Driving method and circuit of acousto-optic modulator with arbitrary timing and frequency

Abstract

The application provides a driving method of an acousto-optic modulator with arbitrary time sequence and frequency, which comprises the following steps: S1, presetting frequency control parameters containing a plurality of control sections, and sequentially arranging the control sections according to the working execution process of the acousto-optic modulator; S2, acquiring a first control section in the frequency control parameters in response to a control instruction; S3, outputting a corresponding frequency according to the currently acquired control section and maintaining the corresponding time; S4, acquiring a next control section in the frequency control parameters and repeating step S3 until the last control section is executed completely. The application can realize the change of multiple light frequencies through one acousto-optic modulator, significantly reduces the complexity of a quantum precision measurement light path, and can meet the requirements for frequency time length, precision and stability in the quantum precision measurement process.

Description

Technical Field

[0001] This invention relates to the driving technology of acousto-optic modulators, and more specifically, to a driving method and circuit for an acousto-optic modulator with arbitrarily set timing and frequency. Background Technology

[0002] With the continuous advancement of cold atom technology, how to rapidly cool and trap atoms has become one of the key technical challenges in this field. In existing technologies, acousto-optic modulation is generally used to shift the frequency of laser light, combined with techniques such as magneto-optical traps to cool and trap atoms. An acousto-optic modulator (AOM) indirectly influences and manipulates the quantum state of cold atoms through processes such as laser frequency shifting. As the complexity of quantum precision measurement processes continues to increase, the number of AOMs required for a single optical path system is increasing, making the optical system more complex. Simultaneously, the required measurement accuracy also needs further improvement, thus the frequency output by the AOM driving circuit needs to be maintained for longer periods, sometimes reaching several seconds; and the frequency of the driving signal needs to achieve very high precision and stability. Therefore, the development of quantum precision measurement requires a driving method that can rapidly shift the laser frequency using a single AOM, and the timing of the frequency transformation can be arbitrarily set according to experimental requirements. However, currently, there is no AOM driving method that meets these requirements.

[0003] With the development of quantum precision measurement technology, some acousto-optic modulator driving methods have emerged. For example, Chinese patent application No. 2016111034782 discloses an acousto-optic modulator driving system with the following technical solution: it includes a signal generation circuit adapted to generate a microwave signal of a specific frequency; an adjustable attenuation circuit connected to the signal generation circuit, adapted to adjust the attenuation of the power of the microwave signal generated by the signal generation circuit to obtain a microwave signal with adjustable power within a certain range; a power amplification circuit connected to the adjustable attenuation circuit, adapted to amplify the microwave signal modulated by the adjustable attenuation circuit to obtain a microwave signal with the required power; and a radio frequency switch circuit located between the attenuation circuit and the power amplification circuit, controlling the microwave signal transmission between the adjustable attenuation circuit and the power amplification circuit through its own switching on and off. This driving scheme initially realizes the normal operation of the acousto-optic modulator. However, this driving method can generally only output at one frequency and cannot switch frequencies. This makes it impossible to use an acousto-optic modulator to generate laser frequency shifts of multiple frequencies. Ultimately, this results in an extremely complex optical system structure required for quantum precision measurement, which affects the miniaturization of quantum precision measurement systems and makes it impossible to effectively reduce costs due to system complexity.

[0004] Chinese patent application CN106200029A discloses a driving circuit and scanning method for an acousto-optic modulator. The driving circuit includes a controller, a phase-locked loop (PLL), a direct digital frequency synthesizer (DFD), a digital-to-analog converter (DAC), and a variable gain amplifier module. A variable gain amplifier module is added to the output terminals of both the DFD and DAC. This module amplifies the amplitude of the signal output from the DFD, and the amplification factor is controlled by the output of the DAC. This allows for adjustable frequency and amplitude values ​​of the output signal from the acousto-optic modulator driving circuit. The controller enables the driving circuit to flexibly and quickly switch or scan the frequency and amplitude of the output signal. The scanning method provided by this solution allows for preset or custom scanning points, thus offering more scanning options. This solution enables a driving method with adjustable output frequency. However, this approach is unsuitable for driving acousto-optic modulators in the field of quantum precision measurement due to the following significant drawbacks: First, the scanning method described in this scheme is an interval-based scanning method using points as units, with a 10ns time interval between two scanning points as an adjustment unit. However, the output power used in quantum precision measurement sometimes needs to remain stable at a certain level for more than 2 seconds before the next change, and the change pattern must be constantly adjusted according to experimental requirements, allowing for arbitrary timing settings. This scanning method lacks flexibility and is unsuitable for quantum precision measurement. Second, the control method described in this scheme heavily relies on the RAM storage size of the FPGA. The patent indicates that the maximum number of amplitude-frequency points can only reach 4096, making it impossible to achieve more diverse frequency timing designs. This, in turn, increases the manufacturing requirements of the acousto-optic modulator driver, increases cost, and complicates documentation. Third, the control method described in this scheme requires continuous frequency sampling, which introduces crosstalk signals that affect the experiment, leading to unstable final output signals and ultimately affecting the measurement accuracy of quantum precision measurements.

