Dual optical frequency comb ranging system, method, control device and storage medium

Abstract

The application belongs to the technical field of double optical frequency comb ranging, and provides a double optical frequency comb ranging system, method, control device and storage medium, the system comprising a first optical frequency comb, a second optical frequency comb, a circulator, a first coupler and a second coupler; the ranging light signal generated by the first optical frequency comb at a first repetition frequency is transmitted to the first coupler through the circulator, and then transmitted to a mirror and an object to be measured through the first coupler; the reference light signal generated by the second optical frequency comb at a second repetition frequency is transmitted to the second coupler; the first reflected light signal reflected by the mirror and the second reflected light signal reflected by the object to be measured are transmitted to the second coupler through the first coupler and the circulator; the reference light signal and the two reflected light signals interfere to generate an interference light signal in the second coupler; the second repetition frequency is k times of the first repetition frequency, k is a decimal greater than 1, and at least one repetition frequency is adjustable. The ranging rate of the double optical frequency comb ranging system provided by the application can be flexibly adjusted in a wide range.

Description

Technical Field

[0001] This application belongs to the field of optical frequency comb (OFC) ranging technology, and particularly relates to a optical frequency comb ranging system, method, control device and storage medium. Background Technology

[0002] Currently, optical frequency combs are widely used in optical atomic clocks, distance measurement, spectral ranging, coherent optical communication, radio frequency signal generation, and bioimaging. Distance measurement systems based on dual optical frequency combs can achieve ranging accuracy on the order of nanometers, ranging speed on the order of MHz, and ranging distance on the order of km by utilizing the "vernier effect" between two optical frequency combs with slightly different repetition frequencies. However, the ranging speed of existing dual optical frequency comb ranging systems cannot be flexibly adjusted over a wide range. Summary of the Invention

[0003] This application provides a dual-frequency comb ranging system, method, control device, and storage medium to solve the problem that the ranging rate of existing dual-frequency comb ranging systems cannot be flexibly adjusted over a wide range.

[0004] The first aspect of this application provides a dual-optical-frequency-comb ranging system, including a first optical-frequency comb, a second optical-frequency comb, a circulator, a first coupler, and a second coupler;

[0005] The first optical frequency comb is used to generate a ranging optical signal at a first repetition frequency. The ranging optical signal is transmitted to the first coupler via the circulator, and then split by the first coupler and transmitted to the reflector and the object to be measured respectively.

[0006] The second optical frequency comb is used to generate a reference optical signal at a second repetition frequency, and the reference optical signal is transmitted to the second coupler;

[0007] The first reflected light signal reflected by the mirror and the second reflected light signal reflected by the object under test are combined by the first coupler and then transmitted to the second coupler via the circulator.

[0008] The reference optical signal, the first reflected optical signal, and the second reflected optical signal interfere in the second coupler to generate an interference optical signal that is transmitted to the ranging device.

[0009] The ranging device is used to perform photoelectric conversion and low-pass filtering on the interference light signal to obtain the modulation envelope and acquire the time domain information of the modulation envelope, thereby obtaining the distance information of the object to be measured.

[0010] Wherein, the second repetition frequency is the first repetition frequency. The second repetition frequency is times that of The difference between the first repetition frequency and the second repetition frequency is equal to the ranging rate of the dual-frequency comb ranging system, and at least one of the first repetition frequency and the second repetition frequency is adjustable. For decimals greater than 1, for The value after rounding down to the nearest integer.

[0011] In one embodiment, the wavelengths of the ranging optical signal and the reference optical signal include at least one of the ultraviolet band, visible light band, near-infrared band, and mid-infrared band.

[0012] In one embodiment, the first optical frequency comb and the second optical frequency comb are respectively one of a mode-locked laser optical frequency comb, an electro-optic modulation optical frequency comb, and a microcavity optical frequency comb.

[0013] In one embodiment, the mode-locked laser optical frequency comb is an erbium-doped fiber mode-locked laser optical frequency comb, a ytterbium-doped fiber mode-locked laser optical frequency comb, or a Ti:sapphire mode-locked laser optical frequency comb.

[0014] The electro-optic modulated optical frequency comb is generated by phase modulation of a continuous optical signal using an external radio frequency signal.

[0015] The microcavity optical frequency comb is a microring optical frequency comb, microsphere optical frequency comb, or microdisk optical frequency comb based on at least one of silicon, silicon dioxide, silicon nitride, lithium niobate, calcium fluoride, and magnesium fluoride.

