Electronic device with electro-optical phase-locked loop

Abstract

The present disclosure relates to electronic devices with electro-optical phase-locked loops. An electronic device can include a wireless circuit that is clocked using an electro-optical phase-locked loop (OPLL) with a primary laser and a secondary laser. A frequency-locked loop (FLL) path and a phase-locked loop (PLL) path can couple an output of the secondary laser to an input of the secondary laser. A photodiode can generate a photodiode signal based on a laser output. A digital time converter (DTC) can generate a reference signal. The FLL path can coarsely tune the secondary laser based on the photodiode signal until the secondary laser is frequency-locked. Then, the PLL path can finely tune the secondary laser based on the reference signal and the photodiode signal until a phase of the secondary laser is locked to the primary laser. The photodiode signal can be down-sampled on the PLL path. This can allow the OPLL to generate an optical local oscillator signal with minimal jitter and phase noise.

Description

[0001] This patent application claims priority to U.S. Patent Application No. 17 / 830,087, filed June 1, 2022, and U.S. Provisional Patent Application No. 63 / 246,747, filed September 21, 2021, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This disclosure relates in general to electronic devices, and more specifically to electronic devices having wireless circuitry. Background Technology

[0003] Electronic devices may have wireless capabilities. Wireless-capable electronic devices have wireless circuitry including one or more antennas. The wireless circuitry is used to perform communication using radio frequency signals transmitted by the antennas.

[0004] As software applications on electronic devices become increasingly data-intensive over time, the need for electronic devices that can support wireless communication at higher data rates has increased. However, the maximum data rate supported by electronic devices is limited by the frequency of the radio frequency signal. As the communication frequency increases, it can become difficult to provide low jitter and low phase noise clocks to the wireless circuitry. Summary of the Invention

[0005] An electronic device may include a wireless circuit for transmitting wireless signals at frequencies greater than 100 GHz. The wireless circuitry or other circuitry in the device may use an electro-optical phase-locked loop (OPLL) for timing. The OPLL may include a primary laser that emits a first optical local oscillator (LO) signal at a fixed first frequency; and a secondary laser that emits a second optical LO signal at an adjustable second frequency. The wireless circuitry may, for example, use the first and second optical LO signals to transmit these wireless signals.

[0006] Frequency-locked loop (FLL) and phase-locked loop (PLL) paths can couple the output of the secondary laser to its input. A photodiode can be inserted into both the FLL and PLL paths. The photodiode can generate a photodiode signal based on a first optical LO signal and a second optical LO signal. The OPLL may include a reference oscillator that generates a reference oscillator signal. The OPLL may include a digital-time converter (DTC) that generates a DTC reference signal based on the oscillator signal.

[0007] The FLL path can coarsely tune the secondary laser based on a reference oscillator signal and a photodiode signal. For example, the FLL path may include a counter that estimates the frequency offset between a first optical LO signal and a second optical LO signal. The counter can coarsely tune the secondary laser based on the estimated frequency offset (e.g., until the frequency of the second optical LO signal stabilizes and locks to a predetermined value). Once the frequency of the second optical LO signal is locked, the PLL path can finely tune the secondary laser based on a DTC reference signal and a photodiode signal. For example, the PLL path may include a downsampling mixer that downsamples the photodiode signal to produce a downsampled photodiode signal. The downsampling mixer can finely tune the secondary laser based on the phase difference between the DTC reference signal and the downsampled photodiode signal (e.g., until the phase of the second optical LO signal stabilizes and locks relative to the first optical LO signal). In this way, the first and second optical LO signals can be used to lock the clock portion of device 10 with minimal jitter and phase noise.

[0008] One aspect of this disclosure provides an electro-optical phase-locked loop (EOL). The EOL may include: a first light source configured to emit light at a first frequency. The EOL may include: a second light source configured to emit light at a second frequency offset from the first frequency by an offset frequency of at least 50 GHz. The EOL may include: a feedback path communicatively coupled an output of the second light source to an input of the second light source. The EOL may include: a digital time converter (DTC) configured to generate a reference signal. The EOL may include: a phase comparator inserted along the feedback path, wherein the phase comparator is configured to adjust the second light source at least partially based on the reference signal.

[0009] One aspect of this disclosure provides a method for operating an electro-optical phase-locked loop. The method may include: emitting a first optical local oscillator (LO) signal at a first frequency using a first laser. The method may also include: emitting a second optical LO signal at a second frequency using a second laser, the second frequency being offset from the first frequency by a frequency greater than 50 GHz. The method may further include: coarsely tuning the second optical LO signal emitted by the second laser using a frequency-locked loop (FLL) path communicatively coupled between the output and input of the second laser until the second frequency is locked. The method may also include: once the second frequency is locked, finely tuning the second optical LO signal emitted by the second laser using a phase-locked loop (PLL) path communicatively coupled between the output and input of the second laser until the second optical LO signal is phase-locked with the first optical LO signal.

[0010] One aspect of this disclosure provides an electronic device. The electronic device may include: an antenna radiating element. The electronic device may include: a photodiode coupled to the antenna radiating element and configured to transmit wireless signals at frequencies greater than 100 GHz using the antenna radiating element, a first optical local oscillator (LO) signal, and a second optical LO signal. The electronic device may include: optical components configured to generate the first optical LO signal and the second optical LO signal. These optical components may include a first laser configured to emit the first optical LO signal. These optical components may include a second laser configured to emit the second optical LO signal. These optical components may include a photodiode configured to generate a photodiode signal based on the first optical LO signal and the second optical LO signal. These optical components may include a downsampling mixer configured to generate a downsampled photodiode signal based on the photodiode signal and configured to tune the second laser at least partially based on the phase of the downsampled photodiode signal. Attached Figure Description

[0011] Figure 1 This is a block diagram of an exemplary electronic device having a wireless circuit with at least one antenna according to some embodiments, the at least one antenna transmitting wireless signals at frequencies greater than about 100 GHz.

[0012] Figure 2 A top view of an exemplary antenna for transmitting wireless signals at frequencies greater than approximately 100 GHz based on an optical local oscillator (LO) signal, according to some implementation schemes.

[0013] Figure 3 For illustration of some implementation schemes Figure 2A top view showing how an exemplary antenna of the type shown can convert received wireless signals at frequencies greater than approximately 100 GHz into intermediate frequency signals based on optical LO signals.

[0014] Figure 4 For illustration of some implementation schemes Figure 2 and Figure 3 A top view showing how multiple antennas of the type shown can be stacked to cover multiple polarizations.

[0015] Figure 5 To show how it can be Figure 4 A top view showing a stacked antenna of the type shown integrated into a phased antenna array for transmitting wireless signals at frequencies greater than approximately 100 GHz within the corresponding signal beam.

[0016] Figure 6 The circuit diagram is provided for an exemplary wireless circuit with an antenna according to some embodiments, which transmits and receives wireless signals at frequencies greater than about 100 GHz for conversion to intermediate frequency and then to the optical domain.

[0017] Figure 7 A circuit diagram of an exemplary phased antenna array for transmitting wireless signals at frequencies greater than approximately 100 GHz within a corresponding signal beam, according to some implementation schemes.

[0018] Figure 8 The circuit diagram is an exemplary electro-optical phase-locked loop that can generate low-jitter and low-phase-noise optical local oscillator signals using a primary light source and a secondary light source, according to some implementation schemes.

[0019] Figure 9 This is a timing diagram illustrating how an exemplary digital time converter (DTC) according to some implementations can generate a programmable DTC reference signal for an electro-optical phase-locked loop.

[0020] Figure 10 This is a flowchart illustrating exemplary operations involved in generating low-jitter and low-phase-noise optical local oscillator signals using an electro-optical phase-locked loop, according to some implementation schemes. Detailed Implementation

[0021] Figure 1The electronic device 10 (sometimes referred to herein as electro-optical device 10) may be: a computing device, such as a laptop computer, desktop computer, computer monitor containing an embedded computer, tablet computer, cellular phone, media player, or other handheld or portable electronic device; a smaller device, such as a wristwatch, a hanging device, a headset or handset, a device embedded in glasses, goggles; or other equipment worn on a user's head; or other wearable or micro-devices, televisions, computer monitors without an embedded computer, gaming devices, navigation devices, embedded systems (such as systems in which electronic equipment with a display is installed in a kiosk or vehicle), voice-controlled speakers connected to the wireless Internet, home entertainment devices, remote control devices, game controllers, peripheral user input devices, wireless base stations or access points, equipment that enables the functions of two or more of these devices; or other electronic equipment.

[0022] like Figure 1 As shown in the functional block diagram, device 10 may include components located on or within an electronic device housing, such as housing 12. Housing 12 (sometimes referred to as a shell) may be formed of plastic, glass, ceramic, fiber composite material, metal (e.g., stainless steel, aluminum, metal alloys, etc.), other suitable materials, or combinations of these materials. In some cases, housing 12 may be partially or entirely formed of dielectric or other low-conductivity materials (e.g., glass, ceramic, plastic, sapphire, etc.). In other cases, housing 12 or at least some of the structures constituting housing 12 may be formed of metallic elements.

[0023] Device 10 may include control circuitry 14. Control circuitry 14 may include storage devices, such as storage circuitry 16. Storage circuitry 16 may include hard disk drive storage devices, non-volatile memory (e.g., flash memory configured to form a solid-state drive or other electrically programmable read-only memory), volatile memory (e.g., static random access memory or dynamic random access memory), etc. Storage circuitry 16 may include storage devices and / or removable storage media integrated within device 10.

[0024] Control circuitry 14 may include processing circuitry, such as processing circuitry 18. Processing circuitry 18 may be used to control the operation of device 10. Processing circuitry 18 may include one or more processors, microprocessors, microcontrollers, digital signal processors, host processors, baseband processor integrated circuits, application-specific integrated circuits, central processing units (CPUs), graphics processing units (GPUs), etc. Control circuitry 14 may be configured to perform operations in device 10 using hardware (e.g., dedicated hardware or circuitry), firmware, and / or software. Software code for performing operations in device 10 may be stored on storage circuitry 16 (e.g., storage circuitry 16 may include a non-transitory (tangible) computer-readable storage medium storing software code). This software code may sometimes be referred to as program instructions, software, data, commands, or code. The software code stored on storage circuitry 16 may be executed by processing circuitry 18.

[0025] Control circuitry 14 can be used to run software on device 10, such as satellite navigation applications, internet browsing applications, Voice over Internet Protocol (VoIP) telephone calling applications, email applications, media playback applications, operating system functions, etc. To support interaction with external equipment, control circuitry 14 can be used to implement communication protocols. Communication protocols that can be implemented using control circuitry 14 include Internet Protocol, Wireless Local Area Network (WLAN) protocols (e.g., IEEE 802.11 protocol—sometimes referred to as Wi-Fi). ® ), such as Bluetooth ® Protocols used for other short-range wireless communication links, such as protocols or other Wireless Personal Area Network (WPAN) protocols, IEEE 802.11ad protocols (e.g., Ultra Wideband protocols), cellular phone protocols (e.g., 3G protocols, 4G (LTE) protocols, 3GPP 5th Generation (5G) New Radio (NR) protocols, 6th Generation (6G) protocols, sub-THz protocols, THz protocols, etc.), antenna diversity protocols, satellite navigation system protocols (e.g., Global Positioning System (GPS) protocols, Global Navigation Satellite System (GLONASS) protocols, etc.), antenna-based spatial ranging protocols, optical communication protocols, or any other desired communication protocols. Each communication protocol may be associated with a corresponding Radio Access Technology (RAT), which specifies the physical connection method used to implement the protocol.