[0005] Therefore, the acousto-optic modulation drive used in quantum precision measurement needs a relatively simple, reliable, economical and practical driving method that can set arbitrary timing and frequency, and the driving signal is stable and interference-free. Summary of the Invention

[0006] To address the aforementioned technical problems, the primary objective of this invention is to provide a driving method for an acousto-optic modulator with arbitrarily set timing and frequency. This method enables the alteration of multiple optical frequencies using a single acousto-optic modulator, significantly reducing the complexity of the optical path in quantum precision measurement. Simultaneously, it meets the requirements for frequency duration, accuracy, and stability during quantum precision measurement.

[0007] A second objective of the present invention is to provide a driving circuit for implementing the above-described driving method for an acousto-optic modulator with arbitrarily set timing and frequency.

[0008] A third objective of the present invention is to provide a storage medium storing a computer program for executing the above-described driving method for an acousto-optic modulator with arbitrarily set timing and frequency.

[0009] To achieve the above objectives, one aspect of the present invention provides a driving method for an acousto-optic modulator with arbitrarily set timing and frequency, the method comprising the following steps:

[0010] S1: Preset frequency control parameters containing multiple control sections, and arrange each control section sequentially according to the working process of the acousto-optic modulator;

[0011] S2: In response to the control command, obtain the first control section in the frequency control parameters;

[0012] S3: Output the corresponding frequency based on the currently acquired control section and maintain it for the corresponding time;

[0013] S4: Obtain the next control section in the frequency control parameters and repeat step S3 until the last control section is executed.

[0014] Preferably, steps S2 and S3 are executed through the S / H module.

[0015] Preferably, in step S1, the control section includes output frequency, output power, output time point, and output duration.

[0016] Preferably, the timing of multiple control sections is executed sequentially according to the driving process of the acousto-optic modulator.

[0017] Another aspect of the present invention provides a driving circuit for implementing the above-described driving method for an acousto-optic modulator with arbitrarily set timing and frequency. The circuit includes a control memory and a driving execution unit. The control memory is connected to the driving execution unit via an S / H module, and the output terminal of the driving execution unit is connected to the acousto-optic modulator. Wherein:

[0018] The control memory contains preset frequency control parameters for multiple control sections. These control sections are arranged sequentially according to the working process of the acousto-optic modulator. When the control memory receives a control command, it controls the control sections through the S / H module and controls the drive execution unit to output the corresponding frequency and maintain it for the corresponding time according to the control sections, until the timing of all control sections has been completed.

[0019] Preferably, the drive execution unit includes a frequency generation module, a control memory, a direct digital frequency synthesizer, a low-pass filter, a power adjustment module, and a power amplification module, wherein the frequency generation module, the direct digital frequency synthesizer, the low-pass filter, the power adjustment module, and the power amplification module are connected in sequence; the control terminal of the control memory is connected to the host computer, and the output terminal of the control memory is connected to the direct digital frequency synthesizer through an S / H module.

[0020] Preferably, the power adjustment module and the power amplification module are connected via an RF switch module.

[0021] Preferably, the control memory includes an FPGA or a microcontroller.

[0022] In one aspect, the present invention provides a storage medium storing a computer program, which, when processed and executed, implements the driving method of an acousto-optic modulator with arbitrarily set timing and frequency as described above.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0024] The design of this invention enables the frequency of the radio frequency signal driving the acousto-optic modulator to be changed, and the timing changes of the signal frequency can be controlled without any limitations. Compared with traditional acousto-optic modulators, it achieves adjustable output signal frequency by controlling the frequency multiplication factor of the acquired signal. Multiple optical frequencies can be changed with a single acousto-optic modulator, significantly reducing the complexity of the optical path in quantum precision measurement and reducing costs. At the same time, this invention maintains the frequency through the S / H method. Compared with the existing method of scanning by frequency points, it does not need to be limited to 10ns increments. The desired frequency can be set for any duration. With the same number of sweep points, more diverse frequency settings can be made, and the frequency maintenance time can be longer to meet the requirements of longer time scale settings. Thus, the frequency maintenance time can reach more than 2s before the next frequency change, improving the test accuracy of quantum precision measurement. This invention replaces the scheme of continuous frequency sampling with a frequency maintenance scheme. The scanning frequency and scanning period of the control script can be changed according to the user's actual measurement needs. Because communication only occurs during frequency changes and there are no other signals during the maintenance phase, this method can effectively reduce the introduction of noise and improve the accuracy and stability of the output frequency. Attached Figure Description

[0025] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments of this application and their descriptions are used to explain this application and do not constitute a limitation thereof.