[0016] A second aspect of this application provides a dual-frequency comb ranging method, implemented based on the dual-frequency comb ranging system provided in the first aspect of this application. The method includes:

[0017] Obtain the user's input command for adjusting the repetition frequency;

[0018] According to the repetition frequency adjustment command, at least one of the first repetition frequency and the second repetition frequency is adjusted to adjust the ranging rate.

[0019] In one embodiment, the method further includes:

[0020] Based on the time-domain information, the modulation envelope delay is obtained;

[0021] Based on the second repetition frequency and the ranging rate, the equivalent amplification factor of the first optical frequency comb and the second optical frequency comb is obtained;

[0022] The distance to the object under test is obtained based on the modulation envelope delay and the equivalent amplification factor.

[0023] In one embodiment, the formula for calculating the ranging rate is:

[0024]

[0025] The formula for calculating the equivalent magnification is:

[0026]

[0027] The formula for calculating the distance is:

[0028]

[0029] in, This represents the first repetition frequency. This indicates the second repetition frequency. This indicates the ranging rate. This indicates the equivalent magnification factor. Indicates the distance, This represents the speed of light in a vacuum. This indicates the time delay between the first reflected light signal and the second reflected light signal. This indicates the modulation envelope delay.

[0030] A third aspect of this application provides a control device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the steps of the dual-frequency comb ranging method provided in the second aspect of this application.

[0031] A fourth aspect of this application provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps of the dual-frequency comb ranging method provided in the second aspect of this application.

[0032] The fifth aspect of this application provides a dual optical frequency comb ranging system, which, based on the dual optical frequency comb ranging system provided in the first aspect of this application, also includes the control device provided in the third aspect of this application.

[0033] The control device is electrically connected to the first optical frequency comb, the second optical frequency comb, and the ranging device, respectively, and the control device is used for:

[0034] Control the first optical frequency comb to generate a ranging optical signal at a first repetition frequency;

[0035] Control the second optical frequency comb to generate a reference optical signal at a second repetition frequency;

[0036] Based on the time-domain information, the distance information of the object to be measured is obtained.

[0037] The first aspect of this application provides a dual-frequency comb ranging system, including a first frequency comb, a second frequency comb, a circulator, a first coupler, and a second coupler. The first frequency comb generates a ranging optical signal at a first repetition frequency. The ranging optical signal is transmitted to the first coupler via the circulator, and then split by the first coupler and transmitted to a reflector and a target object, respectively. The second frequency comb generates a reference optical signal at a second repetition frequency, which is transmitted to the second coupler. The first reflected optical signal reflected by the reflector and the second reflected optical signal reflected by the target object are combined via the first coupler and transmitted to the second coupler via the circulator. The reference optical signal, the first reflected optical signal, and the second reflected optical signal interfere in the second coupler to generate an interference optical signal, which is transmitted to the ranging device. The ranging device performs photoelectric conversion and low-pass filtering on the interference optical signal to obtain a modulation envelope and acquire the time-domain information of the modulation envelope, thereby obtaining the distance information of the target object. The system achieves this by making the second repetition frequency equal to the first repetition frequency. The second repetition frequency is times that of The difference between the first and second repetition frequencies is equal to the ranging rate of the dual-frequency comb ranging system. At least one of the first and second repetition frequencies is adjustable. For decimals greater than 1, for The rounded-down value can be used to flexibly adjust the ranging rate of the dual-optical-frequency comb ranging system by adjusting the repetition frequency of the dual-optical-frequency comb, according to actual needs.

[0038] It is understood that the beneficial effects of the second to fifth aspects mentioned above can be found in the relevant descriptions in the first aspect mentioned above, and will not be repeated here. Attached Figure Description

[0039] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0040] Figure 1 This is a schematic diagram of the first structure of the dual optical frequency comb ranging system provided in the embodiments of this application;

[0041] Figure 2 This is a schematic diagram of the second structure of the dual optical frequency comb ranging system provided in the embodiments of this application;

[0042] Figure 3 This is a schematic diagram of the third structure of the dual optical frequency comb ranging system provided in the embodiments of this application;

[0043] Figure 4This is a schematic diagram of the first step of the dual-frequency comb ranging method provided in the embodiments of this application;

[0044] Figure 5 This is a schematic diagram of the second process of the dual-frequency comb ranging method provided in the embodiments of this application;

[0045] Figure 6 This is a schematic diagram of the third process of the dual-frequency comb ranging method provided in the embodiments of this application;

[0046] Figure 7 This is a time-intensity simulation diagram of the ranging optical signal, the reference optical signal, and the interference result between them provided in the embodiments of this application;

[0047] Figure 8 This is a time-intensity simulation diagram of the time-domain information provided in the embodiments of this application;

[0048] Figure 9 This is a time-intensity simulation diagram of the low-pass filtered interference signal provided in an embodiment of this application;

[0049] Figure 10 This is a schematic diagram of the structure of the control device provided in the embodiments of this application. Detailed Implementation

[0050] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present application.

