Low phase noise high frequency signal generation apparatus and method based on a key-on optical reference source

Abstract

This application provides a low-phase-noise, high-frequency signal generation device and method based on a keyed optical reference source. The device includes: a laser control module configured to emit a first laser and a second laser; a first optical filter configured to combine the first and second lasers; a second optical filter configured to split the combined laser beam into a first split laser beam and a second split laser beam; a photoelectric detection module configured to generate a difference frequency signal based on the first combined laser beam and determine the light intensity values ​​of the first and second split laser beams; and a control module configured to acquire the target output frequencies of the first and second lasers and drive the laser control module to operate with a target driving voltage value and the required laser phase. This addresses the problem that current PDH-based locking methods struggle to achieve automated startup and long-term stable operation over a wide temperature range without human intervention.

Description

Technical Field

[0001] This application relates to the field of optical equipment technology, and in particular to a low-phase-noise high-frequency signal generation device and method based on a key-type optical reference source. Background Technology

[0002] Low-phase-noise microwave and terahertz wave signals have crucial application value in fields such as communication, radar, navigation, and precision measurement. Opto-electronic oscillators (OEOs) convert optical frequency signals into microwave or terahertz wave signals through photoelectric conversion, and utilize long optical fibers or high-Q resonant cavities for energy storage and mode selection to achieve extremely low phase noise. However, such systems are typically composed of discrete optical and electronic components, resulting in large size, complex structure, and susceptibility to environmental interference, making it difficult to meet the current urgent need for system integration and chip-based architecture.

[0003] In recent years, photonic microwave and terahertz wave generation technologies based on high-Q optical microcavities (such as whispering corridor mode microcavities) have attracted widespread attention. This technology simultaneously locks two phase-coherent laser beams to different resonant modes of the same microcavity. The difference frequency signal is then directly detected by a high-speed photodetector, yielding a low-phase-noise microwave or terahertz wave signal with a frequency equal to the difference frequency between the two resonant modes. This eliminates the need for long optical fibers or high-Q resonant cavities in traditional OEO systems, demonstrating significant advantages in reducing system size and complexity. For laser locking, the Pound-Drever-Hall (PDH) technique is typically used. This technique applies phase modulation to the laser and uses a feedback loop to stably lock the laser frequency to the microcavity resonant peak.

[0004] However, PDH locking technology requires additional phase modulators and complex feedback circuits, which increases the complexity of the system's optical structure and power consumption, hindering the high integration of the system. Furthermore, the resonant frequency of the optical microcavity is extremely sensitive to ambient temperature fluctuations, and temperature changes can cause the resonant frequency to drift. This makes it difficult for PDH-based locking methods to achieve automated startup and long-term stable operation over a wide temperature range without human intervention, thus hindering the practical application of this technology. Summary of the Invention

[0005] This application provides a low-phase-noise high-frequency signal generation device and method based on a key-type optical reference source, in order to solve the technical problem that the current PDH-based locking method is difficult to achieve automatic start-up and long-term stable operation over a wide temperature range without human intervention.

[0006] The first aspect of this application provides a low-phase-noise, high-frequency signal generation device based on a key-type optical reference source, comprising: The system comprises a laser control module, a first optical filter, a high-quality factor optical microcavity, a photoelectric detection module, a second optical filter, and a control module; the control module is electrically connected to the laser control module and the photoelectric detection module. The laser control module is configured as follows: The first laser and the second laser are emitted to the first optical filter; The first optical filter is configured as follows: The first laser and the second laser are combined and then input into the high-quality factor optical microcavity; the high-quality factor optical microcavity transmits the combined laser beam into a first combined laser beam and a second combined laser beam; the first combined laser beam is input into the photoelectric detection module, and the second combined laser beam is input into the second optical filter; The second optical filter is configured as follows: The second combined laser beam is split into a first split laser beam and a second split laser beam, and then input into the photoelectric detection module respectively; The photoelectric detection module is configured as follows: Based on the first combined laser beam, a difference frequency signal is generated; the difference frequency signal is a low phase noise microwave or terahertz wave signal. Determine the light intensity values ​​of the first and second split laser beams; The control module is configured as follows: Obtain the target output frequencies of the first laser and the second laser; Based on the target output frequency, the required resonant frequencies for locking the first laser and the second laser to the high-quality factor optical microcavity, the required laser phases for the first laser and the second laser, and the required driving voltage value for the laser control module are determined. Based on the light intensity value, the required driving voltage value, and the required resonant frequency, determine the target driving voltage value; The laser control module is driven to operate at the target driving voltage value and the desired laser phase.

