A high stable millimeter wave generation method and system

Abstract

The application discloses a high-stability millimeter wave generation method and system; wherein the method comprises the following steps: inputting a single-frequency laser and an optical microwave signal into an electro-optic phase modulator to modulate the single-frequency laser by using the optical microwave signal; filtering the modulated laser by using a preset filter device to obtain filtered laser; the filtered laser is a double-frequency signal composed of two target single-frequency signals in the frequency domain; and optoelectronically detecting the filtered laser to obtain millimeter waves with high frequency stability.

Description

[0001] The present application claims priority to the Chinese patent application with the application number of “202311579421.X” and the invention name of “A method and device for generating high-stability millimeter waves by light” filed on November 23, 2023, at the China Patent Office, the whole content of which is incorporated herein by reference. TECHNICAL FIELD

[0002] The present application belongs to the field of millimeter waves, and particularly relates to a method and system for generating high-stability millimeter waves. BACKGROUND

[0003] Millimeter waves have a very wide bandwidth. Under the same antenna size, the beam of millimeter waves is narrower than that of microwaves, millimeter waves have strong detection capability, good security and privacy, and compared with microwave band components, millimeter wave components are small in size, so millimeter wave systems are easier to miniaturize. Millimeter wave band has four atmospheric windows, and high-stability millimeter wave signals can be used in the field of high-speed and large-capacity wireless communication between space and ground. It can also be applied in the fields of 6G optical communication, millimeter wave time synchronization, millimeter wave radar, future medical treatment, etc.

[0004] In the prior art, a commonly used method for generating millimeter waves is the external modulator method. The principle of generating millimeter waves by the external modulator method is to use a microwave signal to modulate a carrier laser to generate a phase-related modulated signal, and then use a wavelength selection switch on the output side of the modulator to select the required sideband, and perform photoelectric detection on the selected sideband to obtain the required millimeter wave.

[0005] However, the selected sideband by the wavelength selection switch has large noise, resulting in poor frequency stability of the finally generated millimeter wave signal. SUMMARY

[0006] In order to solve the above problems existing in the prior art, the present application provides a method and system for generating high-stability millimeter waves.

[0007] The technical problem to be solved by the present application is solved by the following technical scheme:

[0008] A method for generating high-stability millimeter waves, comprising:

[0009] inputting a single-frequency laser and an optically generated microwave signal into an electro-optic phase modulator to modulate the single-frequency laser by the optically generated microwave signal;

[0010] filtering the modulated laser using a pre-set filter device to obtain filtered laser; wherein the filtered laser exhibits a double-frequency signal composed of two target single-frequency signals in the frequency domain;

[0011] photoelectrically detecting the filtered laser to obtain the required millimeter wave;

[0012] The filtering device comprises a first optical fiber collimator, a 1 / 2 wave plate, a polarization beam splitter prism, an etalon, a 1 / 4 wave plate, a mirror and a second optical fiber collimator;

[0013] The modulated laser light sequentially passes through the first optical fiber collimator, the 1 / 2 wave plate and the polarization beam splitter prism into the etalon for first filtering; the first filtered laser light is reflected by the mirror after passing through the 1 / 4 wave plate, and reenters the etalon for second filtering after passing through the 1 / 4 wave plate again; the second filtered laser light is totally reflected by the polarization beam splitter prism and is output through the second optical fiber collimator.

[0014] Optionally, the frequency of the light-generated microwave signal is 10 GHz, and the two target single-frequency signals are +5th order sideband and -5th order sideband in the filtered laser light.

[0015] The application further provides a high-stability millimeter wave generation system, comprising a laser generation device, a light-generated microwave device, an electro-optical phase modulator, a filtering device and a photoelectric detection device.

[0016] The laser generation device is used for generating single-frequency laser light.

[0017] The light-generated microwave device is used for generating a light-generated microwave signal.

[0018] The electro-optical phase modulator is used for modulating the single-frequency laser light by using the light-generated microwave signal.

[0019] The filtering device is used for filtering the modulated laser light to obtain filtered laser light; the filtered laser light is a double-frequency signal composed of two target single-frequency signals in the frequency domain.

