Electro-optical frequency comb generation device and method, light source, electronic device

Abstract

Embodiments of the present application provide an electro-optical frequency comb generating device and method, a light source and an electronic device, which relate to the technical field of electro-optical frequency comb. The electro-optical frequency comb generating device comprises a continuous laser, an electro-optical modulation device, a microwave source, a first interferometer, a first light detector, a microcontroller and a phase shift circuit. The input end of the electro-optical modulation device is connected to the output end of the continuous laser, the output end of the electro-optical modulation device is connected to the output end of the electro-optical frequency comb generating device and the first interferometer, the first light detector is connected to the first interferometer and the microcontroller, and the phase shift circuit is connected to the microwave source, the electro-optical modulation device and the microcontroller. The electro-optical frequency comb generating device can generate an electro-optical frequency comb with a wide spectrum and high flatness.

Description

Technical Field

[0001] This application relates to the field of electro-optic frequency comb technology, and in particular to an electro-optic frequency comb generating device and method, a light source, and electronic equipment. Background Technology

[0002] An optical frequency comb is a spectrum composed of a series of equally spaced frequency components with a coherent and stable phase relationship. It has important applications in fields such as precision spectroscopy and optical communication technology.

[0003] An electro-optic frequency comb (EOC) is an optical frequency comb generated using electro-optic modulation technology. Its core characteristics include flatness and spectral width, which directly determine its performance in applications such as spectral analysis, optical communication, and precision measurement. To broaden the spectral width and improve the spectral flatness of the EOC, the EOC generator typically cascades multiple modulators at the laser output (usually used to modulate the phase and intensity of the optical signal output from the continuous-wave laser). These modulators are driven by the same microwave source. When the microwave signals loaded onto all modulators are in phase, the EOC generated after modulation of the optical signal output from the continuous-wave laser by each stage of modulators is the widest and flattest. However, the presence of uncertain optical phase delays in the cascaded modulators and the uncertain microwave phase delays in the microwave signals loaded onto all modulators affect the output performance of the EOC.

[0004] A common practice is to use a phase shifter between the microwave source and the modulator to adjust the phase of the microwave signal applied to each modulator, thereby maintaining microwave signal synchronization. However, environmental disturbances in the microwave link can still cause inconsistencies in the phase of the microwave signal applied to each modulator, thus affecting the flatness and spectral performance of the electro-optic comb. Summary of the Invention

[0005] The embodiments of this application provide an electro-optic frequency comb generating device and method, a light source, and an electronic device, which can generate an electro-optic frequency comb with high flatness and wide spectral performance.

[0006] In a first aspect, embodiments of this application provide an electro-optic frequency comb generating device, the basic components of which include: a continuous laser, an electro-optic modulation device, a microwave source, a first interferometer, a first photodetector, a microcontroller, and a phase-shifting circuit. The electro-optic modulation device is connected to the output end of the continuous laser, the output end of the electro-optic frequency comb generating device, and the first interferometer; the first photodetector is connected to the first interferometer and the microcontroller; and the phase-shifting circuit is connected to the microwave source, the electro-optic modulation device, and the microcontroller.

[0007] In this electro-optic frequency comb generator, a continuous laser emits an optical signal to an electro-optic modulation device. The electro-optic modulation device modulates the optical signal emitted by the continuous laser based on the microwave signal (electrical signal) output from the microwave source via a phase-shifting circuit. The electro-optic modulation device then outputs a first portion of the modulated optical signal to the output terminal of the electro-optic frequency comb generator and outputs a second portion of the optical signal to a first interferometer. Typically, the microwave source outputs a microwave signal to the phase-shifting circuit, and this microwave signal is phase-shifted and output as an electrical signal to the electro-optic modulation device. The first interferometer generates two delayed optical signals from the second portion of the optical signal, with different delays. The first interferometer performs interference processing on these two delayed optical signals to generate a first interference optical signal. The first interference optical signal generated by the first interferometer is output to a first photodetector, which outputs the first detection result of the first interference optical signal to a microcontroller. The microcontroller adjusts the electrical signal output by the phase-shifting circuit based on the first detection result. In the above process, since the first detection result can characterize the phase information of the microwave signal output by the phase shifting circuit, the device can be used to realize the feedback adjustment of the phase of the microwave signal output by the phase shifting circuit based on the first detection result, thereby realizing the phase control and locking of the microwave signal loaded in the electro-optic modulation device, which is beneficial to generating an electro-optic comb with high flatness and wide spectral performance.

[0008] In one possible implementation, the first interferometer includes a Mach-Zehnder device, which has an output terminal and an input terminal. A first transmission path and a second transmission path are connected between the input terminal and the output terminal of the Mach-Zehnder device. The lengths of the two transmission paths and at least one of the materials of the two transmission paths are different. Specifically, when the second portion of the optical signal modulated by the electro-optic modulation device is output to the Mach-Zehnder device, the device splits this second portion into two optical signals. One optical signal enters the first transmission path for transmission, and the other optical signal enters the second transmission path for transmission. Since the lengths of the two transmission paths and at least one of the materials of the two transmission paths are different, two delayed optical signals can be formed after passing through the two transmission paths. The Mach-Zehnder device then performs interference processing on the two delayed optical signals to form a first interference optical signal.

[0009] In one possible implementation, the delay difference between the two delayed optical signals of the second part of the optical signal satisfies: θ c ω RF Δτ<λ, where θ c ω is the sum of the modulation depths of the phase modulator in the electro-optic modulation device. RFLet θ be the microwave modulation frequency of the microwave source, Δτ be the delay difference between the two delayed optical signals in the second part of the optical signal, and λ be the first minimum point of the zeroth-order Bessel function of the first kind. Specifically, θ c It can be represented as Where θ i The modulation depth of the i-th phase modulator can be represented as... V iRF V is the amplitude of the microwave signal applied to the i-th phase modulator. iπ Let be the half-wave voltage of the i-th phase modulator.