[0007] In some embodiments, the laser control module includes: First laser control component and second laser control component; The first laser control component includes: A first distributed feedback laser and a first silicon-based polarization controller; the first distributed feedback laser is used to emit a first laser beam to the first silicon-based polarization controller; the first silicon-based polarization controller is used to adjust the laser phase of the first laser beam and input the adjusted first laser beam to the first optical filter; The second laser control component includes: A second distributed feedback laser and a second silicon-based polarization controller; the second distributed feedback laser is used to emit a second laser to the second silicon-based polarization controller; the second silicon-based polarization controller is used to adjust the laser phase of the second laser and input the adjusted second laser to the first optical filter.

[0008] In some embodiments, the control module is further configured to: Drive the first distributed feedback laser and the second distributed feedback laser to operate at a first required driving voltage value, so that the laser frequencies of the first laser and the second laser are within the required resonant frequency range; The maximum light intensity values ​​of the first and second beam splitters are obtained when the laser frequencies of the first and second lasers are within the required resonant frequency range. The target driving voltage value corresponding to the maximum light intensity value is determined, and the first distributed feedback laser and the second distributed feedback laser are driven with the target driving voltage value; and the first silicon-based polarization controller and the second silicon-based polarization controller are driven to operate with the required laser phase.

[0009] In some embodiments, the photoelectric detection module includes: a first photodetector, a second photodetector, and a third photodetector; A first photodetector is used to receive the first split laser beam input from the second optical filter and determine the light intensity value of the first split laser beam, which is then sent to the control module. The second photodetector is used to receive the second split laser beam input from the second optical filter and determine the light intensity value of the second split laser beam, which is then sent to the control module. The third photodetector is used to receive the first combined laser beam input from the high-quality factor optical microcavity, and based on the first combined laser beam, generates a difference frequency signal and sends it to the control module.

[0010] In some embodiments, the apparatus further includes: A temperature control module, electrically connected to the control module; the temperature control module includes: a semiconductor cooling chip and a thermistor monitoring unit; The semiconductor cooling chip is used to regulate the operating temperature within the device; The thermistor monitoring unit is used to acquire the temperature value inside the device.

[0011] In some embodiments, the control module is further configured to: Based on the target output frequency, determine the required operating temperature value of the device and the second required drive voltage value of the temperature control module; The temperature control module is driven to operate at the second required drive voltage value, so that the temperature value inside the device is within the required operating temperature range.

[0012] In some embodiments, the temperature control module is configured to: Determine whether the temperature value inside the device is within the required operating temperature range; If not, the semiconductor cooling chip is driven to increase power or stop operating, so that the temperature value inside the device is restored to the required operating temperature range.

[0013] In some embodiments, the control module is further configured to: Determine whether the first and second lasers have drifted; If so, then the steps of determining the required resonant frequencies of the first and second lasers locked to the high-quality factor optical microcavity, the required laser phases of the first and second lasers, and the required driving voltage value of the laser control module based on the target output frequency are re-executed.

[0014] In some embodiments, the high-quality factor optical microcavity is any one of a microring resonator, a microdisk cavity, a whispering corridor mode optical microcavity, or a photonic crystal microcavity.

[0015] The second aspect of this application provides a method for generating low-phase-noise high-frequency signals based on a keyed optical reference source, applied to the low-phase-noise high-frequency signal generation apparatus based on a keyed optical reference source described in any one of the first aspects above, comprising: The first and second lasers are emitted to the first optical filter; The first laser and the second laser are combined and then input into a high-quality factor optical microcavity; the high-quality factor optical microcavity transmits the combined laser beam into a first combined laser beam and a second combined laser beam; the first combined laser beam is input into a photoelectric detection module, and the second combined laser beam is input into a second optical filter; The second combined laser beam is split into a first split laser beam and a second split laser beam, and then input into the photoelectric detection module respectively; Based on the first combined laser beam, a difference frequency signal is generated; the difference frequency signal is a low phase noise microwave or terahertz wave signal. Determine the light intensity values ​​of the first and second split laser beams; Obtain the target output frequencies of the first laser and the second laser; Based on the target output frequency, the required resonant frequencies for locking the first laser and the second laser to the high-quality factor optical microcavity, the required laser phases for the first laser and the second laser, and the required driving voltage value for the laser control module are determined. Based on the light intensity value, the required driving voltage value, and the required resonant frequency, determine the target driving voltage value; The laser control module is driven to operate at the target driving voltage value and the desired laser phase.