[0051] The term "comprising," and any variations thereof, in the specification, claims, and accompanying drawings of this application are intended to cover a non-exclusive inclusion. For example, a process, method, system, product, or apparatus that comprises a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such processes, methods, products, or apparatus. Furthermore, the terms "first," "second," and "third," etc., are used to distinguish different objects, not to describe a specific order.

[0052] like Figure 1 As shown, this application provides a dual optical frequency comb ranging system, including a first optical frequency comb 11, a second optical frequency comb 12, a circulator 2, a first coupler 31, and a second coupler 32;

[0053] The first optical frequency comb 11 is used to operate at a first repetition frequency. A ranging optical signal is generated. The ranging optical signal is transmitted to the first coupler 31 via the circulator 2. After being split by the first coupler 31, it is transmitted to the reflector 411 of the first ranging arm 41 and the object 421 of the second ranging arm 42 respectively.

[0054] The second optical frequency comb 12 is used to operate at a second repetition frequency. A reference optical signal is generated and transmitted to the second coupler 32.

[0055] The first reflected light signal reflected by the reflector 411 and the second reflected light signal reflected by the object under test 421 are combined by the first coupler 31 and then transmitted to the second coupler 32 via the circulator 2.

[0056] The reference optical signal, the first reflected optical signal, and the second reflected optical signal interfere in the second coupler 32 to generate an interference optical signal that is transmitted to the ranging device 5.

[0057] The ranging device 5 is used to perform photoelectric conversion and low-pass filtering on the interference light signal to obtain the modulation envelope and acquire the time domain information of the modulation envelope, thereby obtaining the distance information of the object to be measured.

[0058] In applications, the components of a dual-frequency comb ranging system can be connected by optical fibers to form a fully fiber-optic ranging system, making the entire system easy to move and preventing interruption of the transmission optical path due to minor changes in the position of the components.

[0059] like Figure 1 As shown, an exemplary connection structure is illustrated when the components of a dual-frequency comb ranging system are connected via optical fiber, as detailed below:

[0060] The output end of the first optical frequency comb 11 is connected to the input end of the circulator 2 via an optical fiber;

[0061] The output end of the second optical frequency comb 12 is connected to the first input end of the second coupler 32 via an optical fiber;

[0062] The input and output terminals of circulator 2 are connected to the first input and output terminals of the first coupler 31 via optical fibers, and the output terminal of circulator 2 is connected to the second input terminal of the second coupler 32 via optical fibers.

[0063] The second input / output terminal of the first coupler 31 is connected to the first ranging arm 41 via an optical fiber, and the third input / output terminal of the first coupler 31 is connected to the second ranging arm 42 via an optical fiber.

[0064] The output of the second coupler 32 is connected to the input of the ranging device 5 via an optical fiber.

[0065] In the application, the first optical pulse generated by the first optical frequency comb at the first repetition frequency is used as the ranging optical signal. The ranging optical signal is first transmitted to the first coupler via the circulator, and then split into two ranging optical signals by the first coupler and transmitted to the first ranging arm and the second ranging arm respectively. The first ranging arm is equipped with a reflector for calibrating the reference position, and the second ranging arm is equipped with the object to be measured. The two ranging optical signals are reflected by the reflector of the first ranging arm and the object to be measured of the second ranging arm respectively to obtain two reflected optical signals. The two reflected optical signals are combined into one reflected optical signal by the first coupler and then transmitted to the second coupler via the circulator.

[0066] The second optical frequency comb generates a second optical pulse at a second repetition frequency, which is used as a reference optical signal. The reference optical signal is transmitted to the second coupler via a circulator.

[0067] The reference light signal and the reflected light signal interfere in the second coupler to generate an interference light signal that is transmitted to the ranging device.

