Abstract: A wireless system may include a central processor and an access point. The central processor may generate an optical signal on an optical fiber. The optical signal may include an optical local oscillator (LO) signal and one or more carriers. The central processor may modulate different combinations of transverse optical modes, orbital angular momentum, polarization, and/or carrier frequency of the optical signal to concurrently convey respective wireless data streams. The orthogonality of the transverse optical modes, orbital angular momentum, polarization, and carrier frequency may allow many wireless data streams to be modulated onto the optical signal and concurrently transmitted and propagated on the optical fiber independent of each other for transmission to one or more external devices.

Abstract: An electronic device may include an optical demultiplexer, optical combiners, optical paths between the demultiplexer and the combiners, modulators on the optical paths, and a symbol generator that generates a set of electrical OFDM symbols. The modulators may generate a set of optical OFDM symbols by mixing optical carriers with the electrical OFDM symbols. The combiners may generate an aggregate optical OFDM symbol from the optical OFDM symbols and may combine the aggregate optical OFDM symbol with an optical local oscillator signal. The aggregate optical OFDM symbol may exhibit a large bandwidth. The combiners may illuminate a photodiode, which produces current on an antenna resonating element that radiates a radio-frequency signal at frequencies greater than 100 GHz.

Abstract: Circuits, methods, and apparatus that can route signals for wireless communications throughout an electronic device in an efficient manner that can save space, reduce noise, improve coexistence, and be readily assembled. An example can route signals through an electronic device using a bus, ring, or daisy-chain topology. Use of this topology can simplify routing, thereby saving space that can be used for additional functionality for the electronic device, a reduction in size of the electronic device, or both. Fiber-optic segments can be used for signal routing to decrease noise.

Abstract: An electronic device may include wireless circuitry that conveys wireless signals and that is clocked using clocking circuitry. The clocking circuitry may include a signal source that generates a clock signal and a loop path coupled between the input and the output of the signal source. A digital frequency discriminator (DFD) may be disposed on the loop path. The DFD may include a digital delay and digital phase shifter coupled between an input converter and a digital mixer. The DFD may receive the clock signal and may generate a control signal indicative of phase noise of the clock signal. The DFD may feed the control signal back into the input of the signal source to mitigate the phase noise. The DFD may minimize phase noise of the signal source while minimizing space and power consumption on the device relative to analog frequency discriminators.

Abstract: An electronic device may include a receiver having a light source that provides an optical signal to an optical splitter. An optical combiner may be coupled to the optical splitter over a set of parallel optical paths. A phased antenna array may have a set of antennas disposed on the optical paths. Each antenna may include an optical modulator disposed on a respective one of the optical paths and an antenna resonating element coupled to the modulator. Incident radio-frequency signals may produce electrical signals on the antenna resonating elements. Optical phase shifters may provide optical phase shifts to the optical signal. The modulators may modulate the optical local oscillator signal using the electrical signals. The optical combiner may generate a combined signal by combining modulated optical signals from the optical paths. A demodulator may recover wireless data from the radio-frequency signals using the combined signal.

Abstract: A communication system may include a wireless base station (BS), a user equipment (UE) device, and a hybrid reconfigurable intelligent surface (HRIS) co-located with the UE device. The HRIS may be used to offload beam management procedures to the BS. Adjustable devices on the HRIS may configure antenna elements of the HRIS to reflect incident signals from the BS and may configure antenna elements of the HRIS to receive the incident signals using a receiver according to a time domain multiplexing scheme, a spatial domain multiplexing scheme, and/or a power domain multiplexing scheme. The UE device may control the HRIS to switch between the schemes and to adjust a proportion of the incident signal that is reflected or received over time. The HRIS may be used in facilitating a beam acquisition and tracking procedure for the UE device and the BS, thereby minimizing resource consumption on the UE device.

Abstract: An electronic device may include an antenna that conveys wireless signals at frequencies greater than 100 GHz. The antenna may include a radiating element coupled to a uni-travelling-carrier photodiode (UTC PD). An optical path may illuminate the UTC PD using a first optical local oscillator (LO) signal and a second optical LO signal. An optical phase shift may be applied to the first optical LO signal. A Mach-Zehnder modulator (MZM) may be interposed on the optical path. During signal transmission, the MZM may modulate wireless data onto the second optical LO signal while control circuitry applies a first bias voltage to the UTC PD. During signal reception, the control circuitry may apply a second bias voltage to the UTC PD that configures the UTC PD to convert received wireless signals into intermediate frequency signals and/or optical signals.

Abstract: An electronic device may include a photonics-based phased antenna array that conveys wireless signals at frequencies greater than 100 GHz. In a transmit mode, the array may transmit signals using the first and second optical signals. In a receive mode, the array may receive signals using the optical signals. In a passive mode, the array may reflect incident wireless signals as reflected signals. Photodiodes in the array may be controlled to exhibit output impedances that are mismatched with respect to input impedances of radiating elements in the array. Different mismatches can be used across the array or as a function of time to impart different phase and/or frequency shifts on the reflected signals. The phase shifts may be used to encode information into the reflected signals and/or to form a signal beam of the reflected signals.

Abstract: 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.

Abstract: A communication system may include an access point (AP), a user equipment (UE), and a communication path between the AP and the UE having a series of reconfigurable intelligent surfaces (RIS's). Each RIS may have a first beam pointing to a previous node and a second beam pointing to a next node in the communication path. Beams of routing RIS's and a beam from an end user RIS towards a last routing RIS may be set during calibration. The UE may perform beam discovery with the end user RIS. The UE and the AP may convey wireless data via reflections off each of the RIS's in the communication path. The beam of the end user RIS may be updated to track the UE device while the other the beams remain fixed. The beams may be calibrated using retroreflection and beam variation for each pair of RIS's up the communication path.