[0016] This application provides a low-phase-noise, high-frequency signal generation device and method based on a keyed optical reference source. The device includes: a laser control module, a first optical filter, a high-quality-factor optical microcavity, a photodetector module, a second optical filter, and a control module. The control module is electrically connected to the laser control module and the photodetector module. The laser control module is configured to emit a first laser and a second laser to the first optical filter. The first optical filter is configured to combine the first laser and the second laser and input them into the high-quality-factor optical microcavity. The high-quality-factor optical microcavity transmits the combined laser beam as a first combined laser and a second combined laser. The first combined laser is input to the photodetector module, and the second combined laser is input to the second optical filter. The second optical filter is configured to split the second combined laser beam into a first split laser and a second split laser, and then... The input is sent to the photoelectric detection module; the photoelectric detection module is configured to: generate a difference frequency signal based on the first combined laser beam; the difference frequency signal is a low phase noise microwave or terahertz wave signal; determine the light intensity values ​​of the first split laser beam and the second split laser beam; the control module is configured to: acquire the target output frequency of the first laser beam and the second laser beam; based on the target output frequency, determine the required resonant frequency for locking the first laser beam and the second laser beam to the high quality factor optical microcavity, the required laser phase of the first laser beam and the second laser beam, and the required driving voltage value of the laser control module; based on the light intensity value, the required driving voltage value, and the required resonant frequency, determine the target driving voltage value; drive the laser control module to operate at the target driving voltage value and the required laser phase to generate a continuously adjustable low phase noise frequency signal with excellent common-mode noise suppression capability. Attached Figure Description

[0017] To more clearly illustrate the technical solution of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1This is a schematic diagram of the low phase noise high frequency signal generation device based on a keyed optical reference source in this application. Figure 2 This is a diagram showing the connection relationships of the components in the low phase noise high frequency signal generation device based on a key-type optical reference source in this application.

[0019] Explanation of reference numerals in the attached figures: 1-Laser control module; 11-First laser control component; 111-First distributed feedback laser; 112-First silicon-based polarization controller; 12-Second laser control component; 121-Second distributed feedback laser; 122-Second silicon-based polarization controller; 2-First optical filter; 3-High-quality factor optical microcavity; 4-Photodetector module; 41-First photodetector; 42-Second photodetector; 43-Third photodetector; 5-Second optical filter; 6-Control module; 7-Temperature control module; 71-Semiconductor cooling chip; 72-Thermistor monitoring unit. Detailed Implementation

[0020] To enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this application.

[0021] Because in some technologies, the PDH-based locking method is difficult to achieve automated startup and long-term stable operation over a wide temperature range without human intervention, this application provides a low-phase-noise high-frequency signal generation device and method based on a key-type optical reference source to solve this technical problem. The low-phase-noise high-frequency signal generation device and method based on a key-type optical reference source are described below: like Figure 1 The diagram shown is a schematic representation of the low phase noise high frequency signal generation device based on a keyed optical reference source in this application.

[0022] The first aspect of this application provides a low-phase-noise, high-frequency signal generation device based on a key-type optical reference source, comprising: The system comprises a laser control module 1, a first optical filter 2, a high-quality factor optical microcavity 3, a photoelectric detection module 4, a second optical filter 5, and a control module 6; the control module 6 is electrically connected to the laser control module 1 and the photoelectric detection module 4. The optical filter is a wavelength division multiplexer, exhibiting high transmission for the first laser beam and high reflection for the second laser beam. The control module 6 is one of a field-programmable gate array, a microcontroller, or an application-specific integrated circuit.

[0023] like Figure 2 The diagram shown is a connection diagram of the components in the low phase noise high frequency signal generation device based on a keyed optical reference source in this application.

[0024] The laser control module 1 is configured as follows: The first laser and the second laser are emitted to the first optical filter 2.

[0025] The laser control module 1 includes: a first laser control component 11 and a second laser control component 12.

[0026] The first laser control component 11 includes: A first distributed feedback laser 111 and a first silicon-based polarization controller 112; the first distributed feedback laser 111 is used to emit a first laser to the first silicon-based polarization controller 112; the first silicon-based polarization controller 112 is used to adjust the laser phase of the first laser and input the adjusted first laser to the first optical filter 2.

[0027] The second laser control component 12 includes: A second distributed feedback laser 121 and a second silicon-based polarization controller 122; the second distributed feedback laser 121 is used to emit a second laser to the second silicon-based polarization controller 122; the second silicon-based polarization controller 122 is used to adjust the laser phase of the second laser and input the adjusted second laser to the first optical filter 2.

[0028] Among them, the first distributed feedback laser 111 and the second distributed feedback laser 121 are frequency-tunable lasers.

[0029] The first optical filter 2 is configured as follows: The first laser and the second laser are combined and input into the high-quality factor optical microcavity 3; the high-quality factor optical microcavity 3 transmits the combined laser beam into a first combined laser beam and a second combined laser beam; the first combined laser beam is input into the photoelectric detection module 4, and the second combined laser beam is input into the second optical filter 5.

[0030] For example, the Q-factor (quality factor) of the high-quality optical microcavity 3 can be as high as 10. 6 Even 10 11 The above features extremely low energy attenuation. The high-quality factor optical microcavity 3 can be any one of a microring resonator, a microdisk cavity, a whispering corridor mode optical microcavity, or a photonic crystal microcavity.

