A tunable millimeter wave frequency generation device

Abstract

The present specification discloses a tunable millimeter wave frequency generating device, relates to the field of microwave technology, and aims to solve the problem of poor phase noise performance of millimeter wave signals obtained by existing frequency multiplication technology.The device comprises an optical frequency comb locking loop and a millimeter wave generating link;the optical frequency comb locking loop comprises an optical frequency comb, an optical beam splitter, a first photodetector, a first filter, a frequency mixer, an acoustic whispering gallery mode oscillator and a phase-locked amplifier; and the millimeter wave generating link comprises a second photodetector, a second filter and a millimeter wave amplifier.The millimeter wave signal generated by the device is tunable, and the phase noise performance of the millimeter wave signal can be effectively improved.

Description

Technical Field

[0001] This document relates to the field of microwave technology, and in particular to a tunable millimeter-wave frequency generating device. Background Technology

[0002] Millimeter waves typically refer to electromagnetic waves with frequencies between 30 and 300 GHz. They fall within the wavelength range where microwaves and far-infrared waves overlap, exhibiting characteristics of both spectra. Millimeter waves have important applications in fields such as communications, radar, spectroscopy, and radio astronomy.

[0003] In applications such as radar and radio astronomy, there are requirements for the phase noise and short-term frequency stability of millimeter waves. In existing technologies, in order to obtain millimeter waves with low phase noise, a method is usually adopted to synthesize low-noise microwave signals and then multiply the low-noise microwave signals by frequency doubling technology to obtain low-phase-noise millimeter wave signals.

[0004] However, the phase noise performance of millimeter-wave signals obtained using frequency doubling technology will deteriorate. Summary of the Invention

[0005] This specification provides a tunable millimeter-wave frequency generation device to solve the problem of poor phase noise performance of millimeter-wave signals obtained by existing frequency doubling techniques. The device includes an optical frequency comb locking loop and a millimeter-wave generation link.

[0006] The optical frequency comb locking loop includes an optical frequency comb, an optical beam splitter, a first signal acquisition device, and a frequency tunable device; the first output terminal of the optical beam splitter is connected to the first signal acquisition device.

[0007] The laser emitted by the optical frequency comb is split by the optical beam splitter, and the first signal acquisition device performs photoelectric conversion on the received laser signal to obtain a first microwave signal.

[0008] The tunable device is used to output an adjustable frequency signal, mix the adjustable frequency signal with the first microwave signal, and input it into the optical frequency comb.

[0009] The millimeter-wave generation link is connected to the second output terminal of the optical beam splitter and is used to output millimeter-wave frequency signals.

[0010] In some preferred embodiments, the first signal acquisition device includes a first photodetector and a first filter;

[0011] The input terminal of the first photodetector is connected to the first output terminal of the optical beam splitter;

[0012] The output terminal of the first photodetector is connected to the input terminal of the first filter.

[0013] In some preferred embodiments, the frequency-tunable device includes a mixer, a lock-in amplifier, and a whispering-gallery mode oscillator;

[0014] One input terminal of the mixer is connected to the output terminal of the first filter, and the other input terminal is connected to the whispering-gallery mode oscillator; the output terminal of the mixer is connected to the lock-in amplifier.

[0015] The output of the lock-in amplifier is connected to the optical frequency comb.

[0016] In some preferred embodiments, the millimeter-wave generation link includes a second photodetector and a second filter;

[0017] The input terminal of the second photodetector is connected to the second output terminal of the optical beam splitter;

[0018] The output terminal of the second photodetector is connected to the input terminal of the second filter.

[0019] In some preferred embodiments, the millimeter wave generation link further includes a millimeter wave amplifier;

[0020] The input terminal of the millimeter-wave amplifier is connected to the output terminal of the second filter.

[0021] In some preferred embodiments, the frequency of the optical frequency comb teeth is f, which is calculated as follows:

[0022] f = f0 + nf rep ;

[0023] Where f0 is the frequency of the initial comb teeth, f rep is the repetition frequency, and n is the number of comb tooth intervals.

[0024] In some preferred embodiments, the output frequency range of the first photodetector includes the center frequency of the first filter;

[0025] The output signal of the first photodetector is a plurality of microwave frequency signals with a set frequency interval.

[0026] In some preferred embodiments, the output frequency of the whispering-gallery mode oscillator is the same as the center frequency of the first filter.