[0068] In application, the second repetition frequency First repetition frequency of times, second repetition frequency and The first repetition frequency is times The difference is equal to the ranging rate of the dual-frequency comb ranging system. , For decimals greater than 1, for The value after rounding down to the nearest integer, that is , In an ideal state, It can be set to any decimal greater than 1 according to actual needs, for example, any decimal in (1, 10000], including but not limited to decimals approaching 2, 5, 10, 500, 800, 1000, 2000, 5000, 10000, etc. When it approaches 500, if the first repetition frequency If it is 100MHz, then the second repetition frequency is... Approaching 50GHz, if the second repetition frequency If it is 50GHz, then the first repetition frequency is... Approaching 100MHz.

[0069] In application, the first repetition frequency Second repetition frequency At least one of them is adjustable. Assume the first repetition frequency... The adjustment amount is Second repetition frequency The adjustment amount is The adjusted first repetition frequency for The adjusted second repetition frequency for Adjusted ranging rate , for Rounding down to the nearest integer, ranging rate adjustment amount Due to the first repetition frequency Second repetition frequency The adjustment amount is much smaller than its own, therefore, , , Among them, when only the first repetition frequency is adjusted hour When only the second repetition frequency is adjusted hour It can be seen that by making the repetition frequency of the second optical frequency comb the same as the repetition frequency of the first optical frequency comb... The first repetition frequency is adjusted by times. At that time, the corresponding adjustment amount of the ranging rate is , The magnitude of this is positively correlated with the adjustment amount of the ranging rate. The larger the value, the greater the adjustment amount of the ranging rate, the easier the adjustment, and the faster the adjustment rate.

[0070] In applications, the first and second optical frequency combs can be one of the following: mode-locked laser optical frequency comb, electro-optic modulation optical frequency comb, and microcavity optical frequency comb, respectively. The mode-locked laser optical frequency comb can be an erbium-doped fiber mode-locked laser optical frequency comb, a ytterbium-doped fiber mode-locked laser optical frequency comb, or a Ti:sapphire mode-locked laser optical frequency comb; the electro-optic modulation optical frequency comb is used to generate an optical frequency comb signal by phase modulation of a continuous optical signal through an external radio frequency signal; the microcavity optical frequency comb can be a microring optical frequency comb, a microsphere optical frequency comb, or a microdisk optical frequency comb based on at least one of silicon (Si), silicon dioxide (SiO2), silicon nitride (Si3N3), lithium niobate (LiNbO3), calcium fluoride (CaF2), and magnesium fluoride (MgF2), which can be selected according to actual needs.

[0071] In applications, the wavelengths of the ranging optical signal and the reference optical signal include at least one of the ultraviolet band, visible light band, near-infrared band, and mid-infrared band. That is, the operating wavelengths of the first optical frequency comb and the second optical frequency comb cover the ultraviolet band, visible light band, near-infrared band, and mid-infrared band.

[0072] In applications, the first and second couplers can be implemented using a power beam splitter (BS) to split and combine the incident light signal.

[0073] In applications, a reflector can be implemented using a plane reflector or a retroreflector. A reflector can also be equivalently replaced by any reflective component capable of generating a first reflected light signal by reflection.

[0074] In applications, ranging devices can be implemented using any device capable of photoelectric conversion and low-pass filtering of optical signals to obtain the modulation envelope, and then quantizing the modulation envelope to measure the distance and obtain the temporal information of the modulation envelope. Examples include photodetectors, low-pass filters, and oscilloscopes.

[0075] like Figure 2 As shown, in one embodiment, the dual optical frequency comb ranging system provided in this application further includes a first collimator 61 and a second collimator 62;

[0076] The first collimator 61 is connected to the second input / output terminal of the first coupler 31 via an optical fiber;

[0077] The second collimator 62 is connected to the third input / output terminal of the first coupler 31 via an optical fiber;

[0078] The ranging optical signal is split into two ranging optical signals by the first coupler 31. The two ranging optical signals are collimated by the first collimator 61 and the second collimator 62, and then transmitted to the first ranging arm 41 and the second ranging arm 42 respectively.

[0079] Two ranging optical signals are reflected by a reflector 411 to obtain a first reflected optical signal and by the object under test 421 to obtain a second reflected optical signal. The first and second reflected optical signals are transmitted to the first coupler 31 via the first collimator 61 and the second collimator 62 respectively, and then combined into a single reflected optical signal, which is then transmitted to the second coupler 32 via the circulator 2.

[0080] In application, the first collimator and the second collimator can be implemented by collimating lenses, which are used to collimate the two ranging optical signals so that the two ranging optical signals can be accurately incident on the two ranging arms.