[0026] Figure 1 This is a flowchart illustrating the implementation of the method described in this embodiment of the invention;

[0027] Figure 2 This is a connection structure diagram of the driving circuit described in the embodiment of the present invention. Detailed Implementation

[0028] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0029] It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0030] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0031] Based on the problems in the background technology and the technical solution of the present invention, this embodiment first provides a driving method for an acousto-optic modulator that can be set with arbitrary timing and frequency, such as... Figure 1 As shown, the method includes the following steps:

[0032] S1: Preset frequency control parameters containing multiple control sections, and arrange each control section sequentially according to the working process of the acousto-optic modulator;

[0033] S2: In response to the control command, obtain the first control section in the frequency control parameters;

[0034] S3: Output the corresponding frequency based on the currently acquired control section and maintain it for the corresponding time;

[0035] S4: Obtain the next control section in the frequency control parameters and repeat step S3 until the last control section is executed.

[0036] As a preferred implementation scheme, steps S2 and S3 are executed through the S / H module. The S / H module is a frequency sampling and maintenance mechanism. Specifically, it controls the FPGA to acquire a frequency code control section (containing output frequency, output power, output status, and maintenance length of the section), and maintains the frequency based on the maintenance length of the section. After the frequency maintenance time set in the code file ends, it controls the sampling of the next frequency code control section, thus realizing the change of frequency and the setting of arbitrary frequency timing. The frequency code control sections contained in a complete timing sequence can be provided by the host computer at once and temporarily stored in the control memory module. In this way, frequency maintenance via the S / H method, compared to existing point-frequency scanning methods, does not require limitation to 10ns increments. The desired frequency can be set for any duration, allowing for more diverse frequency settings with the same number of sweep points. This enables longer frequency maintenance times, meeting longer timescale requirements, and allowing for frequency maintenance times exceeding 2 seconds before proceeding to the next frequency conversion, thus improving the testing accuracy of quantum precision measurements. Furthermore, this invention replaces continuous frequency sampling with a frequency maintenance scheme, reducing introduced digital noise and improving the accuracy and stability of the output frequency.

[0037] It should be noted that using the frequency sustaining time method of the S / H module allows for the sequential arrangement and combination of the required frequencies. Compared with the point frequency scanning method, the frequency sustaining method has no unit time limit, enabling arbitrary duration settings for the desired frequency change. Furthermore, with the same number of sweep points, more diverse frequency settings can be performed, and the frequency sustaining time can meet the requirements of longer time scales. The frequency sustaining scheme replaces the scheme of continuous frequency sampling, reducing the introduced digital noise and improving the accuracy and stability of the output frequency. By controlling the frequency multiplication factor of the acquired signal through FPGA, the frequency of the output signal is adjustable. Multiple optical frequencies can be changed through a single acousto-optic modulator, significantly reducing the complexity of the optical path structure for quantum precision measurement and significantly reducing costs.

[0038] As a preferred implementation, in step S1, the control section includes output frequency, output power, output time point, and output duration.

[0039] As a preferred implementation, the timing of multiple control sections is executed sequentially according to the driving process of the acousto-optic modulator.

[0040] In summary, this scheme is particularly suitable for quantum precision measurement systems that require continuous scanning and frequency switching, and whose output frequency needs to be maintained on the order of seconds or higher. The AOM (Acousto-Optical Array) is driven by a sinusoidal electrical signal. The operating state of the AOM can be determined by changing the frequency and power of the input signal. Thus, the output frequency of the acousto-optic modulator is scan-varying, with adjustable sweep period and sweep range. The control script input to the control memory (such as an FPGA) maintains the desired frequency value for a certain time (this time can be arbitrarily set) using the S / H method. After the preset time, the frequency value is instantly changed and maintained for a further period. When the written code file itself determines a change in output frequency, the output frequency of the drive circuit also changes, thereby controlling the frequency generated internally by the AOM, and consequently changing parameters such as the laser frequency. The scanning frequency and scan period of the control script can be changed according to the user's actual measurement needs. Because communication only occurs during frequency changes, and there are no other signals during the hold phase, this method effectively reduces noise introduction and improves the accuracy and stability of the output frequency.