[0020] The photoelectric detection device is used for photoelectrically detecting the filtered laser light to obtain the required millimeter wave.

[0021] The filtering device comprises a first optical fiber collimator, a 1 / 2 wave plate, a polarization beam splitter prism, an etalon, a 1 / 4 wave plate, a mirror and a second optical fiber collimator.

[0022] The modulated laser light sequentially passes through the first optical fiber collimator, the 1 / 2 wave plate and the polarization beam splitter prism into the etalon for first filtering; the first filtered laser light is reflected by the mirror after passing through the 1 / 4 wave plate, and reenters the etalon for second filtering after passing through the 1 / 4 wave plate again; the second filtered laser light is totally reflected by the polarization beam splitter prism and is output through the second optical fiber collimator.

[0023] Optionally, the light-generated microwave device comprises: a single-frequency ultra-stable laser generating device, a femtosecond pulse laser, a locking device, a photoelectric detector, a band-pass filter and a power amplifier.

[0024] The single-frequency ultra-stable laser generating device is configured to output single-frequency ultra-stable laser, and the femtosecond pulse laser is configured to output a femtosecond optical comb signal; the locking device is configured to lock one comb tooth of the femtosecond optical comb signal on the single-frequency ultra-stable laser and lock a carrier envelope phase shift frequency of the femtosecond optical comb signal, so as to obtain a femtosecond optical comb signal with ultra-stable laser frequency stability; the photoelectric detector is configured to detect the femtosecond optical comb signal with ultra-stable laser frequency stability, so as to obtain a detected microwave electrical signal; the band-pass filter is configured to perform band-pass filtering on the detected microwave electrical signal, so as to obtain a filtered microwave electrical signal; and the power amplifier is configured to amplify the filtered microwave electrical signal, so as to obtain the light-generated microwave signal.

[0025] In the high-stability millimeter wave generation method provided by the application, the single-frequency laser is modulated by the light-generated microwave signal, the modulated laser shows multiple single-frequency signals with the frequency interval of the frequency of the light-generated microwave signal in the frequency domain, and the frequency interval between the two target single-frequency signals with the highest amplitude in the multiple single-frequency signals is equal to f; f is the required millimeter wave frequency. Then, the modulated laser is filtered based on the etalon; since the transmission spectrum of the etalon shows multiple interval-arranged passbands with the free spectral range (FSR) as the frequency interval in the frequency domain, the application can effectively filter out the single-frequency signals between the two target single-frequency signals and the single-frequency signals outside the two target single-frequency signals by using the etalon with the center frequency and the frequency of the single-frequency laser being the same and the filtering bandwidth corresponding to the fineness being as small as possible, so as to extract the two target single-frequency signals from the multiple single-frequency signals at one time. Compared with the filtering mode using the wavelength selection switch in the prior art, the filtering effect is greatly improved, and the dual-frequency signal can be screened out at one time. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 is a flowchart of a high-stability millimeter wave generation method provided by an embodiment of the application;

[0027] Figure 2 is a structural schematic diagram of a light-generated microwave device provided in an embodiment of the application;

[0028] Figure 3 is a schematic diagram of generating a light-generated microwave signal in an embodiment of the application;

[0029] Figure 4 is a structural schematic diagram of another light-generated microwave device provided in an embodiment of the application;

[0030] Figure 5 is a structural schematic diagram of a high-stability millimeter wave generation system provided by an embodiment of the present application;

[0031] Figure 6 is a structural schematic diagram of a filtering device provided by an embodiment of the present application;

[0032] Figure 7 is an effect diagram of filtering the modulated laser light using a single F-P etalon;

[0033] Figure 8 is an effect diagram of filtering the modulated laser light using the filtering device shown in Figure 6 ;

[0034] Figure 9 exemplarily shows the frequency stability of a millimeter wave generated by the method of an embodiment of the present application;

[0035] Figure 10 is an additional frequency stability of the system for generating the millimeter wave in Figure 9 ; DETAILED DESCRIPTION

[0036] The present application will be further described in detail below with reference to specific embodiments, but the embodiments of the present application are not limited thereto.