Abstract: 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.

Abstract: 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.

Abstract: A system may include an access point (AP), user equipment (UE), and a reconfigurable intelligent surface (RIS). The RIS may include an array of elements coupled to adjustable devices controlled to cause the array to reflect signals in different directions. The RIS may be controlled in a first mode in which the AP controls the adjustable devices, a second mode in which the UE controls the adjustable devices, and a third mode in which the RIS controls the adjustable devices. The RIS, AP, or UE may determine which mode to place the RIS in based on a downlink signal transmitted by the AP, an uplink signal transmitted by the UE, measurements of the signals performed on the RIS, a first distance or round trip time between the AP and the RIS, and/or a second distance or round trip time between the UE and the RIS.

Abstract: A system may include an access point (AP), user equipment (UE), and a reconfigurable intelligent surface (RIS). The RIS may include an array of elements coupled to adjustable devices controlled to cause the array to reflect signals in different directions. The RIS may be controlled in a first mode in which the AP controls the adjustable devices, a second mode in which the UE controls the adjustable devices, and a third mode in which the RIS controls the adjustable devices. The RIS, AP, or UE may determine which mode to place the RIS in based on a downlink signal transmitted by the AP, an uplink signal transmitted by the UE, measurements of the signals performed on the RIS, a first distance or round trip time between the AP and the RIS, and/or a second distance or round trip time between the UE and the RIS.

Abstract: A system may include an access point (AP), a user equipment (UE) device, and a reconfigurable intelligent surface (RIS). The RIS may have antenna elements and phase shifters programmed using phase settings to form signal beams. The AP may calculate a first portion of the phase settings and may transmit the first portion to the RIS. The RIS may include a first processor that generates a second portion of the phase settings. The RIS may include a second processor coupled to the first processor over a bus. The second processor may generate the phase settings based on the second portion. The second processor may distribute the phase settings to the phase shifters. By distributing calculation of the phase settings between the AP and the RIS, power consumption of the system may be minimized while also minimizing the time required to re-configure the beams of the RIS.

Abstract: A communication system may include an access point (AP), a user equipment (UE), and a communication path between the AP and the UE having a series of reconfigurable intelligent surfaces (RIS's). Each RIS may have a first beam pointing to a previous node and a second beam pointing to a next node in the communication path. Beams of routing RIS's and a beam from an end user RIS towards a last routing RIS may be set during calibration. The UE may perform beam discovery with the end user RIS. The UE and the AP may convey wireless data via reflections off each of the RIS's in the communication path. The beam of the end user RIS may be updated to track the UE device while the other the beams remain fixed. The beams may be calibrated using retroreflection and beam variation for each pair of RIS's up the communication path.

Abstract: An electronic device may include a receiver having a light source that provides an optical signal to an optical splitter. An optical combiner may be coupled to the optical splitter over a set of parallel optical paths. A phased antenna array may have a set of antennas disposed on the optical paths. Each antenna may include an optical modulator disposed on a respective one of the optical paths and an antenna resonating element coupled to the modulator. Incident radio-frequency signals may produce electrical signals on the antenna resonating elements. Optical phase shifters may provide optical phase shifts to the optical signal. The modulators may modulate the optical local oscillator signal using the electrical signals. The optical combiner may generate a combined signal by combining modulated optical signals from the optical paths. A demodulator may recover wireless data from the radio-frequency signals using the combined signal.

Abstract: An electronic device may include a fully-connected photonic phased antenna array having a set of antennas, each with an antenna resonating element coupled to a set of photodiodes. Optical modulators may receive different wireless data streams and may generate modulated signals. Optical paths may provide the modulated signals generated by each modulator to a different photodiode in each antenna. Sets of optical phase shifters may apply different sets of phase shifts for each of the modulated signals. Optical paths may provide the phase shifted signals to the photodiodes in the antennas. The photodiodes may produce currents that are superposed on the antenna resonating elements. Each antenna may be used to concurrently convey all of the wireless data streams. The phase shifts may configure the array to transmit signals that include the wireless data streams within different respective signal beams.

Abstract: An electronic device may include a photonics-based phased antenna array that conveys wireless signals at frequencies greater than 100 GHz. In a transmit mode, the array may transmit signals using the first and second optical signals. In a receive mode, the array may receive signals using the optical signals. In a passive mode, the array may reflect incident wireless signals as reflected signals. Photodiodes in the array may be controlled to exhibit output impedances that are mismatched with respect to input impedances of radiating elements in the array. Different mismatches can be used across the array or as a function of time to impart different phase and/or frequency shifts on the reflected signals. The phase shifts may be used to encode information into the reflected signals and/or to form a signal beam of the reflected signals.

Abstract: An electronic device may include an antenna that conveys wireless signals at frequencies greater than 100 GHz. The antenna may include a radiating element coupled to a uni-travelling-carrier photodiode (UTC PD). An optical path may illuminate the UTC PD using a first optical local oscillator (LO) signal and a second optical LO signal. An optical phase shift may be applied to the first optical LO signal. A Mach-Zehnder modulator (MZM) may be interposed on the optical path. During signal transmission, the MZM may modulate wireless data onto the second optical LO signal while control circuitry applies a first bias voltage to the UTC PD. During signal reception, the control circuitry may apply a second bias voltage to the UTC PD that configures the UTC PD to convert received wireless signals into intermediate frequency signals and/or optical signals.