[0026] Device 10 may include input-output circuitry 20. Input-output circuitry 20 may include input-output devices 22. Input-output devices 22 may be used to allow data to be supplied to device 10 and to allow data to be supplied from device 10 to external devices. Input-output devices 22 may include user interface devices, data port devices, and other input-output components. For example, input-output devices 22 may include touch sensors, displays (e.g., touch-sensitive displays and / or force-sensitive displays), light-emitting components such as displays without touch sensor capability, buttons (mechanical, capacitive, optical, etc.), scroll wheels, touchpads, keypads, keyboards, microphones, cameras, buttons, speakers, status indicators, audio jacks and other audio port components, digital data port devices, motion sensors (accelerometers, gyroscopes, and / or compasses for detecting motion), capacitive sensors, proximity sensors, magnetic sensors, force sensors (e.g., force sensors coupled to a display to detect pressure applied to the display), temperature sensors, etc. In some configurations, keyboards, headphones, displays, pointing devices such as touchpads, mice and joysticks, and other input-output devices may be coupled to device 10 via wired or wireless connections (e.g., some input-output devices in input-output devices 22 may be peripheral devices coupled to the main processing unit or other parts of device 10 via wired or wireless links).

[0027] The input-output circuitry 20 may include a wireless circuitry 24 to support wireless communication. The wireless circuitry 24 (sometimes referred to herein as wireless communication circuitry 24) may include one or more antennas 30.

[0028] Wireless circuit 24 may also include transceiver circuitry 26. Transceiver circuitry 26 may include transmitter circuitry, receiver circuitry, modulator circuitry, demodulator circuitry (e.g., one or more modems), radio frequency circuitry, one or more radios, intermediate frequency circuitry, optical transmitter circuitry, optical receiver circuitry, optical light source, other optical components, baseband circuitry (e.g., one or more baseband processors), amplifier circuitry, clock circuitry such as one or more local oscillators and / or phase-locked loops, memory, one or more registers, filter circuitry, switching circuitry, analog-to-digital converter (ADC) circuitry, digital-to-analog converter (DAC) circuitry, radio frequency transmission lines, optical fibers, and / or any other circuitry for transmitting and / or receiving wireless signals using antenna 30. Components of transceiver circuitry 26 may be implemented on a single integrated circuit, chip, system-on-a-chip (SOC), die, printed circuit board, substrate, or package, or components of transceiver circuitry 26 may be distributed across two or more integrated circuits, chips, SOCs, printed circuit boards, substrates, and / or packages.

[0029] Figure 1 The examples are merely illustrative. Although for clarity, in Figure 1In the example, control circuitry 14 is shown separate from wireless circuitry 24, but wireless circuitry 24 may include processing circuitry (e.g., one or more processors) and / or storage circuitry, the processing circuitry forming part of processing circuitry 18, and the storage circuitry forming part of storage circuitry 16 of control circuitry 14 (e.g., portions of control circuitry 14 may be implemented on wireless circuitry 24). As an example, control circuitry 14 may include baseband circuitry (e.g., one or more baseband processors), digital control circuitry, analog control circuitry, and / or other control circuitry forming part of wireless circuitry 24. Baseband circuitry may, for example, access the communication protocol stack on control circuitry 14 (e.g., storage circuitry 20) to: perform user plane functions at the PHY layer, MAC layer, RLC layer, PDCP layer, SDAP layer, and / or PDU layer; and / or perform control plane functions at the PHY layer, MAC layer, RLC layer, PDCP layer, RRC layer, and / or non-access layer.

[0030] Transceiver circuitry 26 can be coupled to each antenna 30 in wireless circuitry 24 via corresponding signal paths 28. Each signal path 28 may include one or more RF transmit lines, waveguides, optical fibers, and / or any other desired lines / paths for transmitting wireless signals between transceiver circuitry 26 and antenna 30. Antenna 30 may be formed using any desired antenna structure for transmitting wireless signals. For example, antenna 30 may include antennas with resonant elements, formed by dipole antenna structures, planar dipole antenna structures (e.g., butterfly antenna structures), slot antenna structures, loop antenna structures, patch antenna structures, inverted F-shaped antenna structures, planar inverted F-shaped antenna structures, helical antenna structures, monopole antennas, dipoles, hybrids of these designs, etc. Filter circuitry, switching circuitry, impedance matching circuitry, and / or other antenna tuning components may be adjusted to modify the frequency response and wireless performance of antenna 30 over time.

[0031] If desired, two or more antennas in antenna 30 may be integrated into a phased antenna array (sometimes referred to herein as a phased array antenna), in which each antenna transmits a wireless signal having a corresponding phase and magnitude adjusted over time, thus causing constructive and destructive interference of the wireless signals to generate (form) a signal beam in a given pointing direction. As used herein, the term "transmitting a wireless signal" means the transmission and / or reception of a wireless signal (e.g., for performing one-way and / or two-way wireless communication with an external wireless communication device). Antenna 30 may transmit a wireless signal by radiating the signal into free space (or radiating it into free space through an intermediary device structure such as a dielectric overlay). Alternatively or in addition, antenna 30 may receive a wireless signal from free space (e.g., through an intermediary device structure such as a dielectric overlay). The transmission and reception of wireless signals by antenna 30 each involve the excitation or resonance of an antenna current on an antenna resonant (radiating) element in the antenna by the wireless signal within the antenna's operating frequency band.

[0032] Transceiver circuitry 26 may use antenna 30 to transmit and / or receive wireless signals that transmit wireless communication data between device 10 and external wireless communication equipment (e.g., one or more other devices, such as device 10, a wireless access point, or a base station). The wireless communication data may be transmitted bidirectionally or unidirectionally. The wireless communication data may include, for example, data encoded into corresponding data packets, such as wireless data associated with telephone calls, streaming media content, internet browsing, wireless data associated with software applications running on device 10, email messages, etc.

[0033] Alternatively, wireless circuitry 24 may use antenna 30 to perform wireless sensing operations. Sensing operations may allow device 10 to detect (e.g., sense or identify) the presence, location, orientation, and / or speed (motion) of an external object. Control circuitry 14 may use the detected presence, location, orientation, and / or speed of the external object to perform any desired device operation. As an example, control circuitry 14 may use the detected presence, location, orientation, and / or speed of an external object to identify corresponding user input for one or more software applications running on device 10, such as gesture input performed by the user's hand or other body parts or by an external stylus, game controller, head-mounted device, or other peripheral device or accessory; determine when one or more antennas 30 need to be disabled or set with a reduced maximum transmit power level (e.g., to meet regulatory restrictions on radio frequency exposure); determine how to guide (form) the radio frequency signal beam generated by antennas 30 for wireless circuitry 24 (e.g., in the case where antennas 30 include a phased array of antennas 30); map or model the environment around device 10 (e.g., to generate a software model of the room where device 10 is located for use by augmented reality applications, gaming applications, mapping applications, home design applications, engineering applications, etc.); detect the presence of obstacles near (e.g., around) device 10 or in the direction of movement of the user of device 10; etc.

[0034] Wireless circuit 24 can transmit and / or receive wireless signals within a corresponding frequency band of the electromagnetic spectrum (sometimes referred to herein as the communication band or simply the "band"). The frequency band handled by communication circuit 26 may include: the wireless local area network (WLAN) band (e.g., Wi-Fi). ® (IEEE 802.11) or other WLAN communication bands such as the 2.4 GHz WLAN band (e.g., 2400 MHz to 2480 MHz), the 5 GHz WLAN band (e.g., 5180 MHz to 5825 MHz), Wi-Fi ® 6E band (e.g., 5925MHz-7125MHz) and / or other Wi-Fi ® Bands (e.g., 1875MHz-5160MHz); Wireless Personal Area Network (WPAN) bands such as 2.4GHz Bluetooth. ®Bands or other WPAN communication bands; cellular telephone bands (e.g., bands from about 600 MHz to about 5 GHz, 3G bands, 4G LTE bands, 5G New Radio Frequency Range 1 (FR1) band below 10 GHz, 5G New Radio Frequency Range 2 (FR2) band between 20 GHz and 60 GHz, etc.); other centimeter wave or millimeter wave bands between 10 GHz and 100 GHz; near-field communication bands (e.g., 13.56 MHz); satellite navigation bands (e.g., GPS band from 1565 MHz to 1610 MHz, Global Navigation Satellite System (GLONASS) band, BeiDou Navigation Satellite System (BDS) band, etc.); ultra-wideband (UWB) bands operating under the IEEE 802.15.4 protocol and / or other ultra-wideband communication protocols; communication bands belonging to the 3GPP wireless communication standards family; communication bands belonging to the IEEE 802.XX standards family; and / or any other desired bands of interest.

[0035] Over time, software applications on electronic devices (such as device 10) have become increasingly data-intensive. Therefore, the wireless circuitry on these devices needs to support data transmission at increasingly higher data rates. Generally, the data rate supported by a wireless circuit is proportional to the frequency of the wireless signal transmitted by the circuit (e.g., higher frequencies support higher data rates compared to lower frequencies). Wireless circuit 24 can transmit centimeter and millimeter wave signals to support relatively high data rates (e.g., because centimeter and millimeter wave signals are at relatively high frequencies between approximately 10 GHz and 100 GHz). However, the data rates supported by centimeter and millimeter wave signals may still be insufficient to meet all the data transmission needs of device 10. To support even higher data rates, such as up to 5 Gbps-10 Gbps or higher, wireless circuit 24 can transmit wireless signals at frequencies greater than 100 GHz.