[0031] The second optical filter 5 is configured as follows: The second combined laser beam is split into a first split laser beam and a second split laser beam, and then input into the photoelectric detection module 4 respectively.

[0032] The photoelectric detection module 4 is configured as follows: Based on the first combined laser beam, a difference frequency signal is generated; the difference frequency signal is a low phase noise microwave or terahertz wave signal.

[0033] Determine the light intensity values ​​of the first and second split laser beams.

[0034] For example, the photoelectric detection module 4 includes: a first photodetector 41, a second photodetector 42, and a third photodetector 43; the first photodetector 41 is used to receive the first split laser beam input from the second optical filter 5 and determine the light intensity value of the first split laser beam, which is then sent to the control module 6; the second photodetector 42 is used to receive the second split laser beam input from the second optical filter 5 and determine the light intensity value of the second split laser beam, which is then sent to the control module 6; the third photodetector 43 is used to receive the first combined laser beam input from the high-quality factor optical microcavity 3 and, based on the first combined laser beam, generate a difference frequency signal, which is then sent to the control module 6.

[0035] The control module 6 is configured as follows: Obtain the target output frequencies of the first laser and the second laser.

[0036] Based on the target output frequency, the required resonant frequencies for locking the first laser and the second laser to the high-quality factor optical microcavity 3, the required laser phases for the first laser and the second laser, and the required driving voltage value for the laser control module 1 are determined.

[0037] Based on the light intensity value, the required driving voltage value, and the required resonant frequency, the target driving voltage value is determined.

[0038] Specifically, the control module 6 is further configured as follows: The first distributed feedback laser 111 and the second distributed feedback laser 121 are driven to operate at a first required driving voltage value, so that the laser frequencies of the first laser and the second laser are within the required resonant frequency range.

[0039] The maximum light intensity values ​​of the first and second split laser beams are obtained when the laser frequencies of the first and second laser beams are within the required resonant frequency range.

[0040] The target driving voltage value corresponding to the maximum light intensity value is determined, and the first distributed feedback laser 111 and the second distributed feedback laser 121 are driven with the target driving voltage value; and the first silicon-based polarization controller 112 and the second silicon-based polarization controller 122 are driven to operate with the required laser phase.

[0041] The laser control module 1 is driven to operate at the target driving voltage value and the required laser phase.

[0042] The control module 6 is also configured to: Determine whether the first laser and the second laser have drifted; if so, re-execute the steps of determining the required resonant frequency for locking the first laser and the second laser to the high-quality factor optical microcavity 3, the required laser phase for the first laser and the second laser, and the required driving voltage value for the laser control module 1 based on the target output frequency.

[0043] For example, the control module 6 includes a human-machine interaction function for interacting with the outside world and obtaining the target output frequencies of the first laser and the second laser; a frequency selection and calculation function for calculating various parameters required under given conditions, including the operating temperature, the laser phase required for the two lasers, and further specific voltages required to be supplied to various devices, including the first distributed feedback laser 111 and the second distributed feedback laser 121, the first silicon-based polarization controller 112 and the second silicon-based polarization controller 122, the semiconductor cooling chip 71, etc.; and a data processing and decision-making function for receiving data from the human-machine interaction module, the temperature control module 7, and the photoelectric detection module 4, and determining the operating status through logical operations and making further decisions. For example, the system determines whether the laser has been successfully locked onto the high-quality factor optical microcavity 3, whether the laser frequency has drifted after prolonged operation, and whether the temperature has changed. Further decisions are then made regarding whether heating or cooling is needed, whether the laser current and voltage need adjustment, or even frequency scanning to retest the resonant frequency of the optical cavity and correct data in the frequency selection and calculation functions. The motorized control function provides specific voltages and currents to various devices under the control of data processing and decision-making functions, including the first distributed feedback laser 111 and the second distributed feedback laser 121, the first silicon-based polarization controller 112 and the second silicon-based polarization controller 122, and the semiconductor cooling chip 71. Through the cooperation of these functions, a key-based start-up is ultimately achieved, maintaining the stability of each module, adapting to different optical cavities, and maintaining stable output.

[0044] This application provides a low-phase-noise high-frequency signal generation device based on a key-activated optical reference source, comprising a control module 6, a laser modulation module 1, a first optical filter 2, a second optical filter 5, a high-quality factor optical microcavity 3, a photoelectric detection module 4, and a temperature control module 7. The control module 6 includes functions such as human-machine interaction, calculation of required parameters, data reception and processing, and electric control. The laser modulation module 1 generates lasers with specific frequencies and phases, the temperature control module 7 establishes and maintains the operating temperature accordingly, and the photoelectric detection module 4 directly detects the frequencies of the two laser beams through a photodetector and outputs and monitors the light intensity. All three are implemented under the control of the control module 6, and various data during the operation are also fed back to the control module 6. This device achieves key-activated operation through automated control, achieves extremely high common-mode rejection and extremely low phase noise by injecting two laser beams into the high-quality factor optical microcavity 3, simplifies the locking circuit by utilizing self-injection locking and a high-Q optical microcavity, and possesses advantages such as compact structure, continuously adjustable frequency, strong common-mode noise suppression capability, low phase noise, and long-term stable maintenance, providing an efficient and reliable solution for integrated low-phase-noise microwave photonic signal sources.