[0010] In one possible implementation, the electro-optic modulation device includes a first modulator and a second modulator, and the phase-shifting circuit includes a first phase shifter and a second phase shifter. The first modulator and the second modulator are cascaded sequentially between the output of the continuous laser and the output of the electro-optic frequency comb generator. The second modulator is also connected to a first interferometer. The first modulator is also connected to the first phase shifter, which is connected to a microcontroller and a microwave source. The second modulator is also connected to the second phase shifter, which is connected to the microcontroller and the microwave source. In this scheme, the optical signal output from the continuous laser can be modulated by two stages of modulators, and the phase of the microwave signal output to the two stages of modulators can be controlled by two phase shifters respectively, thereby achieving phase synchronization of the microwave signals loaded on the two modulators.

[0011] In one possible implementation, the electro-optic modulation device includes a first modulator and a second modulator, and the phase-shifting circuit includes a first phase shifter. The first and second modulators are cascaded sequentially between the output of the continuous laser and the output of the electro-optic frequency comb generator. The first modulator is also connected to a microwave source, and the second modulator is also connected to a first interferometer. The second modulator is also connected to the first phase shifter, which is connected to a microcontroller and the microwave source. In this scheme, the optical signal output from the continuous laser can be modulated by two stages of modulators, and the phase of the microwave signal output to the connected modulator can be controlled by a phase shifter, thereby achieving phase synchronization of the microwave signals loaded on the two modulators.

[0012] In one possible implementation, the electro-optic modulation device includes a first modulator, a second modulator, and a first coupler. Both the first and second modulators are phase modulators. The common terminal of the first coupler is connected to the second modulator, the first branch terminal of the first coupler is connected to a first interferometer, and the second branch terminal of the first coupler is connected to the output terminal of the electro-optic frequency comb generator. In this scheme, both modulators can be phase modulators.

[0013] In one possible implementation, the electro-optic modulation device includes a first modulator, a second modulator, a first coupler, and a bias circuit. The first modulator is a phase modulator, and the second modulator is an intensity modulator. The second modulator is also connected to the bias circuit, which is connected to the second modulator. The common terminal of the first coupler is connected to the second modulator, the first branch terminal of the first coupler is connected to a first interferometer, and the second branch terminal of the first coupler is connected to the output terminal of the electro-optic frequency comb generator. The electro-optic modulation device modulates the optical signal emitted by the continuous laser using a microwave source that outputs a microwave signal from a phase-shifting circuit. A first portion of the modulated optical signal is output to the output terminal of the electro-optic frequency comb generator, a second portion is output to the first interferometer, and a third portion is output to the bias circuit. This bias circuit outputs a bias voltage to the second modulator based on the input third portion of the optical signal to control the intensity modulator, causing it to operate at an orthogonal operating point.

[0014] In one possible implementation, the electro-optic modulation device includes a first modulator, a second modulator, a first coupler, and a bias circuit. The first modulator is a phase modulator, and the second modulator is an intensity modulator. The common terminal of the first coupler is connected to the second modulator, the first branch terminal of the first coupler is connected to a first interferometer, and the second branch terminal of the first coupler is connected to the bias circuit, which is connected to the second modulator. The electro-optic modulation device modulates the optical signal emitted by a continuous-wave laser using a microwave source that outputs a microwave signal from a phase-shifting circuit. A first portion of the modulated optical signal is output to the output of an electro-optic frequency comb generator, a second portion is output to the first interferometer, and a third portion is output to the bias circuit. This bias circuit outputs a bias voltage to the second modulator based on the input third portion of the optical signal to control the operating bias point of the intensity modulator, causing it to operate at an orthogonal operating point.

[0015] In one possible implementation, the electro-optic modulation device includes a first modulator, a second modulator, a first coupler, a second coupler, and a bias circuit. The first modulator is a phase modulator, and the second modulator is an intensity modulator. The common terminal of the first coupler is connected to the second modulator, a first branch terminal of the first coupler is connected to the common terminal of the second coupler, and a second branch terminal of the first coupler is connected to the output terminal of the electro-optic frequency comb generator. The first branch terminal of the second coupler is connected to a first interferometer, and the second branch terminal of the second coupler is connected to the bias circuit, which is connected to the second modulator. The electro-optic modulation device modulates the optical signal emitted by the continuous laser by using a microwave source to modulate the microwave signal output from the phase-shifting circuit. A first portion of the modulated optical signal is output to the output terminal of the electro-optic frequency comb generator, a second portion is output to the first interferometer, and a third portion is output to the bias circuit. The bias circuit outputs a bias voltage to the second modulator based on the input third portion of the optical signal. The third optical signal used for output bias voltage and the second optical signal used for feedback adjustment of the phase of the microwave signal output by the phase-shifting circuit both originate from the first coupler, thus avoiding lock-in errors caused by inconsistencies in the optical signals.

[0016] In one possible implementation, the electro-optic modulation device includes a first modulator, a second modulator, and a third modulator, and the phase-shifting circuit includes a first phase shifter and a second phase shifter. The first, second, and third modulators are cascaded sequentially between the output of the continuous laser and the output of the electro-optic frequency comb generator. The third modulator is also connected to a first interferometer. The second modulator is also connected to the first phase shifter, which is connected to a microcontroller and a microwave source. The first modulator is also connected to the microwave source. The third modulator is also connected to the second phase shifter, which is connected to the microcontroller and the microwave source. Of course, the more modulators cascaded, the wider the electro-optic frequency comb can be achieved. Furthermore, when using more than two modulators, phase shifters are required for all stages of the modulator except the first-stage modulator.