[0041] The technical features of this invention employ a driving method that uses a control code file and an S / H method to control frequency changes and maintain them for a preset time; the driving circuit controls the frequency holding time through the S / H method; by executing the frequency and holding time preset by the code file stored in the control memory, the output frequency value and its holding time are changed; thereby realizing that the output frequency of the AOM driving circuit is adjustable and the timing can be arbitrarily set.

[0042] This embodiment also provides a driving circuit for implementing the above-described driving method for an acousto-optic modulator with arbitrarily set timing and frequency. The circuit includes a control memory and a driving execution unit. The control memory is connected to the driving execution unit via an S / H module, and the output of the driving execution unit is connected to the acousto-optic modulator. Wherein:

[0043] The control memory contains preset frequency control parameters for multiple control sections. When the control memory receives a control command, it controls the control section through the S / H module and controls the drive execution unit to output the corresponding frequency and maintain it for the corresponding time according to the control section, until the timing of all control sections is completed.

[0044] As a preferred implementation scheme, such as Figure 2 As shown, the drive execution unit includes a frequency generation module, a control memory, a direct digital frequency synthesizer, a low-pass filter, a power adjustment module, and a power amplification module, wherein the frequency generation module, the direct digital frequency synthesizer, the low-pass filter, the power adjustment module, and the power amplification module are connected in sequence; the control terminal of the control memory is connected to the host computer, and the output terminal of the control memory is connected to the direct digital frequency synthesizer through an S / H module.

[0045] In a preferred embodiment, the power adjustment module and the power amplification module are connected via an RF switch module. Specifically, the frequency generation module output reference is connected to the input of the direct digital frequency synthesizer (DDS). After the DDS outputs a differential signal, its output is connected to the input of a low-pass filter. The low-pass filter filters the signal, outputting a lower-noise signal, which is then connected to the power adjustable module. After adjusting the desired frequency power to a preset value, the module is connected to the RF switch module. A multi-stage switch is used to improve the isolation of the switches. The RF switch module, controlled by a control signal, enables rapid switching between on and off of the RF signal. Finally, the output of the RF switch module is connected to the input of the power amplification module to amplify the set frequency. The output of the power amplification module then outputs the RF signal. Simultaneously, a control memory is connected to the control terminal of the DDS. The control memory stabilizes the output frequency of the DDS using the S / H method and can control the DDS to change its output power.

[0046] More specifically, the input of the direct digital frequency synthesizer is connected to the frequency generation module to receive the reference frequency. Its control terminal is connected to the FPGA, which controls the process of multiplying the reference frequency by n and maintaining the frequency. Then, the output terminal outputs a differential signal.

[0047] More specifically, the input of the low-pass filter is connected to the output of the direct digital frequency synthesizer to filter out clutter signals outside a specific frequency before outputting them. This can improve the stability of the output signal, reduce the impact of clutter signals on the final acousto-optic modulator, and improve the accuracy and stability of quantum precision measurement experiments.

[0048] More specifically, the input of the power adjustment module is connected to the output of the low-pass filter. After the signal enters the module, it undergoes the first stage of amplification according to the settings written into the FPGA code file according to user requirements.

[0049] More specifically, the input terminal of the RF switch module is connected to the output terminal of the power adjustment module. This module receives a TTL control signal through its control terminal to achieve rapid switching between the on and off of the RF signal.

[0050] More specifically, the input terminal of the power amplifier module is connected to the output terminal of the radio frequency switch module. This module is an amplifier with a fixed amplification ratio. Through this module, the output signal of the acousto-optic modulator drive circuit is amplified, and finally a sinusoidal electrical signal is output to drive the acousto-optic modulator to realize laser frequency shifting.

[0051] As a preferred implementation, the control memory is used to store the code file sent by the PC, and to control the frequency and duration of the output of the drive circuit by executing this code. The control memory can be an FPGA, an ARM, or even a microcontroller. In this invention, an FPGA is used as the control memory.

[0052] Combination Figure 1 When executing the above driving method, a code file containing the required output frequency, amplitude, and corresponding duration of the driving circuit is first preset and stored in the storage controller (FPGA). When the host computer issues a command, the storage controller receives the command and reads the scan file in the code file. According to the settings in the code, it controls the FPGA to acquire a frequency code control section and times the duration of the section to maintain the frequency (S / H module). After the duration of the frequency set in the code file ends, the controller controls the sampling of the next frequency code control section, changes the output frequency and amplitude, and maintains it for the required time. The above operation is repeated until all the preset timing sequences in the code file have ended and a termination command is issued, at which point the acousto-optic modulator driver stops working. This process completes the adjustable frequency, power, and timing combination of the acousto-optic modulator driver output.