[0037] In order to obtain a millimeter wave with higher frequency stability, an embodiment of the present application provides a high-stability millimeter wave generation method, as shown in Figure 1 , the method comprises the following steps:

[0038] S10, input a single-frequency laser light and an optical microwave signal to an electro-optical phase modulator to modulate the single-frequency ultra-stable laser light by the optical microwave signal.

[0039] As shown in Figure 5 , the single-frequency laser light is generated by a laser generation device 1, the laser generation device 1 comprises a single-frequency laser and a fiber amplifier, the single-frequency laser generates the single-frequency laser light, and the fiber amplifier (for example, erbium-doped fiber amplification) amplifies the single-frequency laser light to obtain the single-frequency laser light that can be input to the electro-optical phase modulator.

[0040] The optical microwave signal is generated by an optical microwave device 2. As shown in Figure 2 exemplarily, the optical microwave device 2 can comprise a single-frequency ultra-stable laser generation device, a femtosecond pulse laser, a locking device and a photoelectric detector.

[0041] The single-frequency ultra-stable laser generator is used to output a single-frequency ultra-stable laser, and the femtosecond pulse laser is used to output a femtosecond optical comb signal. The locking device is used to lock one tooth of the femtosecond optical comb signal onto the ultra-stable laser and lock the carrier envelope phase shift frequency of the femtosecond optical comb signal to obtain a femtosecond optical comb signal with ultra-stable laser frequency stability. The photodetector is used to detect the femtosecond optical comb signal with ultra-stable laser frequency stability to obtain a detection microwave signal. The frequency of the detection microwave signal is in the microwave band, so the detection microwave signal can be directly used as the photogenerated microwave signal input to the electro-optic phase modulator.

[0042] Specifically, in a single-frequency ultrastable laser generator, by locking the single-frequency laser onto an ultrastable cavity and using the ultrastable optical cavity as a frequency reference, a single-frequency ultrastable laser with ultrastable cavity length stability is obtained; then, a locking device locks a specific optical tooth of a femtosecond optical comb onto this single-frequency ultrastable laser, such as... Figure 3 As shown, the carrier envelope phase shift frequency of the femtosecond optical comb is simultaneously locked to obtain a comb frequency with ultra-stable laser frequency stability, i.e., a femtosecond optical comb signal with ultra-stable laser frequency stability. The locked femtosecond optical comb frequency inherits the frequency stability of the single-frequency ultra-stable laser. For the locking method of the optical frequency comb and the locking device used in conjunction with it, please refer to relevant prior art; this embodiment of the invention does not limit this. After generating the femtosecond optical comb signal with ultra-stable laser frequency stability, the repetition frequency of the femtosecond optical comb signal is detected by a low-noise photodetector. This allows the detection microwave signal with ultra-stable laser frequency stability to be detected, which can then be used as the photogenerated microwave signal input to the electro-optic phase modulator. Therefore, this embodiment of the invention uses a single-frequency ultra-stable laser as a frequency reference and transfers the frequency stability of the ultra-stable laser to the microwave band through a femtosecond optical comb to obtain a microwave signal with ultra-stable laser frequency stability.

[0043] In another implementation, such as Figure 4 As shown, the photoelectric microwave device 2 may include: a single-frequency ultra-stable laser generator, a femtosecond pulse laser, a locking device, a photodetector, a bandpass filter, and a power amplifier.

[0044] Among them, the single-frequency ultra-stable laser generating device, femtosecond pulse laser, locking device, and photodetector have the same function as the aforementioned photogenerated microwave device. The bandpass filter is used to perform bandpass filtering on the detection microwave electrical signal obtained by the photodetector to obtain the filtered microwave electrical signal. The power amplifier is used to amplify the filtered microwave electrical signal, so that the amplified microwave electrical signal is used as the photogenerated microwave signal input to the electro-optic phase modulator.

[0045] Here, the probe microwave electrical signal is filtered to filter out other repetition frequency components of the femtosecond optical comb, so as to improve the frequency stability of the optical microwave signal, and the filtered microwave electrical signal is amplified, so as to facilitate subsequent modulation of the single-frequency laser generated by the laser generating device 1. Moreover, the gain of the power amplifier can be adjusted to flexibly adjust the power of the optical microwave signal input to the electro-optical phase modulator.