[0081] like Figure 3 As shown, in one embodiment, the dual-frequency comb ranging system provided in this application further includes a first polarization controller 71 and a second polarization controller 72;

[0082] The first polarization controller 71 is connected via an optical fiber between the output end of the circulator 2 and the second input end of the second coupler 32, and is used to control the polarization state of the first reflected light signal and the second reflected light signal.

[0083] The second polarization controller 72 is connected via an optical fiber between the output end of the second optical frequency comb 12 and the first input end of the second coupler 32, and is used to control the polarization state of the reference optical signal.

[0084] In applications, a dual-frequency comb ranging system may include only one of the first polarization controller and the second polarization controller.

[0085] In one embodiment, the second rangefinder arm includes a scanning galvanometer;

[0086] When the dual-frequency comb ranging system does not include the second collimator, the scanning galvanometer is positioned between the third input / output terminal of the first coupler and the object to be measured.

[0087] When the dual-frequency comb ranging system includes a second collimator, the scanning galvanometer is positioned between the second collimator and the object to be measured.

[0088] A scanning galvanometer is used to adjust the incident position of the ranging light signal transmitted to the object under test in order to achieve two-dimensional or three-dimensional scanning of the object under test.

[0089] In applications, a scanning galvanometer can consist of a motor and a reflector that move in two-dimensional space to achieve two-dimensional scanning of the surface contour of the object under test; alternatively, it can consist of a motor and a reflector that move in three-dimensional space to achieve three-dimensional scanning of the surface contour of the object under test. By setting up a scanning galvanometer, the dual-frequency comb ranging system can not only be used to measure the absolute distance to the object under test, but also to measure the distance to the surface contour of the object under test, thus enabling two-dimensional or three-dimensional imaging of the surface contour of the object under test.

[0090] like Figure 4 As shown in the embodiment of this application, a dual-optical-frequency comb ranging method based on a dual-optical-frequency comb ranging system is also provided. Specifically, it can be executed by the processor of the control device when running the corresponding computer program. The method includes the following steps S11 to S13:

[0091] S11. Control the first optical frequency comb to generate a ranging optical signal at a first repetition frequency;

[0092] S12. Control the second optical frequency comb to generate a reference optical signal at the second repetition frequency;

[0093] S13. Obtain the distance information of the object to be measured based on the time domain information.

[0094] In applications, the control device can be electrically connected to at least one of the first optical frequency comb, the second optical frequency comb, the ranging device, and the scanning galvanometer to control the operating status of these components and achieve distance measurement of the object to be measured. The first optical frequency comb, the second optical frequency comb, the ranging device, or the scanning galvanometer can also operate automatically and independently without the control device, or the operating status of these components can be manually controlled by the user.

[0095] In applications, the control device can be a computing device capable of data processing, such as a personal computer, industrial computer, tablet computer, laptop computer, netbook, or personal digital assistant (PDA).

[0096] like Figure 5 As shown, in one embodiment, the dual-frequency comb ranging method provided in this application further includes the following steps S21 and S22 executed by the processor of the control device when running the corresponding computer program:

[0097] S21. Obtain the user-input repetition frequency adjustment command;

[0098] S21. According to the repetition frequency adjustment command, adjust at least one of the first repetition frequency and the second repetition frequency to adjust the ranging rate.

[0099] In applications, users can adjust the repetition frequency of at least one of the two optical frequency combs by inputting repetition frequency adjustment commands through any human-machine interaction method supported by the control device, according to their actual needs for the ranging rate, so as to achieve the adjustment of the ranging rate.

[0100] In applications, the control device may include or be connected to input / output devices such as display devices, keyboards, audio acquisition devices, and audio playback devices to enable human-computer interaction with the user during its operation. For example, it may display or broadcast the working status and working data of the control device and other components electrically connected to the control device, input the user's touch commands or collect the user's voice commands. The working status may include, but is not limited to, on, off, and standby. The working data may include, but is not limited to, the first repetition frequency, the second repetition frequency, time domain information, and distance information. The commands may include, but are not limited to, the repetition frequency adjustment command.

[0101] like Figure 6 As shown, in one embodiment, the dual-frequency comb ranging method provided in this application further includes the following steps S31 to S32 executed by the processor of the control device when running the corresponding computer program:

[0102] Step S31: Obtain the modulation envelope delay based on the time domain information;

[0103] Step S32: Obtain the equivalent amplification factor of the first optical frequency comb and the second optical frequency comb based on the second repetition frequency and the ranging rate;

[0104] Step S33: Obtain the distance to the object under test based on the modulation envelope delay and the equivalent amplification factor.