[0017] In one possible implementation, the electro-optic modulation device includes a first modulator, a second modulator, and a third modulator. The first and second modulators are phase modulators, and the third modulator is an intensity modulator. The electro-optic modulation device also includes a first coupler, a second coupler, a third coupler, and a bias circuit. The electro-optic frequency comb generator also includes a second interferometer and a second photodetector. The phase-shifting circuit includes a first phase shifter and a second phase shifter. The common terminal of the third coupler is connected to the second modulator, the first branch terminal of the third coupler is connected to the third modulator, the second branch terminal of the third coupler is connected to the second interferometer, the second interferometer is connected to the second photodetector, and the second photodetector is connected to a microcontroller. The electro-optic modulation device modulates the optical signal emitted by the continuous laser by using a microwave source to modulate the microwave signal output from the phase-shifting circuit. The second modulator outputs the modulated split signal to the second interferometer, and the third portion of the optical signal is output to the bias circuit. This bias circuit outputs a bias voltage to the third modulator based on the input third portion of the optical signal. The second interferometer generates two delayed optical signals from the split signal. These two delayed optical signals have different delays. The second interferometer performs interference processing on these two delayed optical signals with different delays to generate a second interference optical signal. The second interference optical signal generated by the second interferometer is output to the second photodetector. The second photodetector outputs the second detection result of the second interference optical signal to the microcontroller. The microcontroller adjusts the microwave signal output by the phase-shifting circuit based on the second detection result. In the above process, since the second detection result can characterize the phase information of the microwave signal output by the phase-shifting circuit, the device can use the second detection result to realize feedback adjustment of the phase of the microwave signal output by the phase-shifting circuit, thereby achieving phase control and locking of the microwave signal loaded in the electro-optic modulation device, which is beneficial for generating an electro-optic frequency comb with high flatness and wide spectral performance.

[0018] Secondly, embodiments of this application provide an electro-optic frequency comb generation method applicable to the electro-optic frequency comb generation apparatus of the first aspect described above. The method includes: modulating an optical signal output from a continuous laser using a microwave signal; outputting a first portion of the modulated optical signal; generating two delayed optical signals from a second portion of the modulated optical signal; interferencing the two delayed optical signals of the second portion of the optical signal to generate a first interference optical signal, wherein the two delayed optical signals of the second portion of the optical signal have different delays; and adjusting the microwave signal based on a first detection result of the first interference optical signal.

[0019] Based on one possible implementation of the second aspect, the time delay difference between the two optical signals in the second part of the optical signal during time delay interference processing satisfies: θ c ω RF Δτ<λ, where θ c ω is the sum of the modulation depths of the phase modulator in the electro-optic modulation device.RF Let θ be the microwave modulation frequency of the microwave source, Δτ be the delay difference between the two delayed optical signals in the second part of the optical signal, and λ be the first minimum point of the zeroth-order Bessel function of the first kind. Specifically, θ c It can be represented as Where θ i The modulation depth of the i-th phase modulator can be represented as... V iRF V is the amplitude of the microwave signal applied to the i-th phase modulator. iπ Let be the half-wave voltage of the i-th phase modulator.

[0020] Thirdly, embodiments of this application provide a light source, including an encapsulation structure, and any of the electro-optic frequency comb generating devices described in the first aspect encapsulated within the encapsulation structure.

[0021] Fourthly, embodiments of this application provide an electronic device whose structure includes a circuit board and a light source as described in the third aspect connected to the circuit board.

[0022] The technical problems solved and the technical effects achieved by the solutions provided in the second to fourth aspects can be referred to the description in the first aspect and its possible implementation methods, and will not be repeated here. Attached Figure Description

[0023] Figure 1 A schematic diagram of an electro-optic frequency comb generator provided for an embodiment of this application;

[0024] Figure 2 A schematic diagram of an electro-optic frequency comb generator provided for another embodiment of this application;

[0025] Figure 3 A schematic diagram of an electro-optic frequency comb generator provided for another embodiment of this application;

[0026] Figure 4 A Mach-Zehnder device structure diagram provided for embodiments of this application;

[0027] Figure 5 A Mach-Zehnder device structure diagram is provided for another embodiment of this application;

[0028] Figure 6 A schematic diagram of an electro-optic frequency comb generator provided for yet another embodiment of this application;

[0029] Figure 7 A schematic diagram of an electro-optic frequency comb generator provided for another embodiment of this application;

[0030] Figure 8 A schematic diagram of an electro-optic frequency comb generator provided for another embodiment of this application;

[0031] Figure 9 A schematic diagram of an electro-optic frequency comb generator provided for yet another embodiment of this application;

[0032] Figure 10 A corresponding embodiment provided for the present application Figure 9 Experimental results of the electro-optic frequency comb generator Figure 1 ;

[0033] Figure 11 A corresponding embodiment provided for the present application Figure 9 Simulation results of the electro-optic frequency comb generator Figure 1 ;

[0034] Figure 12 A corresponding embodiment provided for the present application Figure 9 Simulation results of the electro-optic frequency comb generator Figure 2 ;

[0035] Figure 13 A corresponding embodiment provided for the present application Figure 9 Simulation results of the electro-optic frequency comb generator Figure 3 ;

[0036] Figure 14 A corresponding embodiment provided for the present application Figure 9 Experimental results of the electro-optic frequency comb generator Figure 2 ;

[0037] Figure 15 A schematic diagram of an electro-optic frequency comb generator provided for another embodiment of this application;

[0038] Figure 16 A schematic diagram of an electro-optic frequency comb generator provided for another embodiment of this application;

[0039] Figure 17 A corresponding embodiment provided for the present application Figure 16 Experimental results of the electro-optic frequency comb generator Figure 1 ;

[0040] Figure 18 A corresponding embodiment provided for the present application Figure 16 Simulation results of the electro-optic frequency comb generator Figure 1 ;