[0027] In some preferred embodiments, the process by which the optical frequency comb locking loop performs millimeter-wave frequency tunability on the tunable millimeter-wave frequency generating device is as follows:

[0028] The adjustable frequency signal is mixed with the first microwave signal, and the mixed signal is then separated by the lock-in amplifier. The separated signal is input to the optical frequency comb to provide feedback control over the f0 and f1 of the optical frequency comb. rep That is, by adjusting the output frequency of the whispering-gallery mode oscillator, f0 and f are achieved. rep The frequency is adjustable.

[0029] In some preferred embodiments, the output frequency coverage of the second photodetector is greater than that of the first photodetector.

[0030] The above-described at least one technical solution adopted in the embodiments of this specification can achieve the following beneficial effects:

[0031] The millimeter-wave signal generated by this invention is tunable and can effectively improve its phase noise performance.

[0032] This invention locks the frequency of a certain tooth of an optical frequency comb onto a whispering-gallery mode oscillator, and uses the higher harmonics of the optical frequency comb to obtain low-phase-noise millimeter waves through photoelectric conversion. By adjusting the output frequency of the whispering-gallery mode oscillator, the millimeter-wave frequency can be tunable. This invention achieves frequency extension from the microwave band to the millimeter-wave band through optical means, while retaining the advantage of low phase noise. Attached Figure Description

[0033] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0034] Figure 1 A schematic diagram of a tunable millimeter-wave frequency generating device provided in one embodiment of this specification;

[0035] Figure label:

[0036] 1: Optical frequency comb;

[0037] 2: Optical beam splitter;

[0038] 3: First photodetector;

[0039] 4: First filter;

[0040] 5: Mixer;

[0041] 6: Whispering-gallery mode oscillator;

[0042] 7: Lock-in amplifier;

[0043] 8: Second photodetector;

[0044] 9: Second filter;

[0045] 10: Millimeter-wave amplifier. Detailed Implementation

[0046] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0047] like Figure 1 The diagram shown is a structural schematic of a tunable millimeter-wave frequency generation device provided in an embodiment of the present invention. Specifically, the device includes an optical frequency comb locking loop and a millimeter-wave generation link.

[0048] The optical frequency comb locking loop includes an optical frequency comb, an optical beam splitter, a first signal acquisition device, and a frequency tunable device; the first output terminal of the optical beam splitter is connected to the first signal acquisition device.

[0049] The laser emitted by the optical frequency comb is split by the optical beam splitter, and the first signal acquisition device performs photoelectric conversion on the received laser signal to obtain a first microwave signal.

[0050] The tunable device is used to output an adjustable frequency signal, mix the adjustable frequency signal with the first microwave signal, and input it into the optical frequency comb.

[0051] The millimeter-wave generation link is connected to the second output terminal of the optical beam splitter and is used to output millimeter-wave frequency signals.

[0052] In this embodiment, a 1550nm optical beam splitter is preferred, and the splitting ratio is preferably 5:5.

[0053] The first signal acquisition device includes a first photodetector and a first filter; the input end of the first photodetector is connected to the first output end of the optical beam splitter; the output end of the first photodetector is connected to the input end of the first filter.

[0054] The frequency-tunable device includes a mixer, a lock-in amplifier, and a sound-gallery mode oscillator; one input terminal of the mixer is connected to the output terminal of the first filter, and the other input terminal is connected to the sound-gallery mode oscillator; the output terminal of the mixer is connected to the lock-in amplifier; and the output terminal of the lock-in amplifier is connected to the optical frequency comb.

[0055] The millimeter-wave generation link includes a second photodetector and a second filter; the input end of the second photodetector is connected to the second output end of the optical beam splitter; the output end of the second photodetector is connected to the input end of the second filter.

[0056] The millimeter-wave generation link also includes a millimeter-wave amplifier; the input of the millimeter-wave amplifier is connected to the output of the second filter.

[0057] The frequency of the optical frequency comb teeth is f, and its calculation method is as follows:

[0058] f = f0 + nf rep ;

[0059] Where f0 is the frequency of the initial comb teeth, f rep is the repetition frequency, and n is the number of comb tooth intervals.

[0060] In this embodiment, the output wavelength of the optical frequency comb is preferably 1550 nm. rep The preferred frequency is 250MHz.

[0061] The output frequency coverage of the first photodetector includes the center frequency of the first filter; the output signal of the first photodetector is a plurality of microwave frequency signals with a set frequency interval.

[0062] In this embodiment, the output frequency coverage of the first photodetector is preferably 10 GHz, and the set frequency interval is preferably 250 MHz; the center frequency of the first filter is preferably 10 GHz, and its output frequency is preferably a microwave signal of 10 GHz.