[0105] In applications, after low-pass filtering the interference light signal, the timing and position of the modulation envelopes corresponding to the two reflected light signals change synchronously. Therefore, the distance to the object under test can be obtained by acquiring the modulation envelope delay of the two reflected light signals.

[0106] In one embodiment, the calculation formulas for each parameter in steps S31 to S33 are as follows:

[0107] The formula for calculating the ranging rate is:

[0108]

[0109] The formula for calculating the equivalent magnification is:

[0110]

[0111] The formula for calculating distance is:

[0112]

[0113] in, Indicates the first repetition frequency. Indicates the second repetition frequency. Indicates the ranging rate, Indicates the equivalent magnification factor. Indicates distance, This represents the speed of light in a vacuum. This indicates the time delay between the first and second reflected light signals. This indicates the modulation envelope delay.

[0114] Figure 7 An exemplary time-intensity simulation diagram of the ranging optical signal, the reference optical signal, and their interference result is shown; where the horizontal axis represents time. The vertical axis represents strength. This indicates the time delay between the first and second reflected light signals. This indicates the period of the ranging optical signal. Indicates the period of the reference optical signal. Indicates a time window. Indicates the ranging rate, This represents the modulation envelope delay. Due to the detuning of the repetition frequencies of the two optical frequency combs, the ranging optical signal and the reference optical signal will align with each other at a certain moment, and will gradually drift apart until the next alignment at other moments. The interval between two alignments is called the time window. That is, the reciprocal of the measurement rate.

[0115] Figure 8 An exemplary time-intensity simulation diagram of time-domain information is shown; where the horizontal axis represents time t and the vertical axis represents intensity. Figures (a), (b), (c), and (d) respectively represent time-intensity diagrams of time-domain information when the adjustment amount of the repetition frequency of the first optical frequency comb is 300 Hz, 500 Hz, 1000 Hz, and 2000 Hz. The theoretical design value of the initial repetition frequency of the first optical frequency comb is 100 MHz, the theoretical design value of the initial repetition frequency of the second optical frequency comb is 50 GHz, the theoretical design value of the initial repetition frequency of the second optical frequency comb is 500 times the theoretical design value of the initial repetition frequency of the first optical frequency comb, the theoretical design value of the carrier frequency difference between the two optical frequency combs is 40 MHz, and the theoretical design value of the adjustment amount of the repetition frequency of the first optical frequency comb is 1 Hz. Therefore, the theoretical design value of the adjustment amount of the ranging rate of the dual optical frequency comb ranging system is 500 × 1 Hz = 500 Hz.

[0116] Depend on Figure 8 It can be seen that the intervals between adjacent envelopes in the time domain information are 6.7 μs, 4 μs, 2 μs, and 1 μs, respectively, and the corresponding ranging rates are approximately 150 kHz, 250 kHz, 500 kHz, and 1 MHz, which are consistent with the theoretical design values. Furthermore, due to the 40 MHz carrier frequency difference between the two optical frequency combs, the frequency of the modulated signal within the modulation envelope obtained after low-pass filtering is 40 MHz. As shown in the simulation diagram above, by constructing a dual-optical frequency comb ranging system using an optical frequency comb with a low repetition frequency and one with a high repetition frequency, and leveraging the flexible adjustability of the repetition frequency and the ability to achieve rapid ranging, the ranging rate of the dual-optical frequency comb ranging system can be flexibly adjusted within the range of 0 MHz to 1 MHz. Moreover, because the repetition frequencies of the two optical frequency combs differ by a large factor, only a small adjustment of the repetition frequency of the optical frequency comb with the low repetition frequency is needed to achieve a large adjustment of the ranging rate.

[0117] Figure 9 An exemplary time-intensity simulation diagram of the low-pass filtered interference signal is shown; where the horizontal axis represents time. The vertical axis represents intensity. Figures (a), (b), (c), (d), and (e) show the time-intensity simulation diagrams of the interference signals after low-pass filtering when the carrier frequency differences between the two optical frequency combs are 10 MHz, 40 MHz, 90 MHz, 5.01 GHz, and 20.04 GHz, respectively. The frequencies of the interference signals are 10 MHz, 40 MHz, 10 MHz, 10 MHz, and 40 MHz, respectively.