[0045] For example, the device further includes: Temperature control module 7 is electrically connected to control module 6; temperature control module 7 includes: semiconductor cooling chip 71 and thermistor monitoring unit 72.

[0046] The semiconductor cooling chip 71 is used to regulate the operating temperature inside the device; the thermistor monitoring unit 72 is used to acquire the temperature value inside the device.

[0047] The control module 6 is also configured to: Based on the target output frequency, the required operating temperature value of the device and the second required driving voltage value of the temperature control module 7 are determined; the temperature control module 7 is driven to operate at the second required driving voltage value, so that the temperature value inside the device is within the required operating temperature range. The control module 6 is configured to keep the temperature value inside the device always within the required operating temperature range.

[0048] The temperature control module 7 is configured as follows: Determine whether the temperature value inside the device is within the required operating temperature range; if not, drive the semiconductor cooling chip 71 to increase power or stop operation so that the temperature value inside the device returns to the required operating temperature range.

[0049] This application provides a low-phase-noise, high-frequency signal generation device based on a key-type optical reference source, the workflow of which is as follows: The control module 6 calculates the specific resonant frequency and required operating temperature for locking the two laser beams to the high-quality factor optical microcavity 3 based on the user-defined target frequency. Upon startup, the temperature of the high-quality factor optical microcavity 3 and the overall device is first stabilized at the calculated value using the semiconductor cooler 71. Then, the control module 6 scans the drive voltages of the two lasers respectively, causing their output laser frequencies to scan near the target resonant frequency. When the laser frequency matches a certain resonant mode of the high-quality factor optical microcavity 3, due to the resonance enhancement effect, the light coupled back to the laser from the high-quality factor optical microcavity 3 along the original optical path will also be enhanced, forming a self-injection locking phenomenon. This phenomenon significantly changes the output light intensity of the laser. Finally, this light intensity jump is detected by the first photodetector 71 and the second photodetector 72. Based on this, the control module 6 determines that the locking is successful and stops scanning, locking the laser at that operating point (target drive voltage value).

[0050] Two laser beams are matched with two different resonant modes of a high-quality-factor optical microcavity 3. They are transmitted together within the high-quality-factor optical microcavity 3 and output from the output terminal. A portion of the combined beam illuminates a third photodetector 43, which directly detects the frequencies of the two lasers and calculates their difference, generating a signal with a frequency equal to the difference between the two laser frequencies. Since the two laser beams share the same high-quality-factor optical microcavity 3 and the environment, the common-mode noise, such as ambient temperature fluctuations and mechanical vibrations, has almost the same effect on their resonant frequencies. This effect is greatly canceled out during the frequency difference process, exhibiting extremely strong common-mode noise suppression capability, thereby generating a microwave signal with extremely low phase noise. The device continuously monitors the thermistor monitoring unit 72 and fine-tunes the working state of the semiconductor cooling chip 71 and the heating resistance wire in real time based on the calculated real-time temperature data to achieve long-term maintenance and stability of the operating temperature. The device continuously monitors the light intensity of the two photodetectors (first photodetector 41 and second photodetector 42) and fine-tunes the laser parameters in real time based on the changes in light intensity to prevent frequency drift caused by long-term self-injection locking, thus achieving long-term stable self-locking maintenance.

[0051] In special cases, such as when using a high-quality factor optical microcavity 3 with unknown data, if the resonant frequency changes, this device can also perform a frequency scan to detect the various resonant frequencies of the high-quality factor optical microcavity within the selectable operating temperature range and update the database in the control module 6. If the database is incomplete, the resonant frequency at a specific temperature can be calculated using theoretical formulas based on other relevant data, and the laser frequency scan range during resonant mode matching can be expanded to ensure successful self-injection and subsequent steps.

[0052] This application provides a low-phase-noise high-frequency signal generation device based on a key-type optical reference source, which has the following embodiments: Example 1: The device includes: a first distributed feedback laser 111, a first silicon-based polarization controller 112, a second distributed feedback laser 113; a second silicon-based polarization controller 114, a semiconductor cooling chip 71 and a thermistor monitoring unit 72, a first optical filter 2, a high-quality factor optical microcavity 3, a second optical filter 5, a first photodetector 41, a second photodetector 42, a third photodetector 43, and a control module 6.