[0046] Referring to Figure 5 The optical microwave signal with super-stable laser frequency stability and the single-frequency laser are input to the electro-optical phase modulator (EOM) 3, the single-frequency laser is modulated by using the optical microwave signal as a modulation signal, and the modulated laser generates a plurality of single-frequency signals in the frequency domain.

[0047] In the embodiment of the present application, in order to enable the modulated laser to generate more single-frequency signals in the frequency domain, the single-frequency laser can be over-modulated by adjusting the power of the optical microwave signal, and the greater the power of the optical microwave signal, the more the number of single-frequency signals of the modulated signal output by the electro-optical phase modulator 3 in the frequency domain.

[0048] In addition, in order to support over-modulation, the modulation power of the electro-optical phase modulator 3 used in the embodiment of the present application needs to be greater than 1W, that is, the electro-optical phase modulator used in the embodiment of the present application has high modulation power (i.e. low half-wave voltage). Preferably, in order to obtain better modulation effect, the modulation power of the electro-optical phase modulator 3 is not less than 2W.

[0049] In practice, the modulated laser appears as a plurality of single-frequency signals with the frequency of the optical microwave signal as the frequency interval in the frequency domain, and the frequency interval between the two target single-frequency signals with the highest amplitude in the plurality of single-frequency signals is equal to f; f is the required millimeter wave frequency.

[0050] Specifically, the power of the optical microwave signal input to the electro-optical phase modulator 3 is continuously adjusted, and the spectrum of the modulated laser output by the electro-optical phase modulator 3 is observed at the same time, so that the number of modulation sidebands is greater than the number of required sidebands, and when the frequency interval between two sidebands in the spectrum is equal to the required millimeter wave frequency, and their amplitudes show the highest trend among all modulation sidebands, the modulation purpose is achieved, and the two sidebands are the required two target single-frequency signals. Since the microwave signal has super-stable laser frequency stability, the modulated signal can have super-stable laser frequency stability by using the microwave signal as a modulation signal.

[0051] S20, filtering the modulated laser using a preset filter device to obtain filtered laser; the filtered laser appears as a double-frequency signal composed of two target single-frequency signals in the frequency domain.

[0052] Specifically, by customizing the FP etalon to match its center frequency with the frequency of the single-frequency laser, it can be matched with the mid-frequency of two target single-frequency signals. Furthermore, the filter bandwidth corresponding to the FP etalon's precision is made as small as possible, less than half the frequency interval between the two target single-frequency signals. This allows for the effective filtering of single-frequency signals between and outside the two target single-frequency signals from multiple single-frequency signals, thus enabling the selection of two target single-frequency signals at once. The filter bandwidth corresponding to the precision of the FP etalon is approximately equal to the FP etalon's free spectral range divided by its precision; therefore, the higher the precision of the FP etalon, the narrower its filter bandwidth. For example, if f equals 100 GHz and the modulation signal frequency is 10 GHz, then the filter bandwidth of the FP etalon should be as small as possible, ideally less than 5 GHz.

[0053] like Figure 7 As shown, the green spectral line is the spectrum of the modulated laser, and the blue spectral line is the transmission output spectrum after filtering the modulated laser using a single FP etalon. The two highest peaks are the two target single-frequency signals. In this embodiment of the invention, the +5th order sideband and -5th order sideband single-frequency signals are selected as the target single-frequency signals. The center frequency of the FP etalon is exactly located between the +5th order and -5th order single-frequency signals (that is, the frequency of the modulated single-frequency laser). The filtering bandwidth corresponding to the precision of the FP etalon is just enough to allow a single target single-frequency signal to pass through.

[0054] In the process of realizing this invention, the inventors discovered that although using a single FP etalon to filter the modulated laser can filter out single-frequency signals between and outside of two target single-frequency signals from multiple single-frequency signals, if the precision of the single FP etalon is insufficient, it may also lead to the presence of undesired single-frequency signals near the target single-frequency signal, thereby affecting the frequency stability of the final generated millimeter wave. For example, there may be single-frequency signals with a certain power of +4th and +6th order sidebands next to the target single-frequency signal with the selected +5th order sideband, and single-frequency signals with a certain power of -4th and -6th order sidebands next to the target single-frequency signal with the selected -5th order sideband.