[0041] Figure 19 A corresponding embodiment provided for the present application Figure 16 Simulation results of the electro-optic frequency comb generator Figure 2 ;

[0042] Figure 20A corresponding embodiment provided for the present application Figure 16 Simulation results of the electro-optic frequency comb generator Figure 3 ;

[0043] Figure 21 A corresponding embodiment provided for the present application Figure 16 Experimental results of the electro-optic frequency comb generator Figure 2 ;

[0044] Figure 22 A schematic diagram of an electro-optic frequency comb generator provided for another embodiment of this application;

[0045] Figure 23 A schematic diagram of an electro-optic frequency comb generator provided for another embodiment of this application;

[0046] Figure 24 A schematic diagram of an electro-optic frequency comb generator provided for yet another embodiment of this application;

[0047] Figure 25 A schematic diagram of an electro-optic frequency comb generator provided for another embodiment of this application;

[0048] Figure 26 A schematic diagram of an electro-optic frequency comb generator provided for another embodiment of this application;

[0049] Figure 27 A schematic diagram of an electro-optic frequency comb generator provided for yet another embodiment of this application;

[0050] Figure 28 A schematic diagram of an electro-optic frequency comb generator provided for another embodiment of this application. Detailed Implementation

[0051] The technical solutions of the embodiments of this application will be described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0052] In the following description, the terms "first," "second," etc., are used for descriptive convenience only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more. In the embodiments of this application, unless otherwise explicitly specified and limited, the term "connection" should be interpreted broadly; for example, "connection" can be a fixed connection, a detachable connection, or an integral part; it can be a direct connection or an indirect connection through an intermediate medium.

[0053] The typical technical terms used in the embodiments of this application are explained as follows:

[0054] Optical frequency comb (or simply optical frequency comb): It is a series of pulses with the same time intervals output by an ultrafast laser in the time domain, which are represented as a series of discrete spectral lines with the same frequency intervals in the frequency domain.

[0055] Electro-optic frequency comb: It is a type of optical frequency comb that modulates the continuous wave optical signal output by a continuous wave laser (continuous laser) into an optical frequency comb with equally spaced frequency comb teeth through the electro-optic effect.

[0056] Modulation depth: The modulation depth of a modulator is an important indicator of the degree of modulation when the modulator modulates the input signal. It describes the extent to which the modulated signal changes the parameters of the carrier signal (such as amplitude, frequency, phase, etc.). In the embodiments of this application, it mainly includes phase modulation of the carrier signal (i.e., the optical signal output by the continuous laser in the following embodiments) using a phase modulator (PM) and intensity modulation of the carrier signal using an intensity modulator (IM).

[0057] An optical frequency comb is a spectrum composed of a series of equally spaced frequency components with a coherent and stable phase relationship. It has significant applications in precision spectroscopy, optical communication, and other fields. An electro-optic frequency comb (or simply electro-optic comb) is an optical frequency comb generated using electro-optic modulation technology. Its core characteristics include flatness and spectral width, which directly determine its performance in applications such as spectral analysis, optical communication, and precision measurement. In optical communication, electro-optic combs can be used for multi-carrier generation, improving transmission capacity and spectral efficiency. In spectral analysis, electro-optic combs can serve as high-precision, wide-range light sources for high-resolution spectral analysis. In precision measurement, electro-optic combs can provide a highly stable frequency comb light source for optical clocks and frequency metrology. To broaden the spectral width and improve the flatness of the electro-optic comb, the electro-optic comb generator typically cascades multiple modulators at the output of a continuous laser (usually used to modulate the phase and intensity of the optical signal output by the continuous laser). These modulators are driven by the same microwave source. When the microwave signals loaded onto all modulators are in phase, the electro-optic comb generated by the optical signal output from the continuous laser after being modulated by each stage of modulators has the widest and flattest spectrum. However, the existence of uncertain optical phase delays in the cascaded multiple modulators, as well as the uncertain microwave phase delays of the microwave signals loaded onto all modulators, affects the output performance of the electro-optic comb.

[0058] A common practice is to use a phase shifter between the microwave source and the modulator to adjust the phase of the microwave signal applied to each modulator, thereby maintaining microwave signal synchronization. However, environmental disturbances in the microwave link can still cause inconsistencies in the phase of the microwave signal applied to each modulator, thus affecting the flatness and spectral performance of the electro-optic comb.

[0059] Reference Figure 1 As shown, an electro-optic frequency comb generator 10 includes: a continuous laser 11, a microwave source 12, a phase modulator 13, an intensity modulator 14, a bias circuit 15, a phase shifter 16, and an optical coupler 17. The input terminal of the phase modulator 13 is connected to the output terminal of the continuous laser 11. Here, the phase modulator 13 can be a single unit or N cascaded units. The phase control terminal of the phase modulator 13 is connected to the phase shifter 16, and the number of phase shifters 16 corresponds to the number of phase modulators 13. The phase shifter 16 is also connected to the microwave source 12. The output terminal of the phase modulator 13 is connected to the input terminal of the intensity modulator 14. The phase control terminal of the intensity modulator 14 is directly connected to the microwave source 12. The intensity modulator 14 is also connected to the bias circuit 15. The output terminal of the intensity modulator 14 is connected to the common terminal of the optical coupler 17. The optical coupler 17 also has two branch ports, one branch port is connected to a spectrometer, and the other branch port serves as the output terminal of the electro-optic frequency comb generator 10.