[0036] like Figure 1As shown, wireless circuit 24 can transmit wireless signals 32 at frequencies greater than approximately 100 GHz and can receive wireless signals 34 at frequencies greater than approximately 100 GHz. Wireless signals 32 and 34 may be referred to herein as extremely high frequency (THF) signals 32 and 34, sub-THz signals 32 and 34, THz signals 32 and 34, or sub-millimeter wave signals 32 and 34. THF signals 32 and 34 may be located at sub-THz frequencies or THz frequencies such as those between 100 GHz and 1 THz, between 100 GHz and 10 THz, between 100 GHz and 2 THz, between 200 GHz and 1 THz, between 300 GHz and 1 THz, between 300 GHz and 2 THz, between 300 GHz and 10 THz, between 100 GHz and 800 GHz, between 200 GHz and 1.5 THz, etc. (e.g., within sub-THz, THz, THF, or sub-millimeter bands such as the 6 GHz band). The high data rates supported by these frequencies can be utilized by device 10 to perform cellular phone voice and / or data communications (e.g., simultaneously supporting spatial multiplexing to provide additional data bandwidth), to perform spatial ranging operations such as radar operations to detect the presence, location, and / or speed of objects outside device 10, to perform vehicle sensing (e.g., with enhanced security), to perform health / body monitoring of the user of device 10 or another person, to perform gas or chemical detection, to establish a high data rate wireless connection between device 10 and another device or peripheral device (e.g., to establish a high data rate between a display driver on device 10 and a display showing ultra-high resolution video), to establish a remote wireless head (e.g., flexible high data rate connection), to establish a THF chip-to-chip connection supporting high data rates within device 10 (e.g., where an antenna 30 on a first chip in device 10 transmits a THF signal 32 to another antenna 30 on a second chip in device 10), and / or to perform any other desired high data rate operations.

[0037] Space is extremely valuable within electronic devices (such as device 10). In some cases, the antenna 30 used to transmit the THF signal 32 is different from the antenna 30 used to receive the THF signal 34. However, using different antennas 30 to handle the transmission of the THF signal 32 and the reception of the THF signal 34 can consume excessive space and other resources within device 10, as two antennas 30 and signal path 28 would be required to handle both transmission and reception. To minimize space and resource consumption within device 10, the same antenna 30 and signal path 28 can be used for both transmitting the THF signal 32 and receiving the THF signal 34. If needed, multiple antennas 30 in wireless circuit 24 can transmit the THF signal 32 and receive the THF signal 34. The antennas can be integrated into a phased antenna array that transmits the THF signal 32 and receives the THF signal 34 within the corresponding signal beam oriented in the selected beam pointing direction.

[0038] Integrating components into the wireless circuitry 24 that supports wireless communication at these high frequencies can be challenging. If desired, the transceiver circuitry 26 and signal path 28 may include optical components that transmit optical signals to support the transmission of THF signal 32 and the reception of THF signal 34 in a space- and resource-efficient manner. The optical signals can be used to transmit THF signal 32 at the THF frequency and to receive THF signal 34 at the THF frequency.

[0039] Figure 2 This is a diagram of an exemplary antenna 30 that can be used to transmit THF signal 32 and receive THF signal 34 using optical signals. Antenna 30 may include one or more antenna radiating (resonant) elements, such as radiating (resonant) element arms 36. Figure 2 In the example, antenna 30 is a planar dipole antenna (sometimes referred to as a "butterfly" antenna) with two opposing radiating element arms 36 (e.g., butterfly arms or dipole arms). This is merely illustrative, and in general, antenna 30 can be any type of antenna with any desired antenna radiating element architecture.

[0040] like Figure 2As shown, antenna 30 includes photodiodes (PDs) 42 coupled between radiating element arms 36. Electronic devices (such as device 10) including antenna 30 with photodiodes 42 may sometimes also be referred to as electro-optical devices (e.g., electro-optical device 10). Photodiode 42 may be a programmable photodiode. For example, an example of a programmable single-line carrier photodiode (UTC PD) is described herein. Therefore, photodiode 42 may sometimes be referred to herein as UTCPD 42 or programmable UTC PD 42. This is merely illustrative, and in general, photodiode 42 may include any desired type of adjustable / programmable photodiode or component that converts electromagnetic energy (e.g., light or optical energy) at optical frequencies (e.g., infrared frequencies, visible light frequencies, and / or ultraviolet frequencies) into current at THF frequencies on the radiating element arms 36 and / or vice versa. Each radiating element arm 36 may, for example, have a first edge located at the UTC PD 42 and a second edge wider than the first edge opposite to the first edge (e.g., in a specific embodiment where antenna 30 is a butterfly antenna). Other radiating elements may be used if necessary.

[0041] The UTC PD 42 may be able to receive one or more control signals V 偏置 Bias terminal 38. Control signal V 偏置 This may include bias voltages set at one or more voltage levels and / or other control signals for controlling the operation of the UTC PD 42, such as impedance adjustment control signals for adjusting the output impedance of the UTC PD 42. Control circuit 14 ( Figure 1 Control signals V can be provided (e.g., applied, supplied, asserted, etc.) with different settings (e.g., value, quantity, etc.). 偏置 This allows for dynamic control (e.g., programming or adjustment) of the operation of the UTC PD 42 over time. For example, the control signal V... 偏置 This can be used to control whether antenna 30 transmits THF signal 32 or receives THF signal 34. When the control signal V... 偏置 When the bias voltage asserted at the first level or magnitude is present, antenna 30 can be configured to transmit THF signal 32. When the control signal V... 偏置 When the bias voltage asserted at the second level or magnitude is present, antenna 30 can be configured to receive THF signal 34. Figure 2 In the example, the control signal V 偏置 This includes a bias voltage asserted at the first level to configure antenna 30 to transmit THF signal 32. If necessary, control signal V... 偏置It can also be adjusted to control the waveform of the THF signal (e.g., as a square function, linear function, etc. that preserves the modulation of the incident optical signal) to perform gain control on the signal transmitted by the antenna 30 and / or to adjust the output impedance of the UTC PD 42.

[0042] like Figure 2 As shown, the UTC PD 42 can be optically coupled to optical path 40. Optical path 40 may include one or more optical fibers or waveguides. The UTC PD 42 can be transmitted from transceiver circuit 26 via optical path 40. Figure 1 The transceiver circuit 26 receives optical signals. These optical signals may include a first optical local oscillator (LO) signal LO1 and a second optical local oscillator (LO2) signal. The optical local oscillator signals LO1 and LO2 can be received by the transceiver circuit 26. Figure 1 The light source is generated in the antenna 30. Optical local oscillator signals LO1 and LO2 can be at optical wavelengths (e.g., between 400 nm and 700 nm), ultraviolet wavelengths (e.g., near-ultraviolet or extreme ultraviolet wavelengths), and / or infrared wavelengths (e.g., near-infrared, mid-infrared, or far-infrared wavelengths). Optical local oscillator signal LO2 can be offset from optical local oscillator signal LO1 by a wavelength offset X. The wavelength offset X can be equal to the wavelength of the THF signal transmitted by antenna 30 (e.g., between 100 GHz and 1 THz (1000 GHz), between 100 GHz and 2 THz, between 300 GHz and 800 GHz, between 300 GHz and 1 THz, between 300 GHz and 400 GHz, etc.).

[0043] During signal transmission, radio data (e.g., radio data packets, symbols, frames, etc.) can be modulated onto an optical local oscillator signal LO2 to generate a modulated optical local oscillator signal LO2'. If desired, the optical local oscillator signal LO1 can be provided with an optical phase shift S. The optical path 40 can illuminate the UTC PD 42 using the optical local oscillator signal LO1 (plus the applied optical phase shift S) and the modulated optical local oscillator signal LO2'. If desired, a lens or other optical component can be inserted between the optical path 40 and the UTC PD 42 to help focus the optical local oscillator signal onto the UTC PD 42.

[0044] The UTC PD 42 converts the optical local oscillator signal LO1 and the modulated local oscillator signal LO2' (e.g., the beat between the two optical local oscillator signals) into an antenna current flowing along the periphery of the radiating element arm 36. The frequency of the antenna current is equal to the frequency difference between the local oscillator signal LO1 and the modulated local oscillator signal LO2'. The antenna current radiates (emits) the THF signal 32 into free space. Control signal V偏置 The UTC PD 42 can be controlled to convert the optical local oscillator signal into an antenna current on the radiating element arm 36, while simultaneously modulating and thus storing the radio data on the modulated local oscillator signal LO2' (e.g., by applying a square function to the signal). The THF signal 32 will then carry the modulated radio data for reception and demodulation by external wireless communication equipment.

[0045] Figure 3 To illustrate (for example, in the case of control signal V) 偏置 The settings from Figure 2 The diagram shows how antenna 30 can receive THF signal 34 after the transmit state is changed to receive state. Figure 3 As shown, a THF signal 34 can be incident on the antenna radiating element arm 36. The incident THF signal 34 can generate an antenna current flowing around the periphery of the radiating element arm 36. The UTC PD 42 can use an optical local oscillator signal LO1 (plus an optical phase shift S for the application), an optical local oscillator signal LO2 (e.g., without modulation), and a control signal V. 偏置 (For example, the bias voltage asserted at the second level) converts the received THF signal 34 into an intermediate frequency signal SIGIF output to the intermediate frequency signal path 44.

[0046] The frequency of the intermediate frequency signal SIGIF can be equal to the frequency of the THF signal 34 minus the difference between the frequencies of the optical local oscillator signal LO1 and the optical local oscillator signal LO2. For example, the intermediate frequency signal SIGIF can be at a lower frequency than the THF signals 32 and 34, such as centimeter or millimeter wave frequencies between 10 GHz and 100 GHz, between 30 GHz and 80 GHz, or approximately 60 GHz. If needed, when switching from transmit to receive or vice versa, the transceiver circuit 26 ( Figure 1 The frequency of the optical local oscillator signal LO1 and / or optical local oscillator signal LO2 can be changed. The UTC PD 42 can modulate and store the data of the THF signal 34 in the intermediate signal SIGIF. Transceiver circuit 26 ( Figure 1 The receiver in the circuit 24 can demodulate the intermediate frequency (IF) signal SIGIF (e.g., after further downconversion) to recover radio data from the THF signal 34. Alternatively, the wireless circuit 24 can convert the IF signal SIGIF to the optical domain before recovering the radio data. Alternatively, the IF signal path 44 can be omitted, and the UTCPD 42 can convert the THF signal 34 to the optical domain for subsequent demodulation and data recovery (e.g., in the sidebands of the optical signal).

[0047] Figure 2 and Figure 3Antenna 30 can support the transmission of THF signal 32 and the reception of THF signal 34 using a given polarization (e.g., linear polarization such as vertical polarization). If needed, wireless circuit 24 ( Figure 1 It may include multiple antennas 30 for covering different polarizations. Figure 4 This is a diagram illustrating an example of how wireless circuit 24 can include multiple antennas 30 for covering different polarizations.

[0048] like Figure 4 As shown, the wireless circuit may include a first antenna 30, such as antenna 30V for covering a first polarization (e.g., a first linear polarization such as vertical polarization), and may include a second antenna 30, such as antenna 30H for covering a second polarization different from or orthogonal to the first polarization (e.g., a second linear polarization such as horizontal polarization). Antenna 30V may have a UTC PD 42, such as UTC PD 42V coupled between corresponding pairs of radiating element arms 36. Antenna 30H may have a UTC PD 42, such as UTC PD 42H coupled between corresponding pairs of radiating element arms 36, which are oriented non-parallel (e.g., orthogonally) to the radiating element arms 36 in antenna 30V. This allows antennas 30V and 30H to transmit THF signals 32 with corresponding (orthogonal) polarizations, and allows antennas 30V and 30H to receive THF signals 32 with corresponding (orthogonal) polarizations.