[0055] While the aforementioned problems can be addressed by optimizing the precision of individual FP etalons, high-precision FP etalons place stringent requirements on the optical path, are expensive, and are not conducive to engineering. To solve this problem, embodiments of the present invention utilize, as follows: Figure 6 The filtering device shown filters the modulated laser.

[0056] like Figure 6As shown, the filtering device comprises: a first fiber collimator, a 1 / 2 wave plate, a polarization beam splitter prism, an F-P standard device, a 1 / 4 wave plate, a mirror and a second fiber collimator; wherein the modulated laser light sequentially passes through the first fiber collimator, the 1 / 2 wave plate and the polarization beam splitter prism to enter the F-P standard device for first filtering; the laser light after the first filtering is reflected by the mirror after passing through the 1 / 4 wave plate, and reenters the F-P standard device for second filtering after passing through the 1 / 4 wave plate again; the laser light after the second filtering is totally reflected by the polarization beam splitter prism and is output through the second fiber collimator.

[0057] Wherein, the laser light from the first fiber collimator enters the 1 / 2 wave plate to rotate into horizontal polarized light, is totally transmitted through the polarization beam splitter prism, and is normally incident into the F-P standard device for first filtering; the laser light from the F-P standard device is reflected into the F-P standard device through the mirror for second filtering, and the laser light entering the F-P standard device is vertical polarized light due to twice passing through the 1 / 4 wave plate, so that the laser light is totally reflected by the polarization beam splitter prism after being output from the F-P standard device and enters the second fiber collimator, and the other end of the second fiber collimator can be connected with an optical fiber, so that the laser light after the second filtering is output through the optical fiber, and the filtering is completed.

[0058] In the embodiment of the application, the modulated laser light passes through the F-P standard device twice, which is equivalent to improving the fineness of a single F-P standard device, so that the two target single frequency signals and the single frequency signals outside them are further suppressed, and the filtering effect is improved. Figure 6 In the figure, the green line represents the double frequency signal obtained by using a single F-P standard device to filter the modulated laser light, and the yellow line represents the double frequency signal obtained by using the above filtering device to filter the modulated laser light.

[0059] Figure 8 The filtering device is used to filter the modulated laser light. Figure 6 The filtering effect of the filtering device on the modulated laser light is shown in the figure, wherein the black spectrum line is the spectrum of the modulated laser light, and the red spectrum line is the transmission output spectrum of the modulated laser light after being filtered by the filtering device. Figure 7 It can be seen that the filtering effect is greatly improved by using the filtering device to filter the modulated laser light, and the cost of the first fiber collimator, the 1 / 2 wave plate, the polarization beam splitter prism, the 1 / 4 wave plate, the mirror and the second fiber collimator is low, and they can be mass-produced, so that the cost can be effectively reduced.

[0060] S30, photoelectrically detecting the filtered laser light to obtain the required millimeter wave.

[0061] Here, photoelectric detection of the filtered laser is achieved by a photoelectric detection device, which can be a photoelectric detector or a untraveling carrier (UTC) photoelectric mixer, and is not limited thereto. It should be noted that the bandwidth of the photoelectric detection device is greater than the millimeter wave frequency. Thus, by photoelectric detection of the filtered laser, the super-stable light generates a microwave signal, which is multiplied to the millimeter wave band with low additional noise, i.e., a millimeter wave with the frequency stability of the super-stable laser is obtained.

[0062] The high-stability millimeter wave generation method of the embodiment of the present application modulates the single-frequency laser with the light-generated microwave signal, and filters the modulated laser based on the F-P etalon. Since the free spectral range (FSR) of the F-P etalon is a plurality of interval-arranged passbands, by customizing the F-P etalon, the center frequency of which is the same as that of the single-frequency laser, and the precision of which corresponds to a bandwidth much smaller than half of the frequency interval (for example, 10 GHz) of the two target single-frequency signals, the F-P etalon can effectively filter out the single-frequency signals between and outside the two target single-frequency signals from a plurality of single-frequency signals, so as to screen the two target single-frequency signals from the plurality of single-frequency signals. Compared with the prior art of using a wavelength selection switch to achieve filtering, the filtering effect is greatly improved, and the dual-frequency signal can be screened at one time.