[0060] A continuous-wave laser 11 is used to emit an optical signal (which can be a continuous-wave optical signal); a microwave source 12 is used to load a microwave signal onto the modulator, modulating the phase or intensity of the optical signal passing through the modulator. The modulator includes a phase modulator 13 and an intensity modulator 14. The phase modulator 13 modulates the phase of the optical signal, and the intensity modulator 14 modulates the intensity of the optical signal. A bias circuit 15 provides real-time feedback control to adjust the bias voltage applied to the intensity modulator 14. The optical signal emitted by the continuous-wave laser 11, after passing through N phase modulators 13 and 1 intensity modulator 14, generates a modulated optical signal which is output to an optical coupler 17. The optical coupler 17 splits the optical signal into two paths: one path is used as an electro-optic frequency comb output, and the other path is used for detection by a spectrometer. The spectrum of the electro-optic frequency comb is observed using a spectrometer. Based on the observation results, the N phase shifters 16 loaded onto the N phase modulators 13 are manually adjusted. By adjusting the phase shift angle, the phase of the microwave signals of each cascaded modulator is aligned. When the microwave signals loaded onto the cascaded phase modulators 13 are in phase synchronization, the modulation effect of the cascaded modulators is coherent and constructive, the cumulative modulation depth reaches its maximum, and the output spectrum is the widest. When the cascaded phase modulators 13 and intensity modulators 14 are in phase synchronization, the square wave pulse output by the intensity modulator 14 is aligned with the frequency linear chirped region of the modulated optical field, achieving spectral power balance. At this time, the output spectral flatness is optimal. This method relies on the spectrometer to provide spectral information, which is expensive. Secondly, manually adjusting the phase shifters 16 based on the detected spectral results is subject to visual bias, making it difficult to guarantee the consistency of the electro-optic frequency comb. In addition, environmental disturbances cause phase changes in the microwave signal, requiring manual readjustment of the phase shifters 16, resulting in relatively low efficiency.

[0061] Reference Figure 2As shown, another electro-optic frequency comb generator 20 is provided, whose structure includes a continuous laser 21, a microwave source 22, an intensity modulator 23, a bias circuit 28, a phase modulator 24, a phase modulator 30, a first phase shifter 27, a second phase shifter 31, an optical filter 25, a photodetector 26, and a microcontroller 29. The input terminal of the intensity modulator 23 is connected to the output terminal of the continuous laser 21, the phase control terminal of the intensity modulator 23 is connected to the microwave source 22, the intensity modulator 23 is also connected to the bias circuit 28, and the output terminal of the intensity modulator 23 is connected to the input terminal of the phase modulator 24. The output terminal of the phase modulator 24 is connected to the input terminal of the phase modulator 30, the phase control terminal of the phase modulator 24 is connected to the first phase shifter 27, the phase control terminal of the phase modulator 30 is connected to the second phase shifter 31, the first phase shifter 27 is also connected to the microcontroller 29 and the microwave source 22, and the second phase shifter 31 is also connected to the microcontroller 29 and the microwave source 22. The output of phase modulator 30 is connected to the input of optical filter 25. Three photodetectors 26 are installed at the output of optical filter 25, and each photodetector 26 is connected to a microcontroller unit (MCU) 29. The optical signal emitted by continuous laser 21 is modulated by intensity modulator 23, phase modulator 24, and phase modulator 30. This modulated optical signal is then filtered by optical filter 25 to produce three electro-optic frequency combs. These three electro-optic frequency combs are converted into electrical signals by photoelectric conversion at photodetectors 26 and input to microcontroller 29. Microcontroller 29 then calculates the electrical signals converted from the three optical frequency combs and adjusts the microwave phase shift angles of the first phase shifter 27 and the second phase shifter 31, thereby achieving phase synchronization of the microwave signals emitted by the microwave source and loaded by intensity modulator 23, phase modulator 24, and phase modulator 30. Of the three electro-optic frequency combs, two are symmetrical about the carrier wave, while the third electro-optic frequency comb is far from the optical carrier wave and its power meets the detection requirements. The principle is as follows: when the power of the far-end electro-optical frequency comb is at its highest, it indicates that the cumulative modulation depth of the modulator has reached its maximum, and the phase of the microwave signal loaded by the modulator is aligned at this time. When the power of the two symmetrically positioned electro-optical frequency combs is equal, it indicates that the spectrum has reached a balanced state, and the phase of the microwave signal loaded by the cascaded modulator is aligned at this time. In addition, the optical filter 25 can usually be a wavelength-tunable optical filter (e.g., a wavelength selective switch, WSS) or a fixed-wavelength optical filter (e.g., a fiber bragg grating, FBG).When using a fixed-wavelength optical filter, this method uses the optical filter 25 to collect electro-optic frequency comb information as the basis for the microcontroller 29 to adjust the phase shift angles of the first phase shifter 27 and the second phase shifter 31. The optical filter 25 has wavelength selectivity and a certain filtering bandwidth, requiring the electro-optic frequency comb generator 20 to use a continuous laser of a specific wavelength, resulting in poor versatility. When using a wavelength-tunable optical filter, the system is bulky, the detection method is expensive, and the technology is limited by the minimum filtering bandwidth of the tunable optical filter. Furthermore, the filtering center frequency of the optical filter 25 is prone to shifting under long-term operation, making it impossible to accurately filter out the required electro-optic frequency comb, leading to adjustment failure of the microcontroller 29 and making it difficult to generate a stable, wide-spectrum, high-flatness electro-optic frequency comb.

[0062] Based on the above, this application provides an electro-optic frequency comb generating device and method, a light source, and electronic equipment, which can realize real-time phase alignment and locking of microwave signals, thereby generating a relatively stable electro-optic frequency comb with a wide spectrum and high flatness. The technical solution of this application will be described in detail below with reference to the accompanying drawings.