[0049] To minimize space within device 10, antenna 30V may be vertically stacked above or below antenna 30H (e.g., where UTC PD 42V and UTC PD 42H partially or completely overlap). In this example, both antennas 30V and 30H may be formed on the same substrate, such as a rigid or flexible printed circuit board. The substrate may include multiple stacked dielectric layers (e.g., layers of ceramic, epoxy, flexible printed circuit board material, rigid printed circuit board material, etc.). The radiating element arm 36 in antenna 30V may be formed on a separate substrate layer as the radiating element arm 36 in antenna 30H, or the radiating element arm 36 in antenna 30V may be formed on the same substrate layer as the radiating element arm 36 in antenna 30H. UTC PD 42V may be formed on the same substrate layer as UTC PD 42H, or UTC PD 42V may be formed on a separate substrate layer as UTC PD 42H. The UTC PD 42V can be formed on the same substrate as the radiating element arm 36 in the antenna 30V, or it can be formed on a separate substrate. The UTC PD 42H can be formed on the same substrate as the radiating element arm 36 in the antenna 30H, or it can be formed on a separate substrate.

[0050] If needed, antenna 30 or Figure 4 The antennas 30H and 30V are integrated into the phased antenna array. Figure 5 This diagram illustrates an example of how antennas 30H and 30V can be integrated within a phased antenna array. (See diagram for example.) Figure 5 As shown, device 10 may include a phased antenna array 46 of stacked antennas 30H and 30V arranged in a rectangular grid of rows and columns. Each of these antennas in phased antenna array 46 may be formed on the same substrate. This is merely illustrative. In general, phased antenna array 46 (sometimes referred to as phased array antenna) may include any desired number of antennas 30V and 30H (or non-stacked antennas 30) arranged in any desired pattern. Each of these antennas in phased antenna array 46 may be provided with a corresponding optical phase shift S ( Figure 2 and Figure 3 The corresponding optical phase shift configures the antenna to jointly transmit THF signal 32 and / or receive THF signal 34, which are summed to form a signal beam of the THF signal in the desired beam pointing direction. The beam pointing direction can be selected to direct the signal beam toward external communication equipment, toward a desired external object, away from an external object, etc.

[0051] The phased antenna array 46 can occupy a relatively small space within the device 10. For example, each antenna 30V / 30H can have a length of 48 (e.g., measured from one end of a radiating element arm to the opposite end of the opposite radiating element arm). The length 48 can be approximately equal to half the wavelength of the THF signals 32 and 34. For example, the length 48 can be as small as 0.5 mm or less. Each UTC-PD 42 in the phased antenna array 46 can occupy a lateral area of ​​100 square micrometers or less. This allows the phased antenna array 46 to occupy a very small area within the device 10, thus allowing the phased antenna array to be integrated within different parts of the device 10 while still allowing other space for device components. Figures 2 to 5 The examples are merely illustrative, and in general, each antenna can have any desired antenna radiating element architecture.

[0052] Figure 6 To illustrate a given antenna 30 and signal path 28 ( Figure 1 This is a circuit diagram showing how THF signal 32 can be used to transmit and receive THF signal 34 based on an optical local oscillator signal. Figure 6 In the example, the UTC PD 42 converts the received THF signal 34 into an intermediate frequency signal SIGIF, which is then converted to the optical domain for use in recovering wireless data from the received THF signal.

[0053] like Figure 6As shown, wireless circuit 24 may include transceiver circuitry 26 coupled to antenna 30 via signal path 28 (e.g., an optical signal path, sometimes referred to herein as optical signal path 28). UTC PD 42 may be coupled between radiating element arm 36 of antenna 30 and signal path 28. Transceiver circuitry 26 may include optical components 68, amplifier circuitry such as power amplifier 76, and digital-to-analog converter (DAC) 74. Optical components 68 may include optical receivers (such as optical receiver 72) and optical local oscillator (LO) light sources (emitters) 70. LO light sources 70 may include two or more light sources (e.g., sources of electromagnetic energy, light, or optical energy), such as laser sources, laser diodes, optical phase-locked loops, or other optical emitters that emit light (e.g., electromagnetic energy, light, or optical energy including optical local oscillator signals LO1 and LO2) at corresponding wavelengths (e.g., visible wavelengths, infrared wavelengths, and / or ultraviolet wavelengths). If desired, LO light sources 70 may include a single light source and may include optical components for splitting the light emitted by the light source into different wavelengths. Signal path 28 can be coupled to optical component 68 via optical path 66. Optical path 66 may include one or more optical fibers and / or waveguides.

[0054] Signal path 28 may include a beam splitter such as beam splitter (OS) 54, optical paths such as optical path 64 and optical path 62, an optical combiner such as optical combiner (OC) 52, and optical path 40. Optical path 62 may be an optical fiber or a waveguide. Optical path 64 may be an optical fiber or a waveguide. Beam splitter 54 may have a first (e.g., input) port coupled to optical path 66, a second (e.g., output) port coupled to optical path 62, and a third (e.g., output) port coupled to optical path 64. Optical path 64 may couple beam splitter 54 to a first (e.g., input) port of optical combiner 52. Optical path 62 may couple beam splitter 54 to a second (e.g., input) port of optical combiner 52. Optical combiner 52 may have a third (e.g., output) port coupled to optical path 40.

[0055] An optical phase shifter (such as optical phase shifter 80) may be (optically) inserted on or along optical path 64. An optical modulator (such as optical modulator 56) may be (optically) inserted on or along optical path 62. Optical modulator 56 may be, for example, a Mach-Zehnder modulator (MZM), and is therefore sometimes referred to as MZM 56. MZM 56 includes a first optical arm (branch) 60 and a second optical arm (branch) 58 inserted in parallel along optical path 62. The propagation of the optical local oscillator signal LO2 along arms 60 and 58 of MZM 56 allows for different optical phase shifts to be applied to each arm before the signal is reassembled at the output of the MZM (e.g., where the optical phase modulation generated on these arms is converted into intensity modulation at the output of MZM 56) in the presence of a voltage signal applied to one or both arms. When the voltage applied to MZM 56 includes radio data, MZM 56 can modulate the radio data onto the optical local oscillator signal LO2. If needed, the phase shift performed at MZM 56, as a supplement to or alternative to optical phase shifter 80, can be used to perform beamforming / guiding. MZM 56 can receive one or more bias voltages W applied to one or both of arms 58 and 60. 偏置 (Sometimes referred to in this paper as the bias signal W) 偏置 Control circuit 14 ( Figure 1 ) can provide bias voltages W with different values. 偏置 This allows the MZM 56 to be placed in different operating modes (e.g., an operating mode that suppresses the optical carrier signal, an operating mode that does not suppress the optical carrier signal, etc.).

[0056] Intermediate frequency (IF) signal path 44 may couple UTC PD 42 to MZM 56 (e.g., arm 60). An amplifier (such as low-noise amplifier 82) may be inserted into IF signal path 44. IF signal path 44 may be used to pass the IF signal SIGIF from UTC PD 42 to MZM 56. DAC 74 may have inputs coupled to up-conversion circuitry, modulator circuitry, and / or baseband circuitry in the transmitter of transceiver circuitry 26. DAC 74 may receive digital data for transmission via antenna 30 and may convert digital data into the analog domain (e.g., as data DAT). DAC 74 may have an output coupled to transmit data path 78. Transmit data path 78 may couple DAC 74 to MZM 56 (e.g., arm 60). Each component along signal path 28 allows the same antenna 30 to transmit THF signal 32 and receive THF signal 34 (e.g., using the same component along signal path 28), thereby minimizing space and resource consumption within device 10.

[0057] The LO light source 70 can generate (emit) optical local oscillator signals LO1 and LO2 (e.g., at different wavelengths separated by the wavelengths of the THF signals 32 / 34). Optical components 68 may include lenses, waveguides, optical couplers, optical fibers, and / or other optical components that guide the emitted optical local oscillator signals LO1 and LO2 via optical path 66 toward beam splitter 54. Beam splitter 54 can split the optical signals on optical path 66 (e.g., according to wavelength) to output optical local oscillator signal LO1 onto optical path 64, while outputting optical local oscillator signal LO2 onto optical path 62.

[0058] Control circuit 14 ( Figure 1 A phase control signal CTRL can be provided to optical phase shifter 80. The phase control signal CTRL controls optical phase shifter 80 to apply an optical phase shift S to the optical local oscillator signal LO1 on optical path 64. The phase shift S can be selected to guide the signal beam of THF signals 32 / 34 in the desired pointing direction. Optical phase shifter 80 can pass the phase-shifted optical local oscillator signal LO1 (referred to as LO1 + S) to optical combiner 52. Signal beamguiding is performed in the optical domain (e.g., using optical phase shifter 80) rather than in the THF domain because there is no satisfactory phase shifting circuit component operating at a frequency as high as that of THF signals 32 and 34. Optical combiner 52 can receive optical local oscillator signal LO2 via optical path 62. Optical combiner 52 can combine optical local oscillator signals LO1 and LO2 onto optical path 40, which directs these optical local oscillator signals to UTC PD 42 for use during signal transmission or reception.

[0059] During the transmission of THF signal 32, DAC 74 can receive digital radio data (e.g., data packets, frames, symbols, etc.) for transmission via THF signal 32. DAC 74 can convert the digital radio data into the analog domain and output (transmit) the data as data DAT to transmit data path 78 (e.g., for transmission via antenna 30). Power amplifier 76 can amplify data DAT. Transmit data path 78 can pass data DAT to MZM 56 (e.g., arm 60). MZM 56 can modulate data DAT onto optical local oscillator signal LO2 to generate modulated optical local oscillator signal LO2' (e.g., an optical local oscillator signal at the frequency / wavelength of optical local oscillator signal LO2 but modulated to include data identified by data DAT). Optical combiner 52 can combine optical local oscillator signal LO1 with modulated optical local oscillator signal LO2' at optical path 40.

[0060] Optical path 40 can illuminate UTC PD 42 using optical local oscillator signal LO1 (e.g., and phase shift S applied by optical phase shifter 80) and modulated optical local oscillator signal LO2'. Control circuit 14 ( Figure 1 Control signals V can be applied to UTCPD 42. 偏置 The control signal configures antenna 30 to transmit THF signal 32. UTC PD 42 can convert the optical local oscillator signal LO1 and the modulated optical local oscillator signal LO2' into an antenna current on the radiating element arm 36 at the frequency of THF signal 32 (e.g., when programmed to use control signal V). 偏置 (During transmission). The antenna current on radiating element arm 36 can radiate a THF signal 32. The frequency of the THF signal 32 is given by the frequency difference between the optical local oscillator signal LO1 and the modulated optical local oscillator signal LO2'. Control signal V 偏置 The UTC PD 42 can be controlled to preserve the modulation from the modulated optical local oscillator signal LO2' in the radiated THF signal 32. External equipment receiving the THF signal 32 can thus be able to extract data DAT from the THF signal 32 emitted by the antenna 30.