[0063] The high-stability millimeter wave generation method of the embodiment of the present application generates millimeter waves by using the optical frequency multiplication technology. Compared with the prior art of using a multi-step electrical frequency multiplication method, the millimeter waves generated by the embodiment of the present application have higher frequency stability and lower phase noise, and the number of devices used is small, which is easy to integrate and can be more widely applied in high-stability low-noise frequency multiplication systems, such as millimeter wave radar systems, to improve the test accuracy of the radar; and in terahertz communication, to improve the communication capacity and communication rate.

[0064] In a specific example, a high-stability millimeter wave generation system is built based on the related components mentioned in the above high-stability millimeter wave generation method. The system generates a single-frequency laser with a wavelength of 1556 nm and a power of 16 mW by using a single-frequency laser, and amplifies it to 200 mW by an erbium-doped fiber amplifier. Figure 4 The light-generated microwave device shown in the figure generates a light-generated microwave signal with a frequency of 10 GHz, which is amplified to about 1 W by a microwave power amplifier. Then, the 200 mW single-frequency laser and the 1 W light-generated microwave signal are input to the electro-optical phase modulation to generate modulated laser, which includes a plurality of single-frequency signals in the frequency domain. The modulated laser is filtered by the F-P etalon to obtain a dual-frequency signal with a frequency of 20 GHz. Figure 6The filter device shown filters to obtain filtered laser containing +5th order and -5th order sidebands in the frequency domain. Then, the filtered laser is optoelectronically detected by using a single row carrier (UTC) photomixer with a bandwidth of 110GHz, so that a millimeter wave with high frequency stability of 100GHz is obtained. The frequency stability of the millimeter wave is tested, and the test result is as shown in Figure 9 As shown, the frequency stability of the millimeter wave generated by using the system can reach 5.2*10 -15 @1s order of magnitude, and the frequency stability of 100 seconds reaches 2.1*10 -15 .

[0065] In addition, the inventors also test the additional frequency stability of the system. The specific test method comprises the following steps: a same system is copied, the 10GHz optical microwave signal is divided into two paths by using an electric power divider and is sent into the two systems respectively, the filtered laser in the two systems is mixed and then the frequency stability is tested, and the measured frequency stability is divided by to obtain the additional frequency stability of a single system. The test result is as shown in Figure 10 As shown, the additional frequency stability of the system reaches 2.3*10 -15 @1s, the frequency stability of 100 seconds reaches 5.1*10 -16 , and the frequency stability at 8192 seconds reduces to 1.6*10 -17 .

[0066] Based on the test results of Figure 9 and Figure 10 , it can be known that, on the basis of using the optical microwave signal with the super-stable laser frequency stability as the modulation signal, and in cooperation with the system with the additional frequency stability comparable to or even higher than the super-stable laser frequency stability, the modulated laser can have the super-stable laser frequency stability.

[0067] Based on the same inventive concept, the embodiment of the present application also provides a high-stability millimeter wave generation system, as shown in Figure 5 , comprising: a laser generation device 1, an optical microwave device 2, an electro-optical phase modulator 3, a filter device 4 and an optoelectronic detection device 5.

[0068] The laser generation device 1 is used to generate single-frequency laser.

[0069] The optical microwave device 2 is used to generate an optical microwave signal.

[0070] The electro-optical phase modulator 3 is used to modulate the single-frequency laser by using the optical microwave signal.

[0071] The filter device 4 is used for filtering the modulated laser to obtain filtered laser; wherein the filtered laser is expressed as a double-frequency signal composed of two target single-frequency signals in a frequency domain.

[0072] The photoelectric detection device 5 is used for photoelectrically detecting the filtered laser to obtain the required millimeter wave.

[0073] Referring to Figure 6 , the filter device 4 comprises a first optical fiber collimator, a 1 / 2 wave plate, a polarization beam splitter prism, a standard device (F-P standard device), a 1 / 4 wave plate, a mirror and a second optical fiber collimator.

