primary and secondary lasers. A frequency-locked loop (FLL) path and a phase-locked loop (PLL) path may couple an output of the secondary laser to its input. A photodiode may generate a photodiode signal based on the laser output. A digital-to-time converter (DTC) may generate a reference signal. The FLL path may coarsely tune the secondary laser based on the photodiode signal until the secondary laser is frequency locked. Then, the PLL path may finely tune the secondary laser based on the reference signal and the photodiode signal until the phase of the secondary laser is locked to the primary laser. The photodiode signal may be subsampled on the PLL path. This may allow the OPLL to generate optical local oscillator signals with minimal jitter and phase noise.

A communication system may an optical signal generator and a signal path. The generator may generate one or more optical local oscillator (LO) signals and an optical frequency comb. Optical paths and an optical demultiplexer may distribute the optical LO signal(s) and the frequency comb to photodiodes in one or more access points. The photodiodes may be coupled to antenna radiating elements. The optical paths may illuminate each photodiode using a signal pair that includes one of the optical LO signals and one of the carriers from the frequency comb. The photodiodes may convey wireless signals using the antenna radiating elements at frequencies given by the differences in frequency between the signals in the signal pairs. The radiating elements may concurrently convey the wireless signals with different external devices at different frequencies, with different devices at the same frequency, and/or with the same device at the same frequency.