[0063] Reference Figure 3 As shown, an embodiment of this application provides an electro-optic frequency comb generator 30, the structure of which includes: a continuous laser 31, an electro-optic modulation device 32, a first interferometer 33, a first photodetector 34, a microcontroller 35, a phase-shifting circuit 36, and a microwave source 37. The output terminal of the continuous laser 31 is connected to the electro-optic modulation device 32, the electro-optic modulation device 32 is connected to the output terminal OUT of the electro-optic frequency comb generator 30 and the first interferometer 33, the first photodetector 34 is connected to the microcontroller 35 and the first interferometer 33, and the phase-shifting circuit 36 ​​is connected to the electro-optic modulation device 32, the microwave source 37, and the microcontroller 35.

[0064] Microwave source 37 outputs microwave signals (electrical signals) to electro-optic modulation device 32 through phase-shifting circuit 36. Electro-optic modulation device 32 modulates the optical signal input to continuous laser 31 based on the microwave signal output by microwave source 37. Electro-optic modulation device 32 outputs the first part of the modulated optical signal to the output terminal OUT of electro-optic frequency comb generator 30, and outputs the second part of the optical signal to first interferometer 33. First interferometer 33 performs interference processing on the second part of the optical signal into two delayed optical signals with different delays to generate a first interference optical signal. The first interference optical signal contains phase information used to extract and characterize the microwave signal output by phase-shifting circuit 36. The first interference optical signal is then output to first photodetector 34. This method avoids the use of expensive detection instruments and complex hardware structures to detect the electro-optic frequency comb. First photodetector 34 performs photoelectric conversion on the first interference optical signal to generate a photocurrent containing the first detection result. The photocurrent is then output to microcontroller 35. Microcontroller 35 detects the photocurrent and implements feedback control on phase-shifting circuit 36 ​​to adjust the microwave signal output by phase-shifting circuit 36. The electro-optic frequency comb generator 30 uses simple and inexpensive equipment for detection, and can achieve feedback control and real-time locking of microwave phase. This enables phase control and locking of the microwave signal loaded in the electro-optic modulation device 32, which is beneficial for generating electro-optic frequency combs with high flatness and wide spectral performance. This scheme has the advantages of high efficiency, accuracy, simple detection methods, and strong versatility.

[0065] In one example, refer to Figure 3 As shown, the time delay difference between the two delayed optical signals in the second part of the optical signal in the first interferometer 33 satisfies θ. c ω RF Δτ<λ, where θ c ω is the sum of the modulation depths of the phase modulator of the electro-optic modulation device 32. RF Let θ be the microwave modulation frequency of the microwave source, Δτ be the delay difference between the two delayed optical signals in the second part of the optical signal, and λ be the first minimum point of the zeroth-order Bessel function of the first kind. c It can be represented as Where θ i The modulation depth of the i-th phase modulator can be represented as... V iRF V is the amplitude of the microwave signal applied to the i-th phase modulator. iπ Let be the half-wave voltage of the i-th phase modulator.

[0066] In one example, refer to Figure 3 , Figure 4 and Figure 5 As shown, Figure 3 The first interferometer 33 in the middle can be Figure 4 or Figure 5The Mach-Zehnder device in the text can be an asymmetric Mach-Zehnder interferometer (AMZI). A Mach-Zehnder device typically includes an input and an output; a first transmission path and a second transmission path exist between the input and output of the Mach-Zehnder device; the lengths of the first and second transmission paths and the materials of the first and second transmission paths are different from each other. Specifically, refer to... Figure 4 and Figure 5 As shown, a specific structure of a Mach-Zehnder device is provided. This device includes an incident beamsplitter 331, two waveguide components L1 and L2 (waveguide component L1 is the first transmission path L1, and waveguide component L2 is the second transmission path L2), and an exit beamsplitter 332. The splitting ratio of both the incident beamsplitter 331 and the exit beamsplitter 332 is 50:50. The common terminal of the incident beamsplitter 331 serves as the input terminal of the Mach-Zehnder device. The two branch terminals of the incident beamsplitter 331 are connected to the two branch terminals of the exit beamsplitter 332 after passing through waveguide components L1 and L2, respectively. The common terminal of the exit beamsplitter 332 (serving as the output terminal of the Mach-Zehnder device) is connected to a first photodetector 34. The waveguide components consist of upper and lower waveguides, dividing the optical signal transmission path into two paths: the first transmission path L1 and the second transmission path L2. The time delay Δτ of the optical field passing through the upper and lower waveguides must satisfy the condition: θ c ω RF Δτ<3.8317, where ω RF For microwave modulation frequency, The summation of modulation depths of the cascaded phase modulators is given, and 3.8317 is an approximation of the first minimum point of the zero-order Bessel function of the first kind. The optical signal modulated by the modulator undergoes delayed interference after passing through a Mach-Zehnder device. This process can be used to extract the phase difference of the microwave signal loaded by the cascaded modulators. The input of the Mach-Zehnder device is connected to the electro-optic modulation device 32, and the output is connected to the first photodetector 34. The second part of the optical signal output from the electro-optic modulation device 32 is divided into two optical signals, which are transmitted in the first transmission path L1 and the second transmission path L2, respectively. Since the optical paths of the two parts of the optical signal are different in the first transmission path L1 and the second transmission path L2, the Mach-Zehnder device can perform interference processing on these two optical signals to generate the first interference optical signal. The first transmission path L1 and the second transmission path L2 of the Mach-Zehnder device can be different in length but the same in material, such as... Figure 4 As shown; or they can be of the same length but different materials, such as Figure 5 As shown, the first transmission path L1 and the second transmission path L2 can also have different lengths and materials.

[0067] In one example, such as Figure 6 As shown, the electro-optic modulation device 32 of the electro-optic frequency comb generator 30 includes a first modulator 321 and a second modulator 322, and the phase shifting circuit 36 ​​includes a first phase shifter 361 and a second phase shifter 362.