[0118] Depend on Figure 9 It is known that, in addition to enabling fast and wide-range ranging rate adjustment, the dual-frequency comb ranging system can also reduce the detection bandwidth requirements during high-speed ranging, thereby reducing measurement costs. The bandwidth required is only half the repetition frequency of the first frequency comb.

[0119] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0120] like Figure 10 As shown, this application embodiment also provides a control device 8, including: at least one processor 81 ( Figure 10 The diagram shows only one processor, memory 82, and computer program 83 stored in memory 82 and executable on at least one processor 81. When processor 81 executes computer program 83, it implements the steps in the various dual-frequency comb ranging method embodiments described above.

[0121] In applications, control devices may include, but are not limited to, memory and processors. Those skilled in the art will understand that... Figure 10 This is merely an example of a control device and does not constitute a limitation on the control device. It may include more or fewer devices than illustrated, or combinations of certain devices, or different devices. For example, it may also include or be connected to input / output devices, network access devices, etc. Input / output devices may include cameras, audio acquisition / playback devices, display devices, keyboards, buttons, etc. Network access devices may include communication modules for communicating with other devices, allowing users to send control commands to the control device through other devices to control the operating status of the control device (e.g., remote control), thereby enabling the control device to selectively execute the steps in various dual-optical-comb ranging method embodiments according to the user's control commands.

[0122] In applications, the processor can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. General-purpose processors can be microprocessors or any conventional processor.

[0123] In applications, the memory may be an internal storage unit of the control device in some embodiments, such as the hard drive or RAM of the control device. In other embodiments, the memory may be an external storage device of the control device, such as a plug-in hard drive, Smart Media Card (SMC), Secure Digital (SD) card, Flash Card, etc., provided on the control device. Furthermore, the memory may include both internal and external storage units of the control device. The memory is used to store the operating system, applications, bootloader, data, and other programs, such as the program code of computer programs. The memory can also be used to temporarily store data that has been output or will be output.

[0124] In applications, the communication module can be configured as any device capable of direct or indirect wired or wireless communication with other devices, depending on actual needs. For example, the communication module can provide solutions for communication on network devices, including communication interfaces such as Universal Serial Bus (USB), Local Area Networks (LAN), Wireless Local Area Networks (WLAN) (e.g., Wi-Fi), Bluetooth, Zigbee, mobile communication networks, Global Navigation Satellite System (GNSS), Frequency Modulation (FM), Near Field Communication (NFC), and Infrared (IR). The communication module can include an antenna, which can have a single element or be an antenna array with multiple elements. The communication module can receive electromagnetic waves through the antenna, frequency modulate and filter the electromagnetic wave signal, and send the processed signal to the processor. The communication module can also receive signals to be transmitted from the processor, frequency modulate and amplify them, and then convert them into electromagnetic waves for radiation via the antenna.

[0125] It should be noted that the information interaction and execution process between the above-mentioned devices / units are based on the same concept as the method embodiments of this application. For details on their specific functions and technical effects, please refer to the method embodiments section, and they will not be repeated here.

[0126] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units is merely an example. In practical applications, the above functions can be assigned to different functional units as needed, that is, the internal structure of the device can be divided into different functional units to complete all or part of the functions described above. The functional units in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit. Furthermore, the specific names of the functional units are only for easy differentiation and are not intended to limit the scope of protection of this application. The specific working process of the units in the above system can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0127] This application also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps of the dual optical frequency comb ranging method described above.

[0128] This application also provides a computer program product that, when run on a control device, causes the control device to execute the steps of the dual optical frequency comb ranging method described above.

[0129] This application also provides a dual optical frequency comb ranging system, which, based on the dual optical frequency comb ranging system in the above embodiments, further includes the control device in the above embodiments;

[0130] The control equipment is electrically connected to the first optical frequency comb, the second optical frequency comb, and the ranging equipment.

[0131] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the methods of the above embodiments of this application can be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable medium can include at least: any entity or device capable of carrying the computer program code to a control device, a recording medium, a computer memory, a read-only memory (ROM), a random access memory (RAM), an electrical carrier signal, a telecommunication signal, and a software distribution medium. Examples include USB flash drives, portable hard drives, magnetic disks, or optical disks.