[0061] During the reception of THF signal 34, MZM 56 does not modulate any data onto the optical local oscillator signal LO2. Optical path 40 therefore illuminates UTC PD 42 using optical local oscillator signal LO1 (e.g., and phase shift S) and optical local oscillator signal LO2. Control circuit 14 ( Figure 1 A control signal V can be applied to the UTC PD 42. 偏置 (e.g., bias voltage), this control signal configures antenna 30 to receive THF signal 32. UTC PD 42 can use optical local oscillator signals LO1 and LO2 to convert the received THF signal 34 into an intermediate frequency signal SIGIF (e.g., when programmed to use bias voltage V) output to the intermediate frequency signal path 44. 偏置 (During reception). The intermediate frequency signal SIGIF may include modulated data from the received THF signal 34. The low-noise amplifier 82 amplifies the intermediate frequency signal SIGIF, which is then provided to the MZM 56 (e.g., arm 60). The MZM 56 can convert the intermediate frequency signal SIGIF as an optical signal LORx to the optical domain (e.g., by modulating the data in the intermediate frequency signal SIGIF onto one of these optical local oscillator signals), and can pass these optical signals to the optical receiver 72 in the optical component 68, as indicated by arrow 63 (e.g., via optical paths 62 and 66 or other optical paths). Control circuit 14 ( Figure 1The optical receiver 72 can be used to convert the optical signal LORx into other formats and recover (demodulate) the data carried by the THF signal 34 from the optical signal. In this way, the same antenna 30 and signal path 28 can be used to transmit and receive THF signals, while also performing beamguiding operations.

[0062] Figure 6 The example of the intermediate frequency (IF) signal SIGIF being converted to the optical domain is merely illustrative. If needed, transceiver circuitry 26 can receive and demodulate the IF signal SIGIF without first transmitting these signals to the optical domain. For example, transceiver circuitry 26 may include an analog-to-digital converter (ADC), with the IF signal path 44 coupled to the input of the ADC instead of the MZM56, and the ADC converting the IF signal SIGIF to the digital domain. Alternatively, the IF signal path 44 may be omitted, and the control signal V... 偏置 The UTC PD 42 can be controlled to directly sample the THF signal 34 along with the optical local oscillator signals LO1 and LO2 into the optical domain. For example, the UTC PD 42 can use the received THF signal 34 and the control signal V 偏置 An optical signal is generated on optical path 40. The optical signal may have an optical carrier with sidebands separated from the optical carrier by a fixed frequency offset (e.g., 30GHz-100GHz, 60GHz, 50GHz-70GHz, 10GHz-100GHz, etc.). The sidebands may be used to carry modulated data from the received THF signal 34. Signal path 28 may guide (propagate) the optical signal generated by UTC PD 42 to optical receiver 72 in optical component 68 (e.g., via optical paths 40, 64, 62, 66, 63 and / or other optical paths). Control circuit 14 ( Figure 1 The optical receiver 72 can be used to convert the optical signal into other formats and recover (demodulate) the data carried by the THF signal 34 from the optical signal (e.g., from the sideband of the optical signal).

[0063] If desired, optical component 68 may include clock circuitry, such as one or more electro-optical phase-locked loops. Figure 6 As shown, optical component 68 may include an electro-optical phase-locked loop (OPLL) circuit, such as OPLL 75 (sometimes referred to herein as an opto-phase-locked loop). OPLL 75 can be used to control and time the LO light source 70 and / or to time any other desired hardware in device 10 (e.g., OPLL 75 does not necessarily have to be located in transceiver 26 and may generally be located elsewhere in device 10). The LO light source 70 may, for example, generate an optical LO signal that is phase-locked and frequency-locked relative to each other using OPLL 75.

[0064] Figure 7The circuit diagram illustrates an example of how multiple antennas 30 can be integrated into a phased antenna array 88 that transmits THF signals via corresponding signal beams. Figure 7 In the example, for clarity, Figure 6 The MZM56, intermediate frequency signal path 44, data path 78, and optical receiver 72 have been omitted. Each of these antennas in the phased antenna array 88 may optionally sample the received THF signal directly into the optical domain, or may pass the intermediate frequency signal SIGIF to the ADC in the transceiver circuit 26.

[0065] like Figure 7 As shown, the phased antenna array 88 includes N antennas 30, such as a first antenna 30-0, a second antenna 30-1, and an Nth antenna 30-(N-1). Each antenna 30 in the phased antenna array 88 can be transmitted via a corresponding optical signal path (e.g., Figure 6 The optical signal path 28) is coupled to the optical component 68. Each of the N signal paths may include a corresponding optical combiner 52, which is coupled to the UTC PD 42 of the corresponding antenna 30 (e.g., the UTC PD 42 in antenna 30-0 may be coupled to optical combiner 52-0, the UTC PD 42 in antenna 30-1 may be coupled to optical combiner 52-1, the UTC PD 42 in antenna 30-(N-1) may be coupled to optical combiner 52-(N-1), etc.). Each of the N signal paths may also include a corresponding optical path 62 and a corresponding optical path 64, which are coupled to a corresponding optical combiner 52 (e.g., optical paths 64-0 and 62-0 may be coupled to optical combiner 52-0, optical paths 64-1 and 62-1 may be coupled to optical combiner 52-1, optical paths 64-(N-1) and 62-(N-1) may be coupled to optical combiner 52-(N-1), etc.).

[0066] Optical components 68 may include LO light sources 70, such as a first LO light source 70A and a second LO light source 70B. Optical signal paths for each antenna in the antennas 30 of the phased antenna array 88 may share one or more beam splitters 54, such as a first beam splitter 54A and a second beam splitter 54B. LO light source 70A may generate (e.g., produce, emit, transmit, etc.) a first optical local oscillator signal LO1 and may provide the first optical local oscillator signal LO1 to beam splitter 54A via optical path 66A. Beam splitter 54A may distribute the first optical local oscillator signal LO1 to each UTC PD in the UTC PD 42 of the phased antenna array 88 via optical path 64 (e.g., optical paths 64-0, 64-1, 64-(N-1) etc.). Similarly, LO light source 70B may generate (e.g., produce, emit, transmit, etc.) a second optical local oscillator signal LO2 and may provide the second optical local oscillator signal LO2 to beam splitter 54B via optical path 66B. The beam splitter 54B can distribute the second optical local oscillator signal LO2 to each UTC PD in the UTCPD 42 of the phased antenna array 88 via optical path 62 (e.g., optical paths 62-0, 62-1, 62-(N-1) etc.).

[0067] The corresponding optical phase shifter 80 can be inserted along each optical path 64 (on which) (for example, the first optical phase shifter 80-0 can be inserted along optical path 64-0, the second optical phase shifter 80-1 can be inserted along optical path 64-1, the Nth optical phase shifter 80-(N-1) can be inserted along optical path 64-(N-1), etc.). Each optical phase shifter 80 can receive a control signal CTRL, which controls the phase S of the optical local oscillator signal LO1 provided by the optical phase shifter (for example, the first optical phase shifter 80-0 can apply a zero-degree / radian optical phase shift to the optical local oscillator signal LO1 provided to the antenna 30-0, the second optical phase shifter 80-1 can apply an optical phase shift of Δφ to the optical local oscillator signal LO1 provided to the antenna 30-1, and the Nth optical phase shifter 80-(N-1) can apply an optical phase shift of (N-1)Δφ to the optical local oscillator signal LO1 provided to the antenna 30-(N-1). By adjusting the phase S applied by each of the N optical phase shifters 80, the control circuit 14 ( Figure 1The control circuit 14 can control each of the antennas 30 in the phased antenna array 88 to transmit a THF signal 32 and / or receive a THF signal 34 within a formed signal beam 83. The signal beam 83 can be oriented in a specific beam pointing direction (angle) 84 (e.g., the direction of the peak gain of the signal beam 83). The THF signal transmitted by the phased antenna array 88 can have a wavefront 86 orthogonal to the beam pointing direction 84. For example, the control circuit 14 can adjust the beam pointing direction 84 over time to point toward or away from external communication equipment or external objects.

[0068] The phased antenna array 88 can operate in an active mode, in which the array transmits and / or receives THF signals using optical local oscillator signals LO1 and LO2 (e.g., using phase-shifted guiding signal beam 83 provided to each antenna element). If desired, the phased antenna array 88 can also operate in a passive mode, in which the array does not transmit or receive THF signals. Instead, in passive mode, the phased antenna array 88 can be configured to form a passive reflector that reflects THF signals or other electromagnetic waves incident on device 10. In passive mode, the UTCPD 42 in the phased antenna array 88 is not illuminated by optical local oscillator signals LO1 and LO2, and the transceiver circuitry 26 does not perform modulation / demodulation, mixing, filtering, detection, modulation, and / or amplification on the incident THF signals.

[0069] Devices with processing capabilities include clock circuits, such as phase-locked loops (PLLs) that generate clock signals. Devices with THF signaling capabilities (such as device 10) are particularly sensitive to jitter (deviation from perfect periodicity) and phase noise frequency generation in the clock signal (e.g., because clock circuits consume relatively large amounts of power and chip area for THF frequencies). To minimize clock jitter, electro-optical PLLs (OPLLs) can be used (such as... Figure 6 The OPLL 75) is used to time the processing operations in device 10. As an example, this document describes the use of the OPLL 75 to time the processing operations using transceiver 26 (…). Figure 1 This is an example of timing THF communication. This is merely illustrative, and in general, the OPLL 75 can be used to time any desired processing operation in device 10, such as high-speed digital interface operation, processor calculation, sensing, automotive, input / output operation, communication at frequencies below 100 GHz such as millimeter / centimeter wave frequencies or frequencies below 10 GHz.

[0070] Figure 8 This is the circuit diagram for the OPLL 75. (Example) Figure 8As shown, OPLL 75 may include oscillators such as a reference oscillator 90, digital time converter circuitry such as a digital time converter (DTC) 92, counter circuitry such as a counter 98, mixers such as a downsampling mixer 122, filter circuitry such as a loop filter 126, a first light source such as a primary laser 116, a second light source such as a secondary laser 102, beam splitters such as beam splitters (OS) 104 and 112, and photodiodes such as a UTC PD 118.

[0071] Reference oscillator 90 may have an output coupled to the input of DTC 92 via path 94. The output of reference oscillator 90 may also be coupled to the input of counter 98 via path 94. Counter 98 may have an output coupled to the control input of secondary laser 102 via path 100. DTC 92 may have an output coupled to the input of downsampling mixer 122 via path 96. The output of downsampling mixer 122 may be coupled to the control input of secondary laser 102 via path 124. Loop filter 126 may be inserted between downsampling mixer 122 and secondary laser 102 along path 124. Secondary laser 102 may have an output coupled to beam splitter 104. Beam splitter 104 may couple secondary laser 102 to UTC PD 118 via optical path 106 (e.g., one or more optical fibers, waveguides, etc.) and may couple secondary laser 102 to output terminal 108 of OPLL 75.