[0074] The modulated laser sequentially passes through the first optical fiber collimator, the 1 / 2 wave plate and the polarization beam splitter prism to enter the F-P standard device to perform first filtering; the laser filtered for the first time passes through the 1 / 4 wave plate and is reflected by the mirror, and then passes through the 1 / 4 wave plate again to re-enter the F-P standard device to perform second filtering; the laser filtered for the second time is totally reflected by the polarization beam splitter prism and is output through the second optical fiber collimator.

[0075] In an embodiment, referring to Figure 4 , the light-generated microwave device 2 comprises a single-frequency ultra-stable laser generating device, a femtosecond pulse laser, a locking device, a photoelectric detector, a band-pass filter and a power amplifier.

[0076] The single-frequency ultra-stable laser generating device is used for outputting single-frequency ultra-stable laser, the femtosecond pulse laser is used for outputting a femtosecond optical comb signal; the locking device is used for locking one comb tooth of the femtosecond optical comb signal on the single-frequency ultra-stable laser and locking a carrier envelope phase shift frequency of the femtosecond optical comb to obtain a femtosecond optical comb signal with ultra-stable laser frequency stability; the photoelectric detector is used for detecting the femtosecond optical comb signal with ultra-stable laser frequency stability to obtain a detected microwave electrical signal; the band-pass filter is used for band-pass filtering the detected microwave electrical signal to obtain a filtered microwave electrical signal; and the power amplifier is used for amplifying the filtered microwave electrical signal to obtain the above-mentioned light-generated microwave signal.

[0077] In an embodiment, the power of the light-generated microwave signal input to the electro-optical phase modulator 3 can be adjusted by adjusting the gain of the power amplifier.

[0078] The system provided by the embodiment of the application can be used in a ground-based time service system, cooperates with a fiber time service system, constructs a fiber millimeter wave communication network, and realizes stereoscopic, dead-angle-free time service and communication network through the combination of wireless communication and wired fiber communication.

[0079] The system provided by the embodiment of the application can be applied to the field of terahertz communication to improve channel capacity and rate, applied to space communication to improve air-ground communication rate and communication capacity, applied to high-precision millimeter wave radar to improve the detection precision and the number of detected targets of the radar, and combined with a high-precision ground-based timing system to realize optical wireless communication by carrying an optical fiber timing network, and realize omnidirectional and stereoscopic timing.

[0080] It should be noted that, for the system embodiment, the components involved have been illustrated in the method embodiment, and therefore the description is relatively simple, and the relevant parts can be referred to the part of the method embodiment.

[0081] It should be noted that the terms "first", "second", and the like are used to distinguish similar objects, and do not necessarily have to be used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances, so that the embodiments of the application described herein can be implemented in an order other than those illustrated or described herein. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. Rather, they are merely examples of devices and methods consistent with some aspects of the present application.

[0082] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in the present specification.

[0083] Although the present application is described herein in conjunction with various embodiments, other variations of the disclosed embodiments can be understood and implemented by those skilled in the art with reference to the drawings and the disclosure. In the description of the present application, the word "comprising" does not exclude other components or steps, "one" or "an" does not exclude a plurality, and "plurality" means two or more, unless otherwise explicitly specified. In addition, some measures are described in different embodiments, but this does not mean that these measures cannot be combined to produce good results.

[0084] For device / electronic device / storage medium embodiments, since they are basically similar to the method embodiments, the description is relatively simple, and the relevant parts can be referred to the part of the method embodiment.

[0085] The above is further detailed description of the present application in combination with specific preferred embodiments, and cannot be deemed as limitation of the specific implementation of the present application to these descriptions. For those skilled in the art to which the present application belongs, without departing from the concept of the present application, a number of simple deductions or substitutions can be made, and all of them shall be deemed as falling within the protection scope of the present application.