[0063] The output frequency of the whispering-gallery mode oscillator is the same as the center frequency of the first filter.

[0064] In this embodiment, the output frequency of the whispering-gallery mode oscillator is preferably adjusted to 10 GHz.

[0065] The process by which the optical frequency comb locking loop enables millimeter-wave frequency tuning of the tunable millimeter-wave frequency generating device is as follows:

[0066] The adjustable frequency signal is mixed with the first microwave signal, and the mixed signal is then separated by the lock-in amplifier. The separated signal is input to the optical frequency comb to provide feedback control over the f0 and f1 of the optical frequency comb. rep That is, by adjusting the output frequency of the whispering-gallery mode oscillator, f0 and f are achieved. rep The frequency is adjustable.

[0067] The output frequency coverage range of the second photodetector is greater than that of the first photodetector.

[0068] In this embodiment, the output frequency of the second photodetector preferably covers 100 GHz. The center frequency of the second filter and the operating frequency band of the millimeter-wave amplifier are selected according to the required millimeter-wave frequency, and the final output is a millimeter-wave of 30 to 100 GHz. By adjusting the output frequency of the whispering-gallery mode oscillator, the millimeter-wave output frequency can be tunable, and the phase noise index is excellent.

[0069] The above description is merely an embodiment of this application and is not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A tunable millimeter-wave frequency generating device, characterized in that, This includes optical frequency comb locking loops and millimeter-wave generation links; The optical frequency comb locking loop includes an optical frequency comb, an optical beam splitter, a first signal acquisition device, and a frequency tunable device; the first output terminal of the optical beam splitter is connected to the first signal acquisition device. The first signal acquisition device includes a first photodetector and a first filter; the input end of the first photodetector is connected to the first output end of the optical beam splitter; the output end of the first photodetector is connected to the input end of the first filter. The frequency-tunable device includes a mixer, a lock-in amplifier, and a whispering-gallery mode oscillator; one input terminal of the mixer is connected to the output terminal of the first filter, and the other input terminal is connected to the whispering-gallery mode oscillator; the output terminal of the mixer is connected to the lock-in amplifier; the output terminal of the lock-in amplifier is connected to the optical frequency comb. The laser emitted by the optical frequency comb is split by the optical beam splitter, and the first signal acquisition device performs photoelectric conversion on the received laser signal to obtain a first microwave signal. The tunable device is used to output an adjustable frequency signal, mix the adjustable frequency signal with the first microwave signal, and input it into the optical frequency comb. The millimeter-wave generation link is connected to the second output terminal of the optical beam splitter and is used to output millimeter-wave frequency signals.

2. The tunable millimeter-wave frequency generating device according to claim 1, characterized in that, The millimeter-wave generation link includes a second photodetector and a second filter; The input terminal of the second photodetector is connected to the second output terminal of the optical beam splitter; The output terminal of the second photodetector is connected to the input terminal of the second filter.

3. The tunable millimeter-wave frequency generating device according to claim 2, characterized in that, The millimeter wave generation link also includes a millimeter wave amplifier; The input terminal of the millimeter-wave amplifier is connected to the output terminal of the second filter.

4. The tunable millimeter-wave frequency generating device according to claim 1, characterized in that, The frequency of the optical frequency comb teeth is f, and its calculation method is as follows: f = f0 + nfrep; Where f0 is the frequency of the initial comb teeth, frep is the repetition frequency, and n is the number of comb tooth intervals.

5. The tunable millimeter-wave frequency generating device according to claim 1, characterized in that, The output frequency range of the first photodetector includes the center frequency of the first filter; The output signal of the first photodetector is a plurality of microwave frequency signals with a set frequency interval.

6. The tunable millimeter-wave frequency generating device according to claim 5, characterized in that, The output frequency of the whispering-gallery mode oscillator is the same as the center frequency of the first filter.

7. The tunable millimeter-wave frequency generating device according to claim 4, characterized in that, The process by which the optical frequency comb locking loop enables millimeter-wave frequency tuning of the tunable millimeter-wave frequency generating device is as follows: The adjustable frequency signal is mixed with the first microwave signal, and the mixed signal is separated by the lock-in amplifier. The separated signal is input to the optical frequency comb to control the f0 and frep of the optical frequency comb.

8. The tunable millimeter-wave frequency generating device according to claim 2, characterized in that, The output frequency coverage range of the second photodetector is greater than that of the first photodetector.

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