[0132] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0133] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0134] In the embodiments provided in this application, it should be understood that the disclosed devices, control devices, and methods can be implemented by other methods. For example, the device and control device embodiments described above are merely illustrative. For instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, two or more units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

[0135] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A dual-frequency comb ranging system, characterized in that, It includes a first optical frequency comb, a second optical frequency comb, a circulator, a first coupler, and a second coupler; The first optical frequency comb is used to generate a ranging optical signal at a first repetition frequency. The ranging optical signal is transmitted to the first coupler via the circulator, and then split by the first coupler and transmitted to the reflector and the object under test for calibrating the reference position, respectively. The second optical frequency comb is used to generate a reference optical signal at a second repetition frequency, and the reference optical signal is transmitted to the second coupler; The first reflected light signal reflected by the mirror and the second reflected light signal reflected by the object under test are combined by the first coupler and then transmitted to the second coupler via the circulator. The reference optical signal, the first reflected optical signal, and the second reflected optical signal interfere in the second coupler to generate an interference optical signal that is transmitted to the ranging device. The ranging device is used to perform photoelectric conversion and low-pass filtering on the interference light signal to obtain the modulation envelope and acquire the time domain information of the modulation envelope, thereby obtaining the distance information of the object to be measured. Wherein, the second repetition frequency is the first repetition frequency. The second repetition frequency is times that of The difference between the first repetition frequency and the second repetition frequency is equal to the ranging rate of the dual-frequency comb ranging system, and at least one of the first repetition frequency and the second repetition frequency is adjustable. For decimals greater than 2, for The value after rounding down to the nearest integer.

2. The dual-frequency comb ranging system as described in claim 1, characterized in that, The wavelengths of the ranging optical signal and the reference optical signal include at least one of the ultraviolet band, visible light band, near-infrared band, and mid-infrared band.

3. The dual-frequency comb ranging system as described in claim 1, characterized in that, The first optical frequency comb and the second optical frequency comb are respectively one of a mode-locked laser optical frequency comb, an electro-optic modulation optical frequency comb, and a microcavity optical frequency comb.

4. The dual-frequency comb ranging system as described in claim 3, characterized in that, The mode-locked laser frequency comb is an erbium-doped fiber mode-locked laser frequency comb, a ytterbium-doped fiber mode-locked laser frequency comb, or a Ti:sapphire mode-locked laser frequency comb. The electro-optic modulated optical frequency comb is used to generate an optical frequency comb signal by phase modulation of a continuous optical signal using an external radio frequency signal. The microcavity optical frequency comb is a microring optical frequency comb, microsphere optical frequency comb, or microdisk optical frequency comb based on at least one of silicon, silicon dioxide, silicon nitride, lithium niobate, calcium fluoride, and magnesium fluoride.

5. A dual-frequency comb ranging method, characterized in that, Based on the dual-frequency comb ranging system according to any one of claims 1 to 4, the method includes: Obtain the user's input command for adjusting the repetition frequency; According to the repetition frequency adjustment command, at least one of the first repetition frequency and the second repetition frequency is adjusted to adjust the ranging rate.

6. The dual-frequency comb ranging method as described in claim 5, characterized in that, The method further includes: Based on the time-domain information, the modulation envelope delay is obtained; Based on the second repetition frequency and the ranging rate, the equivalent amplification factor of the first optical frequency comb and the second optical frequency comb is obtained; The distance to the object under test is obtained based on the modulation envelope delay and the equivalent amplification factor.

7. The dual-frequency comb ranging method as described in claim 6, characterized in that, The formula for calculating the ranging rate is: The formula for calculating the equivalent magnification is: The formula for calculating the distance is: in, This represents the first repetition frequency. This indicates the second repetition frequency. This indicates the ranging rate. This indicates the equivalent magnification factor. Indicates the distance, This represents the speed of light in a vacuum. This indicates the time delay between the first reflected light signal and the second reflected light signal. This indicates the modulation envelope delay.

8. A control device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the dual optical frequency comb ranging method according to any one of claims 5 to 7.

9. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the steps of the dual optical frequency comb ranging method according to any one of claims 5 to 7.

10. A dual-frequency comb ranging system, characterized in that, Based on the dual optical frequency comb ranging system according to any one of claims 1 to 4, it further includes the control device according to claim 8; The control device is electrically connected to the first optical frequency comb, the second optical frequency comb, and the ranging device, respectively, and the control device is used for: Control the first optical frequency comb to generate a ranging optical signal at a first repetition frequency; Control the second optical frequency comb to generate a reference optical signal at a second repetition frequency; Based on the time-domain information, the distance information of the object to be measured is obtained.

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