[0072] The primary laser 116 may have an output coupled to the beam splitter 112. The beam splitter 112 may couple the primary laser 116 to the UTC PD 118 via an optical path 114 (e.g., one or more optical fibers, waveguides, etc.) and may couple the primary laser 116 to the output terminal 110 of the OPLL 75. Optical paths 106 and 114 may be combined into a single optical path if desired, and / or beam splitters 104 and 112 may be combined into a single beam splitter. The UTC PD 118 may have an output coupled to the input of the counter 98 via a path 120 (e.g., one or more RF transmit lines) and to the input of the downsampling mixer 122. Output terminals 108 and 110 may provide optical LO signals for timing other components in the device 10. For example, where the OPLL 75 is used with transceiver 26 ( Figure 1 In the specific implementation of timing for THF communication, terminal 108 can be coupled to optical path 62 and terminal 110 can be coupled to Figure 6 Optical path 64.

[0073] OPLL 75 may include a PLL nested within a frequency-locked loop (FLL). For example, UTC PD 118, a portion of path 120, counter 98, path 100, secondary laser 102, beam splitter 104, and optical path 106 may form an FLL as shown by FLL path 130. Alternatively, UTC PD 118, a portion of path 120, downsampling mixer 122, path 124, loop filter 126, secondary laser 102, beam splitter 104, and optical path 106 may form a PLL nested within FLL path 130, as shown by PLL path 128. FLL path 130 and PLL path 128 can be feedback paths for the secondary laser 102 (e.g., feedback paths communicatively coupling the output of the secondary laser 102 to the (control) input of the secondary laser 102, wherein the downsampling mixer 122 and its phase comparator are interposed along the feedback path formed by PLL path 128, and wherein the counter 98 and its comparator are interposed along the feedback path formed by FLL path 130). OPLL 75 can generate (e.g., generate, output, emit, etc.) an optical local oscillator signal LO1 at output terminal 110, and can generate an optical oscillator signal LO2 at output terminal 108. FLL can be used to coarsely adjust (tune) the secondary laser 102 until the secondary laser 102 is frequency-locked with the primary laser 116 (e.g., until the optical local oscillator signal LO1 and the optical local oscillator signal LO2 are frequency-locked, such that a selected / predetermined stable frequency difference exists between the two optical local oscillators). The PLL can be used to finely adjust (tune) the secondary laser 102 until it is phase-locked with the primary laser 116 (e.g., until the optical local oscillator signal LO1 is phase-locked with the optical local oscillator signal LO2). The frequency and phase-locked optical local oscillator signal can be used to time other components in the device 10 (e.g., the wireless circuit 24 for transmitting and / or receiving THF signals) with very low jitter and very low phase noise.

[0074] Although described herein as a laser, the primary laser 116 and the secondary laser 102 can be any desired light source / emitter. For example, lasers 116 and 102 can form Figure 7 The LO light source 70, and / or can be formed separately Figure 7The LO light sources are 70A and 70B. The primary laser 116 is sometimes referred to as a leader laser, while the secondary laser 102 is sometimes referred to as a slave laser. The primary laser 116 can emit an optical local oscillator signal LO1' at a fixed frequency / wavelength (e.g., the primary laser 116 can be a fixed (non-adjustable) laser with a fixed frequency). On the other hand, the secondary laser 102 can emit an optical local oscillator signal LO2' at an adjustable / programmable frequency / wavelength (e.g., the secondary laser 102 can be an adjustable / programmable laser). Control signals received by the secondary laser 102 via paths 124 and 100 can be used to adjust / program the frequency of the optical local oscillator signal LO2'. The wavelength of the optical local oscillator signal LO2' can be selected from the wavelength offset of the optical local oscillator signal LO1' by a wavelength offset X (e.g., the frequency of the THF signal to be emitted and / or received by the optical local oscillator signals LO1 and LO2).

[0075] Beam splitter 104 can transmit a first amount of power from the optical local oscillator signal LO2' to UTC PD 118 as the optical local oscillator signal LO2'' via optical path 106. Beam splitter 104 can also transmit a second amount of power from the optical local oscillator signal LO2' to output terminal 108 as the optical local oscillator signal LO2 (e.g., where the second amount of power is greater than the first amount). As an example, beam splitter 104 can provide 10% of the power of the optical local oscillator signal LO2'' to UTC PD 118 as the optical local oscillator signal LO2'', and can provide 90% of the power of the optical local oscillator signal LO2'' to output terminal 108 as the optical local oscillator signal LO2.

[0076] Simultaneously, beam splitter 104 can transmit a first amount of power from the optical local oscillator signal LO1' to UTC PD 118 as the optical local oscillator signal LO1'' via optical path 114. Beam splitter 112 can transmit a second amount of power from the optical local oscillator signal LO1' to output terminal 110 as the optical local oscillator signal LO1 (e.g., where the second amount of power is greater than the first amount). As an example, beam splitter 112 can provide 10% of the power of the optical local oscillator signal LO1'' to UTC PD 118 as the optical local oscillator signal LO1'', and can provide 90% of the power of the optical local oscillator signal LO1'' to output terminal 110 as the optical local oscillator signal LO1. The optical local oscillator signals LO2'' and LO1'' can be processed by the FLL and PLL in OPLL 75 to frequency-lock and phase-lock the optical local oscillator signals LO1 and LO2.

[0077] Optical path 106 can illuminate UTC PD 118 using optical local oscillator signal LO2''. Optical path 114 can illuminate UTC PD 114 using optical local oscillator signal LO1''. Figure 8 The UTC PD 118 need not be a UTC PD, and generally can be an adjustable / programmable photodiode or a component on path 120 that converts electromagnetic energy (e.g., light or optical energy) at optical frequencies (e.g., ultraviolet frequencies, visible light frequencies, and / or infrared frequencies) into current at THF frequencies (e.g., for use with...). Figure 6 The optical local oscillator signals LO1 and LO2 are the same type of components that generate current on the antenna radiating element arm 36.

[0078] The UTC PD 118 can generate and output a photodiode signal PD_SIG on path 120 based on the optical local oscillator signals LO2'' and LO1'' received via optical paths 106 and 114. The photodiode signal PD_SIG can be based on the difference between the frequency of the optical local oscillator signal LO2'' and the frequency of the optical local oscillator signal LO1'' (e.g., ...). Figure 6 The frequency given is the frequency of the THF signal 32 / 34. Path 120 can transmit the photodiode signal PD_SIG to counter 98 in FLL loop path 130.

[0079] like Figure 8 As shown, reference oscillator 90 can generate a reference oscillator signal osc. Reference oscillator 90 can be, for example, a microelectromechanical system (MEMS) oscillator, a crystal oscillator, or any other fixed or slightly tunable stable oscillator. The reference oscillator signal osc can be generated at a fixed radio frequency, such as between approximately 5 GHz and 25 GHz. Reference oscillator 90 provides the reference oscillator signal osc to DTC 92 and counter 98 via path 94.

[0080] Counter 98 can use a reference oscillator signal osc to measure (e.g., determine, identify, generate, calculate, estimate, etc.) the frequency of the photodiode signal PD_SIG received via path 120. For example, counter 98 can use the reference oscillator signal osc to count the number of pulses in the photodiode signal PD_SIG as a reference, and then use the counted number of pulses to estimate the frequency of the photodiode signal PD_SIG. Counter 98 can also use the measured frequency of the photodiode signal PD_SIG to calculate the expected frequency difference between the optical local oscillator signals LO2'' and LO1'' (e.g., ...). Figure 6The frequency of the photodiode signal PD_SIG is compared with the expected frequency of the THF signal 32 / 34. If the difference between the frequency of the photodiode signal PD_SIG and the expected frequency exceeds a threshold, the counter 98 provides a coarse tuning control signal FLL_CTRL (e.g., a frequency error signal) to the secondary laser 102 via path 100. This FLL_CTRL coarsely adjusts the secondary laser 102 to begin outputting optical local oscillator signals LO2' at different frequencies. The coarse tuning control signal FLL_CTRL can coarsely tune the frequency of the secondary laser 102 using piezoelectric adjustment, mirror shift, etc.

[0081] Counter 98 can then continue to remeasure the photodiode signal PD_SIG and coarsely adjust the secondary laser 102 until the difference between the frequency of the photodiode signal PD_SIG and the expected frequency is less than a threshold (e.g., until the actual frequency generated by the secondary laser 102 has stabilized and is sufficiently close to the desired frequency). Once this occurs, OPLL 75 can lock (freeze) the frequency of the secondary laser 102 at the appropriate position. PLL path 128 can then finely adjust the secondary laser 102 to phase-lock the optical local oscillator signal LO2 to the optical local oscillator signal LO1.

[0082] Once the OPLL 75 has locked the frequency of the secondary laser 102 (e.g., once coarse tuning has been completed), the downsampling mixer 122 can process the photodiode signal PD_SIG. The DTC 92 can generate a DTC reference signal DTC_REF based on the reference oscillator signal osc. The DTC 92 can generate the DTC reference signal DTC_REF, for example, by programming the edges of the signal pulses to have selected timing. The DTC 92 can also set (program) the frequency, delay, duty cycle, and / or per-clock interval of the signal pulses. The DTC 92 is an open-loop system and can generate the DTC reference signal DTC_REF very quickly and without using an induction coil, thereby minimizing the chip area required to generate the DTC reference signal DTC_REF. If desired, the DTC 92 can generate a signal ramp instead of a signal pulse (e.g., the DTC reference signal DTC_REF can include either a signal pulse or a signal ramp). For example, the DTC 92 can generate the DTC reference signal DTC_REF much faster than analog components. The DTC 92 can generate a DTC reference signal DTC_REF at any desired frequency using the reference oscillator signal osc. The DTC reference signal DTC_REF can, for example, be at a frequency between 5 GHz and 25 GHz.

[0083] The downsampling mixer 122 may include a phase detector (e.g., a phase detector including digital XOR logic) and / or (e.g., a frequency detector including digital XOR logic and flip-flops). The logic in the downsampling mixer 122 (e.g., the phase detector and comparator, sometimes collectively referred to herein as a phase comparator) may compare the phase of the photodiode signal PD_SIG with the phase of the DTC reference signal DTC_REF. In implementation, the photodiode signal PD_SIG may be at a much higher frequency (e.g., 50 GHz–400 GHz) compared to the DTC reference signal DTC_REF (e.g., 5 GHz–25 GHz), making phase comparison difficult or impossible. Therefore, the downsampling mixer 122 may downsample the photodiode signal PD_SIG to generate a downsampled photodiode signal, and may compare the phase of this downsampled photodiode signal with the phase of the DTC reference signal DTC_REF (e.g., where the phase of the downsampled photodiode signal is similar to the phase of the original photodiode signal). For example, the downsampling mixer 122 can downsample the photodiode signal PD_SIG by comparing only a regularly spaced subset of samples in the photodiode signal PD_SIG (e.g., every eight photodiode signal PD_SIG samples) with, for example, a DTC reference signal DTC_REF.