[0053] Preferably, the laser is a semiconductor laser tunable in the C-band (1528nm to 1565nm). The silicon-based polarization controller is a silicon-based phase shifter based on carrier dispersion. The semiconductor cooler is a Peltier cooler, which, together with a negative temperature coefficient thermistor, forms a high-precision temperature control loop. The optical filter is a wavelength division multiplexer (WDM) with a steep filtering edge. The quality factor (Q value) of the high-quality factor optical microcavity 3 is greater than 10. 6 The control module 6 integrates human-computer interaction, frequency selection and calculation, data acquisition and decision-making, and electric control functions. It can receive information from external human-computer interaction, thermistor monitoring unit 72, first photodetector 41, second photodetector 42, and third photodetector 43, and can control the states of the first distributed feedback laser 111, the first silicon-based polarization controller 112, the second distributed feedback laser 113, the second silicon-based polarization controller 114, and the semiconductor cooling chip 71.

[0054] The device's workflow is as follows: First, the user inputs the desired output frequency into the control module 6. The frequency selection and calculation function of the control module 6 will calculate the wavelengths of the high-quality factor optical microcavity 3 at the required operating temperature and the two target resonant modes, and calculate the theoretically required initial phase settings for the two silicon-based polarization controllers.

[0055] Next, the control module 6 controls the thermoelectric cooler 71 to establish the device temperature at the operating temperature, and adjusts the operating state of the thermoelectric cooler 71 to maintain temperature stability by monitoring the thermistor monitoring unit 72. Then, the phase bias of the silicon-based polarization controller is set. Subsequently, the control module 6 scans the laser's driving voltage within a small range near the expected required voltage, increasing and then decreasing again, so that their output wavelengths sweep across the target resonant wavelength. During the scanning process, the first photodetector 41 and the second photodetector 42 monitor the light intensity of their respective optical paths in real time. When the laser wavelength sweeps into the microcavity resonant mode, the light intensity will produce a step jump or enhancement. The control module 6 records the driving parameters at this time and locks the laser at the operating point with the highest output light intensity, completing self-injection locking.

[0056] After the two locked laser beams resonate within the high-quality factor optical microcavity 3, a portion is combined through the other port of the second optical filter 5 and output to the first photodetector 41 and the second photodetector 42. A portion of the combined beam directly illuminates the third photodetector 43, which directly detects the frequencies of the two lasers and outputs a low-phase-noise signal. Subsequently, the stabilization module begins operation, continuously monitoring the light intensity of the first photodetector 41 and the second photodetector 42. If the light intensity decreases due to frequency drift caused by prolonged self-injection, the voltage of the corresponding laser is fine-tuned to compensate, restoring the light intensity to its maximum and ensuring long-term system stability. Simultaneously, the module checks and confirms that the temperature and phase offset remain in the correct operating state.

[0057] Example 2: The device's workflow is as follows: System initialization: Receive the target frequency input by the user.

[0058] Calculate the target resonant wavelength and set temperature: Based on the built-in microcavity thermo-optic coefficient and dispersion model, the control module 6 calculates the resonant wavelength and optimal operating temperature required to make the frequency difference between the two laser beams equal to the target microwave frequency.

[0059] Temperature establishment and maintenance: The internal temperature of the device is heated or cooled to the optimal operating temperature through a closed-loop circuit composed of semiconductor cooling chip 71 and thermistor monitoring unit 72, and then switched to temperature maintenance mode.

[0060] Laser scanning and lock-on identification: The current of the first distributed feedback laser 111 and the second distributed feedback laser 121 is controlled so that their wavelengths continuously scan from low to high and then from high to low near their respective target resonant wavelengths. The light intensity signals of the first photodetector 41 and the second photodetector 42 are acquired simultaneously, and the abrupt light intensity jump point caused by resonance is identified by the slope or threshold algorithm, and the laser driving parameters at this time are recorded.

[0061] Setting the lock point: Set the driving parameters of laser 1 and laser 2 to the parameter values ​​corresponding to the strongest resonance peak recorded in step S204, respectively, to achieve self-injection locking. At this time, the system enters a stable working state, and the photodetector outputs a low phase noise frequency signal.

[0062] Long-term stable maintenance: The system continuously monitors the light intensity of the first photodetector 41 and the second photodetector 42. If a continuous, monotonically decreasing light intensity is detected within a short period (e.g., the decrease exceeds a set threshold), a fine-tuning procedure is executed, slightly adjusting the laser current along the previously locked direction to find a new maximum light intensity. If an unpredictable jump or significant drop in light intensity occurs, it is determined to be a loss of lock, and the system returns to the laser scanning and lock identification steps, performing a small-scale rescan and lock on that laser path.