[0068] The first modulator 321 and the second modulator 322 are cascaded between the output of the continuous laser 31 and the output OUT of the electro-optic frequency comb generator 30. The second modulator 322 is also connected to the first interferometer 33. The first modulator 321 is also connected to the first phase shifter 361, and the second modulator 322 is also connected to the second phase shifter 362. The first phase shifter 361 is also connected to the microcontroller 35 and the microwave source 37. The second phase shifter 362 is connected to the microcontroller 35 and the microwave source 37.

[0069] In another approach, refer to Figure 7 As shown, the first modulator 321 may also omit the phase shifter. The electro-optic modulation device 32 includes the first modulator 321 and the second modulator 322, and the phase shifting circuit 36 ​​includes the first phase shifter 361. The first modulator 321 and the second modulator 322 are cascaded between the output terminal of the continuous laser 31 and the output terminal OUT of the electro-optic frequency comb generator 30. The first modulator 321 is also connected to the microwave source 37, and the second modulator 322 is also connected to the first interferometer 33. The second modulator 322 is also connected to the first phase shifter 361. The first phase shifter 361 is also connected to the microcontroller 35 and the microwave source 37.

[0070] For example, Figure 6 and Figure 7 The first modulator 321 and the second modulator 322 can be phase modulators, as detailed in the reference. Figure 8 As shown, the electro-optic modulation device 32 also includes a first coupler 323; the common terminal of the first coupler 323 is coupled to the second modulator 322, the first branch terminal of the first coupler 323 is coupled to the first interferometer 33, and the second branch terminal of the first coupler 323 is coupled to the output terminal OUT of the electro-optic frequency comb generator 30. The first coupler 323 can divide the modulated optical signal (modulated optical signal) output by the second modulator 322 into the aforementioned first part of the optical signal and the second part of the optical signal.

[0071] certainly, Figures 6-8 The electro-optic modulation device 32 of the electro-optic frequency comb generator 30 shown is illustrated using only two modulators as an example. Of course, in some examples, more modulators may be cascaded, for example, N modulators, where N is greater than or equal to 2. Additionally, see [reference needed]. Figure 6 As shown, each modulator is configured with a phase shifter, or refer to Figure 7The diagram shows the phase shifter configuration for modulators other than the first modulator.

[0072] In one example, refer to Figure 9 As shown, the electro-optic modulation device of the electro-optic frequency comb generator 30 has two phase modulators, which will be explained below.

[0073] The electro-optic modulation device 32 has a connection structure of two phase modulators: the input terminal of the first modulator 321 is connected to the output terminal of the continuous laser 31, and the output terminal of the first modulator 321 is connected to the input terminal of the second modulator 322. The common terminal of the first coupler 323 is connected to the output terminal of the second modulator 322, the first branch terminal of the first coupler 323 is connected to the Mach-Zehnder device 33, and the second branch terminal is connected to the output terminal OUT of the electro-optic frequency comb generator 30. See [reference needed] for details. Figure 9 As shown.

[0074] against Figure 9 The function of the device shown is described as follows:

[0075] Microwave source 37 outputs a cosine microwave signal with the required frequency and power. This signal is input to power divider 38 via its common terminal. Power divider 38 distributes the power of this microwave signal and outputs it at two branch ports. The first branch port of power divider 38 is connected to the phase control port of first modulator 321, and the second branch port of power divider 38 is connected to the phase control port of second modulator 322 via first phase shifter 361. The output terminal of microcontroller 35 is connected to the voltage control terminal of first phase shifter 361, and microcontroller 35 inputs a signal V = V0 to first phase shifter 361. bias +V d (t), where V bias The DC bias voltage is used to control the phase of the microwave signal introduced by the first phase shifter 361, V d (t)=V0sin(ω d t) is a low-frequency perturbation signal, which is used as a reference signal for the microcontroller 35 to perform phase-locking processing on the microwave signal.

[0076] Input light field E in The optical field output after passing through the first-stage phase modulator is expressed as follows: Where θ1 is the modulation depth of the phase modulator. The microwave phase introduced by the microwave signal loaded onto the phase modulator. When the single-frequency optical signal E output by the continuous laser 31... in Under the modulation of the microwave signal emitted by microwave source 37, the optical field after passing through two-stage phase modulators is E. out = Where, ω RFLet θ be the microwave modulation frequency, t be time, and θ1 and θ2 be the modulation depths introduced by the two phase modulators, respectively. The microwave phase introduced by the microwave signal loaded by the first modulator 321. The microwave phase introduced by the microwave signal loaded for the second modulator 322, when the phase difference between the microwave signals loaded by the two modulators... satisfy At this time, the microwave signals loaded on the first modulator 321 and the second modulator 322 are in a phase-synchronized state. At this time, the optical carrier can accumulate the maximum modulation depth, and the output electro-optical frequency comb width reaches its maximum. However, there are unavoidable delay differences in the actual system link, which makes it impossible for the system to directly achieve phase synchronization of the microwave signals of the cascaded modulators. Therefore, it is necessary to add a first phase shifter 361 to the microwave link to adjust the phase of the microwave signals of the cascaded modulators.

[0077] The second part of the optical signal, modulated by a two-stage phase modulator, is output to a Mach-Zehnder device 33. The Mach-Zehnder device 33 splits the second part of the optical signal into two delayed optical signals with different delays. The Mach-Zehnder device 33 then performs interference processing on these two delayed optical signals to generate a first interference optical signal. This first interference optical signal is output to a first photodetector 34. The first photodetector 34 can perform photoelectric conversion on the first interference optical signal and implement differential detection. The first photodetector 34 can be a balanced detector, etc. The first photodetector 34 has a low operating bandwidth and does not respond to microwave signals, but it can respond to low-frequency perturbation signals. The first photodetector 34 performs photoelectric conversion on the input first interference optical signal and outputs a photocurrent signal. Where J0(·) is the zeroth-order Bessel function of the first kind, θ c =θ1+θ2 is the sum of the modulation depths of the two cascaded phase modulators, and Δτ is the delay difference between the two delayed optical signals in the second part of the optical signal, Δτ satisfying θ c ω RF Δτ<λ, where λ is the first local minimum of the zeroth-order Bessel function of the first kind. Apply a perturbation signal V to the first phase shifter 361 d The perturbation phase introduced after (t). Photocurrent i PD The DC component i can be obtained through Taylor series expansion. PD (0) First harmonic component i PD (1) and second harmonic component i PD (2) , where the DC component i PD (0) exist There is a minimum value, and the first harmonic component i PD (1) It crosses zero. Therefore, i PD It can be used as a feedback signal for phase adjustment and locking of microwave signals in cascaded phase modulators.