[0084] The downsampling mixer 122 compares the difference between the measured phase of the photodiode signal PD_SIG (e.g., a downsampled photodiode signal) and the phase of the DTC reference signal DTC_REF with a predetermined threshold. If the difference exceeds the threshold, the downsampling mixer 122 provides a fine-tuning control signal PLL_CTRL to the secondary laser 102 via path 124. This PLL_CTRL finely tunes the secondary laser 102 to begin outputting optical local oscillator signals LO2' at different phases. The fine-tuning control signal PLL_CTRL can be, for example, an error signal indicating phase error in the optical local oscillator generated by the secondary laser 102. The loop filter 126 can filter the error signal (e.g., using a 1MHz-3MHz filter). For example, the fine-tuning control signal PLL_CTRL can finely tune the phase of the secondary laser 102 by adjusting the capacitance of the varactor diode in the secondary laser 102.

[0085] Then, the downsampling mixer 122 can continue to remeasure the photodiode signal PD_SIG and finely adjust the secondary laser 102 until the difference between the phase of the photodiode signal PD_SIG (e.g., the downsampled photodiode signal) and the phase of the DTC reference signal DTC_REF is less than a threshold (e.g., until the phase of the secondary laser 102 stabilizes at the desired phase exhibited by the DTC reference signal DTC_REF). Once this occurs, the OPLL 75 can lock (freeze) the phase of the secondary laser 102 in place.

[0086] The optical local oscillator signals LO1 and LO2 generated by the primary laser 116 and the secondary laser 102 can then be frequency-locked and phase-locked. This allows the optical local oscillator signals LO1 and LO2 to be used for timing other components in the device 10 with minimal jitter and minimal phase noise (e.g., for control). Figure 6 and Figure 7 The UTC PD 42 in the wireless circuit 24 transmits and / or receives THF signals. Using a DTC (such as DTC 92) to generate optical local oscillator signals LO1 and LO2 in this manner allows for flexibility in reference clock selection and clock signal processing. For example, DTC 92 can be used via a PLL loop for reference clock modulation, fine frequency tuning, frequency jitter processing, etc., where spurious signals generated by the DTC are filtered out by loop filter 126. Compared to comb frequency generation and / or frequency generation using MZM, OPLL 75 allows for minimal spurious frequencies in the optical domain with minimal filtering requirements.

[0087] Figure 8 The examples provided are merely illustrative. If desired, the secondary laser 102 and the primary laser 116 may share the same resonant cavity (e.g., the secondary laser 102 may utilize a longer or shorter resonant cavity portion compared to the primary laser 116 to allow for wavelength differences between the optical local oscillator signals). Sharing a common resonant cavity between the secondary laser 102 and the primary laser 116 causes them to exhibit very similar thermal effects, thus facilitating tight locking of the secondary laser 102 to the primary laser 116. Generating the optical local oscillator signals LO1 and LO2 in a closed-loop manner in this way minimizes phase noise in the optical local oscillator signals LO1 and LO2. Components of the OPLL 75 may be implemented in hardware (e.g., one or more digital logic gates, digital circuits, analog circuits, one or more processors, etc.) and / or software (e.g., using logic / computation operations performed by one or more processors).

[0088] Figure 9 for Figure 8The timing diagram shows an exemplary signal pulse in the DTC reference signal DTC_REF. Curve 132 illustrates a signal pulse that can be generated by DTC 92, and curve 134 illustrates another pulse that can be generated by DTC 92. DTC 92 can be programmed to adjust the timing, slope, and / or spacing of the leading edge 136 and / or falling edge 138 of the signal pulse. Such adjustments can be extremely precise (e.g., at the picosecond level). The frequency, delay, and / or duty cycle of the signal pulse can also be precisely programmed by DTC 92. Figure 9 The examples provided are for illustrative purposes only. Curves 132 and 134 may have other shapes. If desired, the DTC reference signal DTC_REF may include a signal ramp instead of a signal pulse.

[0089] Figure 10 For use Figure 8 The OPLL 75 generates optical local oscillator signals LO1 and LO2 (e.g., to correspond to one or more components in device 10, such as...). Figure 1 The flowchart illustrates the exemplary operations involved in the timing process of the wireless circuit 24. Figure 10 At operation 140, the secondary laser 102 and the primary laser 116 can use optical local oscillator signals LO2'' and LO1'' to begin irradiating the UTC PD 118. The UTC PD 188 can generate a photodiode signal PD_SIG based on the optical local oscillator signals LO2'' and LO1''.

[0090] At operation 142, OPLL 75 can coarsely tune the secondary laser 102 using FLL path 130. For example, at operation 144, reference oscillator 90 can begin generating a reference oscillator signal osc and can provide the reference oscillator signal osc to DTC 92 and counter 98.

[0091] In operation 146, counter 98 can use a reference oscillator signal osc as a reference to identify the frequency of the photodiode signal PD_SIG. Logic in counter 98 (e.g., comparators and / or other digital logic) can compare the identified frequency with a predetermined / expected / selected frequency of the secondary laser 102. If the identified frequency deviates excessively from the expected frequency (e.g., if the difference between the identified and expected frequencies exceeds a threshold), the process can proceed to operation 150, as shown by path 148. At operation 150, counter 98 can coarsely adjust the frequency of the secondary laser 102 using a coarse tuning control signal FLL_CTRL. The process can loop back to operation 146 via path 152 until the identified frequency is sufficiently close to the expected frequency.

[0092] When the identified frequency is sufficiently close to the expected frequency (e.g., when the difference between the identified frequency and the expected frequency is less than a threshold), the process can proceed from operation 146 to operation 156, as shown by path 154. At operation 156, OPLL75 can lock the coarse tuning of the secondary laser 102 (e.g., frequency-lock the secondary laser 102 and the optical local oscillator signal LO2'). The process can then proceed via path 158 to operation 160.

[0093] At operation 160, OPLL 75 can finely tune the secondary laser 102 using PLL path 128. For example, at operation 162, DTC 92 can generate a DTC reference signal DTC_REF using a reference oscillator signal osc. DTC 92 can generate the DTC reference signal DTC_REF at a predetermined / selected / desired phase and frequency (e.g., 5 GHz–25 GHz). DTC 92 can downsample the DTC reference signal DTC_REF to mixer 122.

[0094] In operation 164, downsampling mixer 122 downsamples the photodiode signal PD_SIG and compares the phase of the downsampled photodiode signal with the phase of the DTC reference signal DTC_REF. If the identified phase of the downsampled photodiode signal deviates excessively from the phase of the DTC reference signal DTC_REF (e.g., if the difference between the identified phase and the phase of the DTC reference signal DTC_REF exceeds a threshold), the process proceeds to operation 168, as shown by path 166. At operation 168, downsampling mixer 122 finely adjusts the phase of the secondary laser 102 using the fine-tuning control signal PLL_CTRL. The process can loop back to operation 164 via path 170 until the identified phase is sufficiently close to the phase of the DTC reference signal DTC_REF.

[0095] When the identified phase is sufficiently close to the phase of the DTC reference signal DTC_REF (e.g., when the difference between the identified phase and the phase of the DTC reference signal DTC_REF is less than a threshold), the process can proceed from operation 164 to operation 174, as shown by path 172. At operation 174, OPLL 75 can lock the fine tuning of the secondary laser 102 (e.g., the secondary laser 102 and the optical local oscillator signal LO2' can be phase-locked). The process can then proceed via path 176 to operation 178.

[0096] At operation 178, OPLL 75 may use optical local oscillator signals LO1 and LO2 to time one or more processing operations in device 10 (e.g., device 10 may perform subsequent processing operations as timed by optical local oscillator signals LO1 and LO2). For example, UTC PD 42 in device 10 may use optical local oscillator signals LO1 and LO2 generated by OPLL 75 to transmit and / or receive THF signals.

[0097] Device 10 may collect and / or use personally identifiable information. It is well known that the use of personally identifiable information should comply with privacy policies and practices generally recognized as meeting or exceeding industry or governmental requirements for protecting user privacy. Specifically, personally identifiable information data should be managed and processed to minimize the risk of unintentional or unauthorized access or use, and the nature of authorized use should be clearly explained to the user. If necessary, the optical components described herein (e.g., MZM modulators, waveguides, phase shifters, UTC PDs, etc.) may be implemented in plasmonic technology.

[0098] The above text combined Figures 1 to 10 The methods and operations described (e.g., Figure 10 The operations can be performed by components of device 10 using software, firmware, and / or hardware (e.g., dedicated circuitry or hardware). The software code used to perform these operations may be stored on a non-transitory computer-readable storage medium (e.g., a tangible computer-readable storage medium) stored on one or more components of device 10 (e.g., ...). Figure 1 The storage circuit 16). This software code may sometimes be referred to as software, data, instructions, program instructions, or code. Non-transitory computer-readable storage media may include drives, non-volatile memory such as non-volatile random access memory (NVRAM), removable flash drives or other removable media, other types of random access memory, etc. The software stored on the non-transitory computer-readable storage medium may be processed by processing circuitry on one or more components of device 10 (e.g., Figure 1 The processing circuitry (e.g., 18) performs the execution. The processing circuitry may include a microprocessor, a central processing unit (CPU), an application-specific integrated circuit (ASIC) with processing circuitry, or other processing circuitry.

[0099] According to one embodiment, an electro-optical phase-locked loop is provided, comprising: a first light source configured to emit light at a first frequency; a second light source configured to emit light at a second frequency offset from the first frequency by an offset frequency of at least 50 GHz; a feedback path communicatively coupling the output of the second light source to an input of the second light source; a digital time converter (DTC) configured to generate a reference signal; and a phase comparator disposed along the feedback path, the phase comparator being configured to adjust the second light source at least partially based on the reference signal.

[0100] According to another embodiment, the electro-optical phase-locked loop further includes: a photodiode having an output coupled to an input of the phase comparator; a first optical path communicatively coupling the output of the first light source to the photodiode; and a second optical path communicatively coupling the output of the second light source to the photodiode, the photodiode being configured to generate a photodiode signal at the offset frequency using at least some of the light emitted by the first light source at the first frequency and at least some of the light emitted by the second light source at the second frequency.

[0101] According to another embodiment, the photodiode includes a single-line carrier photodiode (UTC PD).

[0102] According to another embodiment, the electro-optical phase-locked loop includes: a first beam splitter that couples the output terminal of the first light source to the first optical path and the first output terminal of the electro-optical phase-locked loop; and a second beam splitter that couples the output terminal of the second light source to the second optical path and the second output terminal of the electro-optical phase-locked loop.

[0103] According to another embodiment, the phase comparator is configured to adjust the second light source based on a comparison of the phase of the photodiode signal with the phase of the reference signal.

[0104] According to another embodiment, the electro-optical phase-locked loop includes: a downsampling mixer including the phase comparator, the downsampling mixer being configured to downsample the photodiode signal to generate a downsampled photodiode signal, and the phase comparator being configured to adjust the second light source based on a comparison of the phase of the downsampled photodiode signal with the phase of the reference signal.