[0063] This application provides a low-phase-noise high-frequency signal generation device based on a key-type optical reference source, which has the following advantages: By integrating self-injection locking technology, automated control algorithms, and the use of a dual-laser shared microcavity and photodetector, the device achieves tunable key-based operation and low phase noise frequency generation. After automatically completing initial locking, the device can maintain highly stable operation for extended periods through real-time monitoring and feedback control, without requiring complex active frequency-locking optical paths and circuits. This compact device generates continuously tunable low phase noise frequency signals and exhibits excellent common-mode noise suppression, providing an efficient and reliable solution for integrated, chip-based high-performance microwave photonic signal sources.

[0064] A second aspect of this application provides a method for generating low-phase-noise high-frequency signals based on a keyed optical reference source, applicable to the low-phase-noise high-frequency signal generation apparatus based on a keyed optical reference source described in any of the above embodiments, comprising: The first and second lasers are emitted to the first optical filter; The first laser and the second laser are combined and then input into a high-quality factor optical microcavity; the high-quality factor optical microcavity transmits the combined laser beam into a first combined laser beam and a second combined laser beam; the first combined laser beam is input into a photoelectric detection module, and the second combined laser beam is input into a second optical filter; The second combined laser beam is split into a first split laser beam and a second split laser beam, and then input into the photoelectric detection module respectively; Based on the first combined laser beam, a difference frequency signal is generated; the difference frequency signal is a low phase noise microwave or terahertz wave signal. Determine the light intensity values ​​of the first and second split laser beams; Obtain the target output frequencies of the first laser and the second laser; Based on the target output frequency, the required resonant frequencies for locking the first laser and the second laser to the high-quality factor optical microcavity, the required laser phases for the first laser and the second laser, and the required driving voltage value for the laser control module are determined. Based on the light intensity value, the required driving voltage value, and the required resonant frequency, determine the target driving voltage value; The laser control module is driven to operate at the target driving voltage value and the desired laser phase.

[0065] It is worth noting that the effects of the above method embodiments can be found in the effects of the above system embodiments, and will not be repeated here.

[0066] The above detailed embodiments further illustrate the purpose, technical solution, and beneficial effects of the embodiments of this application. The above are merely specific implementations of the embodiments of this application and are not intended to limit the protection scope of the embodiments of this application. Any modifications, equivalent substitutions, improvements, etc., made on the basis of the technical solutions of the embodiments of this application should be included within the protection scope of the embodiments of this application.

Claims

1. A low-phase-noise high-frequency signal generation device based on a key-type optical reference source, characterized in that, include: The system comprises a laser control module (1), a first optical filter (2), a high-quality factor optical microcavity (3), a photoelectric detection module (4), a second optical filter (5), and a control module (6); the control module (6) is electrically connected to the laser control module (1) and the photoelectric detection module (4). The laser control module (1) is configured as follows: The first laser and the second laser are emitted to the first optical filter (2); The first optical filter (2) is configured as follows: The first laser and the second laser are combined and input into the high-quality factor optical microcavity (3); the high-quality factor optical microcavity (3) transmits the combined laser beam into a first combined laser beam and a second combined laser beam; the first combined laser beam is input into the photoelectric detection module (4), and the second combined laser beam is input into the second optical filter (5). The second optical filter (5) is configured as follows: The second combined laser beam is split into a first split laser beam and a second split laser beam, and then input into the photoelectric detection module (4) respectively. The photoelectric detection module (4) is configured as follows: Based on the first combined laser beam, a difference frequency signal is generated; the difference frequency signal is a low phase noise microwave or terahertz wave signal. Determine the light intensity values ​​of the first and second split laser beams; The control module (6) is configured as follows: Obtain the target output frequencies of the first laser and the second laser; Based on the target output frequency, the required resonant frequency of the first laser and the second laser locked to the high-quality factor optical microcavity (3), the required laser phase of the first laser and the second laser, and the required driving voltage value of the laser control module (1) are determined. Based on the light intensity value, the required driving voltage value, and the required resonant frequency, determine the target driving voltage value; The laser control module (1) is driven to operate at the target driving voltage value and the desired laser phase.

2. The low-phase-noise high-frequency signal generation device based on a key-type optical reference source according to claim 1, characterized in that, The laser control module (1) includes: First laser control component (11) and second laser control component (12); The first laser control component (11) includes: A first distributed feedback laser (111) and a first silicon-based polarization controller (112); the first distributed feedback laser (111) is used to emit a first laser to the first silicon-based polarization controller (112); the first silicon-based polarization controller (112) is used to adjust the laser phase of the first laser and input the adjusted first laser to the first optical filter (2). The second laser control component (12) includes: A second distributed feedback laser (121) and a second silicon-based polarization controller (122); the second distributed feedback laser (121) is used to emit a second laser to the second silicon-based polarization controller (122); the second silicon-based polarization controller (122) is used to adjust the laser phase of the second laser and input the adjusted second laser to the first optical filter (2).