Claims

1. A method for high stable millimeter wave generation, characterized by, The application relates to a method for generating a millimeter wave signal. The method comprises the following steps: a single-frequency ultra-stable laser is generated by using a single-frequency ultra-stable laser generation device; a femtosecond optical comb signal is output by using a femtosecond pulse laser; one tooth of the femtosecond optical comb signal is locked on the single-frequency ultra-stable laser by using a locking device, and a carrier envelope phase shift frequency of the femtosecond optical comb signal is locked, so that a femtosecond optical comb signal with ultra-stable laser frequency stability is obtained; a detection microwave electric signal is obtained by detecting the femtosecond optical comb signal with ultra-stable laser frequency stability by using a photoelectric detector; a band-pass filter is used to perform band-pass filtering on the detection microwave electric signal, so that a filtered microwave electric signal is obtained; the filtered microwave electric signal is amplified by using a power amplifier, so that an optical microwave signal is obtained; a single-frequency laser and the optical microwave signal are input into an electro-optic phase modulator, so that the single-frequency laser is modulated by using the optical microwave signal; a preset filter device is used to filter the modulated laser, so that filtered laser is obtained; the filtered laser is composed of two target single-frequency signals in the frequency domain; the filter device comprises a first optical fiber collimator, a 1 / 2 wave plate, a polarization beam splitter prism, a standard device, a 1 / 4 wave plate, a mirror and a second optical fiber collimator; the modulated laser sequentially passes through the first optical fiber collimator, the 1 / 2 wave plate and the polarization beam splitter prism, enters the standard device to perform first filtering, the laser after the first filtering passes through the 1 / 4 wave plate, is reflected by the mirror, passes through the 1 / 4 wave plate again and reenters the standard device to perform second filtering, and the laser after the second filtering is totally reflected by the polarization beam splitter prism and is output through the second optical fiber collimator; 2. The method of claim 1, wherein, the filtered laser is photoelectrically detected, so that a required millimeter wave signal is obtained.

3. A high stability millimeter wave generation system, characterized by, The frequency of the optical microwave signal is 10 GHz, and the two target single-frequency signals are +5th-order sidebands and -5th-order sidebands in the filtered laser. The application relates to a method for generating a millimeter wave signal. The method comprises the following steps: a laser generation device, an optical microwave device, an electro-optic phase modulator, a filter device and a photoelectric detection device are provided; the laser generation device is used to generate a single-frequency laser; the optical microwave device is used to generate an optical microwave signal; the electro-optic phase modulator is used to modulate the single-frequency laser by using the optical microwave signal; the filter device is used to filter the modulated laser, so that filtered laser is obtained; the filtered laser is composed of two target single-frequency signals in the frequency domain; the filter device comprises a first optical fiber collimator, a 1 / 2 wave plate, a polarization beam splitter prism, a standard device, a 1 / 4 wave plate, a mirror and a second optical fiber collimator; the modulated laser sequentially passes through the first optical fiber collimator, the 1 / 2 wave plate and the polarization beam splitter prism, enters the standard device to perform first filtering, the laser after the first filtering passes through the 1 / 4 wave plate, is reflected by the mirror, passes through the 1 / 4 wave plate again and reenters the standard device to perform second filtering, and the laser after the second filtering is totally reflected by the polarization beam splitter prism and is output through the second optical fiber collimator. The photoelectric detection device is used for photoelectric detection of the filtered laser to obtain the required millimeter wave; The light-generated microwave device comprises a single-frequency ultra-stable laser generating device, a femtosecond pulse laser, a locking device, a photoelectric detector, a band-pass filter and a power amplifier. The single-frequency ultra-stable laser generating device is used for outputting single-frequency ultra-stable laser, and the femtosecond pulse laser is used for outputting a femtosecond optical comb signal; the locking device is used for locking one comb tooth of the femtosecond optical comb signal on the single-frequency ultra-stable laser and locking a carrier envelope phase shift frequency of the femtosecond optical comb signal to obtain a femtosecond optical comb signal with ultra-stable laser frequency stability; the photoelectric detector is used for detecting the femtosecond optical comb signal with ultra-stable laser frequency stability to obtain a detected microwave electrical signal; the band-pass filter is used for band-pass filtering the detected microwave electrical signal to obtain a filtered microwave electrical signal; and the power amplifier is used for amplifying the filtered microwave electrical signal to obtain the light-generated microwave signal.

Images