[0053] This embodiment also provides a storage medium storing a computer program, which, when processed and executed, implements the driving method of the acousto-optic modulator with arbitrarily set timing and frequency as described above.

[0054] This invention discloses a driving method for an acousto-optic modulator (AOM) with configurable timing and frequency, particularly suitable for quantum precision measurement systems requiring continuous scanning and frequency switching, and maintaining the output frequency on the order of seconds or higher. The AOM is driven by a sinusoidal electrical signal, whose operating state can be determined by changing the frequency and power of the input AOM. The control script input to the FPGA maintains the desired frequency value for a certain time (arbitrarily settable) using the S / H method. After the preset time, the frequency value is instantly changed and maintained for a further period. When the written code file itself determines a change in output frequency, the output frequency of the driving circuit also changes, thereby controlling the frequency generated internally by the AOM and consequently altering parameters such as the laser frequency. The scanning frequency and scanning period of the control script can be varied according to the user's actual measurement needs. Because communication only occurs during frequency changes, and no other signals are present during the holding phase, this method effectively reduces noise introduction and improves the accuracy and stability of the output frequency.

[0055] The technical features of this invention employ a driving method that uses a control code file and an S / H method to control frequency changes and maintain them for a preset time. The driving circuit controls the frequency holding time using the S / H method. By executing the frequency and holding time preset in the code file stored in the FPGA, the output frequency value and its holding time are changed. This enables the AOM driving circuit to have an adjustable output frequency and arbitrarily set timing.

[0056] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention without departing from the principles and spirit of the present invention. Any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A driving method of an arbitrary timing and frequency settable acoustooptic modulator, characterized by, The driving circuit comprises a control memory and a driving execution unit, the control memory is connected with the driving execution unit through an S / H module, and an output end of the driving execution unit is connected with an acousto-optic modulator; The driving method comprises the following steps: S1: presetting frequency control parameters containing a plurality of control sections in the control memory, and sequentially arranging the control sections according to the working execution process of the acousto-optic modulator; S2: acquiring a first control section in the frequency control parameters in response to a control instruction; S3: outputting a corresponding frequency according to the currently acquired control section and maintaining the corresponding time; S4: acquiring a next control section in the frequency control parameters and repeating step S3 until the last control section is executed completely; The control section comprises an output frequency, an output power, an output time point and a maintenance length of the control section; Steps S2 and S3 are executed through the S / H module; the S / H module is a frequency sampling and maintaining mechanism, which controls the collection of a frequency code control section in the control memory, and realizes the maintenance of the frequency according to the maintenance time length of the control section; after the frequency maintenance time set in the frequency code control section is over, the next frequency code control section is sampled, so that the change of the frequency and the arbitrary timing setting of the frequency are realized; a complete timing contains frequency code control sections which can be provided by an upper computer and temporarily stored in the control memory at one time.

2. The method of claim 1, wherein the method is characterized by: The timing expressed by a plurality of control sections is sequentially executed according to the driving process of the acousto-optic modulator.

3. A driving circuit for implementing the driving method of the arbitrary timing and frequency settable acousto-optic modulator according to claim 1 or 2, characterized by, The driving circuit comprises a control memory and a driving execution unit, the control memory is connected with the driving execution unit through an S / H module, and an output end of the driving execution unit is connected with an acousto-optic modulator; wherein: The control memory is preset with frequency control parameters containing a plurality of control sections, when the control memory receives a control instruction, the control section is acquired through the S / H module, and the driving execution unit is controlled to output a corresponding frequency and maintain the corresponding time according to the control section, until the timing of all control sections is executed completely.

4. The drive circuit according to claim 3, characterized in that, The driving execution unit comprises a frequency generation module, a direct digital frequency synthesizer, a low-pass filter, a power adjustment module and a power amplifier module, wherein the frequency generation module, the direct digital frequency synthesizer, the low-pass filter, the power adjustment module and the power amplifier module are sequentially connected; a control end of the control memory is connected with an upper computer, and an output end of the control memory is connected with the direct digital frequency synthesizer through the S / H module.

5. The drive circuit according to claim 4, characterized in that, The power adjustment module and the power amplifier module are connected through a radio frequency switch module.

6. The drive circuit according to claim 3, characterized by The control memory comprises an FPGA or a single-chip microcomputer.

7. A storage medium storing a computer program, characterized by The computer program is processed and executed, and the driving method of the acousto-optic modulator with arbitrary timing and frequency can be set as claimed in claim 1 or 2.

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