3. The low-phase-noise high-frequency signal generation device based on a key-type optical reference source according to claim 2, characterized in that, The control module (6) is further configured as follows: Drive the first distributed feedback laser (111) and the second distributed feedback laser (121) to operate at a first required driving voltage value, so that the laser frequencies of the first laser and the second laser are within the required resonant frequency range; The maximum light intensity values ​​of the first and second beam splitters are obtained when the laser frequencies of the first and second lasers are within the required resonant frequency range. Determine the target driving voltage value corresponding to the maximum light intensity value, and drive the first distributed feedback laser (111) and the second distributed feedback laser (121) with the target driving voltage value; and drive the first silicon-based polarization controller (112) and the second silicon-based polarization controller (122) to operate with the desired laser phase.

4. The low-phase-noise high-frequency signal generation device based on a key-type optical reference source according to claim 1, characterized in that, The photoelectric detection module (4) includes: a first photoelectric detector (41), a second photoelectric detector (42) and a third photoelectric detector (43). The first photodetector (41) is used to receive the first split laser beam input from the second optical filter (5) and determine the light intensity value of the first split laser beam to send to the control module (6). The second photodetector (42) is used to receive the second split laser beam input from the second optical filter (5) and determine the light intensity value of the second split laser beam to be sent to the control module (6). The third photodetector (43) is used to receive the first combined laser beam input from the high-quality factor optical microcavity (3) and generate a difference frequency signal based on the first combined laser beam to be sent to the control module (6).

5. The low-phase-noise high-frequency signal generation device based on a key-type optical reference source according to claim 1, characterized in that, The device further includes: Temperature control module (7), which is electrically connected to control module (6); the temperature control module (7) includes: a semiconductor cooling chip (71) and a thermistor monitoring unit (72); The semiconductor cooling chip (71) is used to regulate the operating temperature within the device; The thermistor monitoring unit (72) is used to obtain the temperature value inside the device.

6. The low-phase-noise high-frequency signal generation device based on a key-type optical reference source according to claim 5, characterized in that, The control module (6) is also configured to: Based on the target output frequency, determine the required operating temperature value of the device and the second required driving voltage value of the temperature control module (7); The temperature control module (7) is driven to operate at the second required driving voltage value, so that the temperature value inside the device is within the required operating temperature range.

7. The low-phase-noise high-frequency signal generation device based on a key-type optical reference source according to claim 6, characterized in that, The temperature control module (7) is configured as follows: Determine whether the temperature value inside the device is within the required operating temperature range; If not, the semiconductor cooling chip (71) is driven to increase power or stop operating so that the temperature value inside the device is restored to the required operating temperature range.

8. The low-phase-noise high-frequency signal generation device based on a key-type optical reference source according to claim 1, characterized in that, The control module (6) is also configured to: Determine whether the first and second lasers have drifted; If so, the steps of determining the required resonant frequency of the first laser and the second laser to be locked to the high-quality factor optical microcavity (3), the required laser phase of the first laser and the second laser, and the required driving voltage value of the laser control module (1) based on the target output frequency are repeated.

9. The low-phase-noise high-frequency signal generation device based on a key-type optical reference source according to claim 1, characterized in that, The high-quality factor optical microcavity (3) is any one of micro-ring resonator, micro-disk cavity, whispering corridor mode optical microcavity or photonic crystal microcavity.

10. A method for generating low-phase-noise high-frequency signals based on a key-type optical reference source, applied to the low-phase-noise high-frequency signal generation apparatus based on a key-type optical reference source as described in any one of claims 1 to 9, characterized in that, include: The first and second lasers are emitted to the first optical filter; The first laser and the second laser are combined and then input into a high-quality factor optical microcavity; the high-quality factor optical microcavity transmits the combined laser beam into a first combined laser beam and a second combined laser beam; the first combined laser beam is input into a photoelectric detection module, and the second combined laser beam is input into a second optical filter; The second combined laser beam is split into a first split laser beam and a second split laser beam, and then input into the photoelectric detection module respectively; Based on the first combined laser beam, a difference frequency signal is generated; the difference frequency signal is a low phase noise microwave or terahertz wave signal. Determine the light intensity values ​​of the first and second split laser beams; Obtain the target output frequencies of the first laser and the second laser; Based on the target output frequency, the required resonant frequencies for locking the first laser and the second laser to the high-quality factor optical microcavity, the required laser phases for the first laser and the second laser, and the required driving voltage value for the laser control module are determined. Based on the light intensity value, the required driving voltage value, and the required resonant frequency, determine the target driving voltage value; The laser control module is driven to operate at the target driving voltage value and the desired laser phase.

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