[0105] According to another embodiment, the electro-optical phase-locked loop includes: an additional feedback path communicatively coupling the output of the second light source to the input of the second light source; and a counter set along the additional feedback path, the counter being configured to identify the offset frequency based on the photodiode signal and being configured to adjust the second frequency based at least on the identified offset frequency.

[0106] According to another embodiment, the electro-optical phase-locked loop includes: a reference oscillator configured to generate a reference oscillator signal, a DTC configured to generate a reference signal based on the reference oscillator signal, and a counter configured to estimate the offset frequency based on the photodiode signal and the reference oscillator signal.

[0107] According to another implementation, the reference oscillator signal is at a frequency between 5 GHz and 25 GHz.

[0108] According to another embodiment, the electro-optical phase-locked loop includes: a reference oscillator configured to generate a reference oscillator signal, the DTC configured to generate a reference signal based on the reference oscillator signal; an additional feedback path communicatively coupling the output of the second light source to the input of the second light source; and a counter set along the additional feedback path, wherein the counter is configured to identify the offset frequency at least partially based on the reference oscillator signal and is configured to adjust the second frequency at least based on the identified offset frequency.

[0109] According to one embodiment, a method for operating an electro-optical phase-locked loop is provided, the method comprising: emitting a first optical local oscillator (LO) signal at a first frequency using a first laser; emitting a second optical LO signal at a second frequency using a second laser, the second frequency being offset from the first frequency by a frequency greater than 50 GHz; coarsely tuning the second optical LO signal emitted by the second laser using a frequency-locked loop (FLL) path communicatively coupled between the output and input of the second laser until the second frequency is locked; and once the second frequency is locked, finely tuning the second optical LO signal emitted by the second laser using a phase-locked loop (PLL) path communicatively coupled between the output and input of the second laser until the second optical LO signal is phase-locked with the first optical LO signal.

[0110] According to another embodiment, the method includes: transmitting the first optical LO signal and the second optical LO signal to a photodiode, the photodiode using the first optical LO signal and the second optical LO signal to transmit a wireless signal at the offset frequency through an antenna radiating element.

[0111] According to another embodiment, the method includes: using a photodiode disposed along the FLL path and the PLL path, and using at least some of the first optical LO signals and at least some of the second optical LO signals to generate a photodiode signal at the offset frequency.

[0112] According to another embodiment, the method includes: downsampling the photodiode signal to generate a downsampled photodiode signal using a downsampling mixer disposed along the PLL path; finely tuning the second optical LO signal includes: adjusting the phase of the second optical LO signal using the downsampling mixer, at least based on the phase of the downsampled photodiode signal.

[0113] According to another embodiment, the method includes: generating a reference signal using a digital-to-analog converter (DTC); finely tuning the second optical LO signal includes: adjusting the phase of the second optical LO based on a comparison of the phase of the downsampled photodiode signal with the phase of the reference signal using the downsampled mixer.

[0114] According to another embodiment, the method includes: using a counter set along the FLL path to identify the offset frequency using the photodiode signal, and coarsely tuning the second optical LO signal includes: adjusting the second frequency based at least on the identified offset frequency.

[0115] According to one embodiment, an electronic device is provided, comprising: an antenna radiating element; a photodiode coupled to the antenna radiating element and configured to transmit a wireless signal at a frequency greater than 100 GHz using the antenna radiating element, a first optical local oscillator (LO) signal, and a second optical LO signal; and an optical component configured to generate the first optical LO signal and the second optical LO signal, the optical component including a first laser configured to emit the first optical LO signal, a second laser configured to emit the second optical LO signal, a photodiode configured to generate a photodiode signal based on the first optical LO signal and the second optical LO signal, and a downsampling mixer configured to generate a downsampled photodiode signal based on the photodiode signal and configured to tune the second laser at least partially based on the phase of the downsampled photodiode signal.

[0116] According to another embodiment, the electronic device includes: a counter configured to identify the frequency of the photodiode signal and configured to tune the second laser based at least in part on the identified frequency of the photodiode signal.

[0117] According to another embodiment, the first laser includes a first portion of a resonant cavity, and the second laser includes a second portion of the resonant cavity that is longer than the first portion.

[0118] According to another embodiment, the photodiode includes a single-line carrier photodiode (UTC PD).

[0119] The foregoing description is merely illustrative and various modifications can be made to the described implementation scheme. The described implementation scheme can be implemented independently or in any combination.

Claims

1. An electro-optical phase-locked loop, comprising: A first light source, configured to emit light at a first frequency; A second light source is configured to emit light at a second frequency, the second frequency being offset from the first frequency by at least 50 GHz. A first feedback path communicatively couples the output of the second light source to the input of the second light source, and the first feedback path is configured to coarsely tune the light emitted by the second light source. A second feedback path communicatively couples the output of the second light source to the input of the second light source, and the second feedback path is configured to finely tune the light emitted by the second light source. A digital time converter (DTC) configured to generate a reference signal; as well as A phase comparator disposed along the second feedback path, wherein the phase comparator is configured to adjust the second light source at least in part based on the reference signal.

2. The electro-optical phase-locked loop according to claim 1 further comprises: A photodiode having an output terminal coupled to the input terminal of the phase comparator; A first optical path, wherein the output of the first light source is communicatively coupled to the photodiode; as well as A second optical path communicatively couples the output of the second light source to the photodiode, wherein the photodiode is configured to generate a photodiode signal at the offset frequency using at least some of the light emitted by the first light source at the first frequency and at least some of the light emitted by the second light source at the second frequency.

3. The electro-optical phase-locked loop according to claim 2, wherein the photodiode comprises a single-line carrier photodiode (UTC PD).

4. The electro-optical phase-locked loop according to claim 2 further comprises: The first beam splitter couples the output terminal of the first light source to the first optical path and the first output terminal of the electro-optical phase-locked loop. as well as The second beam splitter couples the output terminal of the second light source to the second optical path and the second output terminal of the electro-optical phase-locked loop.

5. The electro-optical phase-locked loop of claim 2, wherein the phase comparator is configured to adjust the second light source based on a comparison of the phase of the photodiode signal with the phase of the reference signal.

6. The electro-optical phase-locked loop according to claim 5 further comprises: A downsampling mixer, the downsampling mixer including the phase comparator, wherein the downsampling mixer is configured to downsample the photodiode signal to generate a downsampled photodiode signal, and the phase comparator is configured to adjust the second light source based on a comparison of the phase of the downsampled photodiode signal with the phase of the reference signal.

7. The electro-optical phase-locked loop according to claim 2 further comprises: A counter, which is set along the first feedback path, wherein the counter is configured to identify the offset frequency based on the photodiode signal and is configured to adjust the second frequency based at least on the identified offset frequency.

8. The electro-optical phase-locked loop according to claim 7, further comprising: A reference oscillator is configured to generate a reference oscillator signal, wherein the DTC is configured to generate the reference signal based on the reference oscillator signal, and the counter is configured to estimate the offset frequency based on the photodiode signal and the reference oscillator signal.

9. The electro-optical phase-locked loop of claim 8, wherein the reference oscillator signal is at a frequency between 5 GHz and 25 GHz.

10. The electro-optical phase-locked loop according to claim 1, further comprising: A reference oscillator configured to generate a reference oscillator signal, wherein the DTC is configured to generate the reference signal based on the reference oscillator signal; as well as A counter, which is set along the first feedback path, wherein the counter is configured to identify the offset frequency at least in part based on the reference oscillator signal and is configured to adjust the second frequency at least based on the identified offset frequency.

11. A method for operating an electro-optical phase-locked loop, the method comprising: Using a first laser, a first optical local oscillator (LO) signal at a first frequency is emitted; Using a second laser, a second optical LO signal at a second frequency is emitted, the second frequency being offset from the first frequency by a frequency greater than 50 GHz. The second optical LO signal emitted by the second laser is roughly tuned by using a frequency-locked loop (FLL) path that is communicatively coupled between the output and input terminals of the second laser until the second frequency is locked. as well as Once the second frequency is locked, the second optical LO signal emitted by the second laser is finely tuned using a phase-locked loop (PLL) path that is communicatively coupled between the output and input terminals of the second laser, until the second optical LO signal is phase-locked with the first optical LO signal.

12. The method of claim 11, further comprising: The first optical LO signal and the second optical LO signal are transmitted to a photodiode, which uses the first optical LO signal and the second optical LO signal to transmit a wireless signal at the offset frequency through an antenna radiating element.

13. The method of claim 11, further comprising: Using photodiodes arranged along the FLL path and the PLL path, a photodiode signal at the offset frequency is generated using at least some of the first optical LO signals and at least some of the second optical LO signals.

14. The method of claim 13, further comprising: The photodiode signal is downsampled using a downsampling mixer arranged along the PLL path to generate a downsampled photodiode signal, wherein fine tuning of the second optical LO signal includes adjusting the phase of the second optical LO signal using the downsampling mixer, at least based on the phase of the downsampled photodiode signal.

15. The method of claim 14, further comprising: A reference signal is generated using a digital-to-analog converter (DTC), wherein fine tuning of the second optical LO signal includes adjusting the phase of the second optical LO based on a comparison of the phase of the downsampled photodiode signal with the phase of the reference signal using the downsampled mixer.

16. The method of claim 13, further comprising: Using a counter positioned along the FLL path, the offset frequency is identified using the photodiode signal, wherein coarsely tuning the second optical LO signal includes adjusting the second frequency at least based on the identified offset frequency.

17. An electronic device comprising: Antenna radiating elements; A photodiode coupled to the antenna radiating element and configured to transmit wireless signals at frequencies greater than 100 GHz using the antenna radiating element, a first optical local oscillator (LO) signal, and a second optical LO signal; as well as Optical components configured to generate the first optical LO signal and the second optical LO signal, the optical components including A first laser, configured to emit the first optical LO signal. A second laser, configured to emit the second optical LO signal. A photodiode configured to generate a photodiode signal based on the first optical LO signal and the second optical LO signal. A first feedback path communicatively couples the output of the second laser to its input, and this first feedback path is configured to coarsely tune the second optical LO signal. A second feedback path communicatively couples the output of the second laser to the input of the second laser. This second feedback path is configured to finely tune the second optical LO signal. A downsampling mixer configured to generate a downsampled photodiode signal based on the photodiode signal and configured to at least partially tune the second laser based on the phase of the downsampled photodiode signal.

18. The electronic device of claim 17, further comprising: A counter configured to identify the frequency of the photodiode signal and configured to tune the second laser at least in part based on the identified frequency of the photodiode signal.

19. The electronic device of claim 17, wherein the first laser includes a first portion of a resonant cavity, and the second laser includes a second portion of the resonant cavity that is longer than the first portion.

20. The electronic device of claim 17, wherein the photodiode comprises a single-line carrier photodiode (UTC PD).

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