[0078] Photocurrent i PD The output is sent to microcontroller 35, which samples and digitally quantizes the photocurrent signal using its internal analog-to-digital converter (ADC), and extracts Vo. bias The generated DC component i PD (0) and perturbation signal V d (t) generates the first harmonic component i PD (1) The microcontroller 35 analyzes signal characteristics through its internal logic unit and runs a PID control algorithm to dynamically adjust output parameters. Then, it generates an analog control signal through a digital-to-analog converter (DAC). The microcontroller 35 inputs the generated analog control signal to the first phase shifter 361 and controls the phase angle introduced by the first phase shifter 361, so that the phase of the microwave signal input from the microwave source 37 to the cascaded phase modulator is aligned and locked, thereby achieving synchronization.

[0079] Furthermore, embodiments of this application also provide an electro-optic frequency comb generation method, comprising the following steps:

[0080] 101. Modulate the optical signal output of a continuous laser using microwave signals.

[0081] 102. Output the first part of the modulated optical signal.

[0082] 103. Generate two delayed optical signals from the second part of the modulated optical signal. Perform interference processing on the two delayed optical signals of the second part of the optical signal to generate the first interference optical signal. The two delayed optical signals of the second part of the optical signal have different delays.

[0083] 104. Adjust the microwave signal based on the first detection result of the first interference optical signal.

[0084] Specifically, with Figure 9 Taking the hardware architecture of the electro-optic frequency comb generator 30 shown as an example, the electro-optic frequency comb generation method includes the following steps:

[0085] S1, Signal output of continuous laser and microwave source: The continuous laser 31 outputs a continuous wave light signal, and the microwave source 37 outputs a microwave signal.

[0086] S2, Transmission Spectrum Scan: Microcontroller 35 scan output bias voltage V bias And record the DC component i of the output signal of the first photodetector 34.PD (0) .

[0087] S3, Cascaded modulator microwave phase alignment: Set voltage V bias make i PD (0) It reaches the minimum value.

[0088] S4. Perturbation Signal Loading and Demodulation: The microcontroller 35 loads and demodulates the output voltage V. bias Based on the addition of a perturbation signal V d (t)=V0sin(ω d t), and the first harmonic component i is extracted using first harmonic demodulation technology. PD (1) .

[0089] S5, Cascaded modulator microwave phase lock: If the first harmonic component i PD (1) >0, towards i PD (1) Adjusting the direction of the decreasing value V bias If the first harmonic component i PD (1) <0, towards i PD (1) Adjusting the direction of numerical increase V bias Repeat the above process until i PD (1) By continuously approaching zero, phase locking of the microwave signal can be achieved.

[0090] The following are simulations and experiments to verify this scheme: Assuming the center wavelength of the continuous laser 31 is 1550.5nm, the microwave source 37 outputs a microwave frequency of 10GHz, the modulation depth introduced by the first modulator 321 and the second modulator 322 is 5π, and the delay difference Δτ of the Mach-Zehnder device 33 for the two delayed optical signals is 1ps, thus θ c ω RF Δτ = 1.97, satisfying θ c ω RF Δτ<λ, where λ≈3.8317. Figure 10 The bias voltage V on the first phase shifter 361 is shown. bias The microcontroller 35 calculates the DC component i of the photocurrent generated by the first photodetector 34 to establish a relationship with the photocurrent (the DC component is in arbitrary units au). PD (0) According to Figure 10 To adjust the bias voltage V applied to the first phase shifter 361 bias . Figure 11 The DC component of the photocurrent i is shown PD (0)Phase difference with microwave signal The relationship between them Figure 12 (1) to (4) are respectively Figure 11 The spectrum corresponding to the circled area shows that when the phase difference... The time spectrum is the widest, so the bias voltage V can be adjusted accordingly. bias make i PD (0) Minimize, so that Approaching 2nπ (n=0,1,2…), the phase of the microwave signal is aligned. Figure 13 This demonstrates how, after a perturbation signal is introduced into the first phase shifter 361, the first harmonic component i of the photocurrent output by the first photodetector 34 is shown. PD (1) and second harmonic component i PD (2) Regarding microwave phase difference The relationship between the photocurrent first harmonic component i PD (1) exist Since the time has passed zero, the bias voltage V can be adjusted accordingly. bias , making i PD (1) By continuously approaching zero, the phase of the microwave signal can be locked. Figure 14 This demonstrates how the cascaded phase modulator changes the bias voltage V applied by the first phase shifter 361. bias The microwave phase introduced by the first phase shifter 361 is controlled when the detected DC component i PD (0) At the lowest point Figure 10 At the circled area, the electro-optic comb spectrum reaches its widest point.

[0091] In some examples, such as Figure 15 As shown, the first modulator 321 is a phase modulator, the second modulator 322 is an intensity modulator, and the electro-optic modulation device 32 also includes a first coupler 323 and a bias circuit 324. The first modulator 321 and the second modulator 322 are cascaded between the output terminal of the continuous laser 31 and the output terminal OUT of the electro-optic frequency comb generator 30. The common terminal of the first coupler 323 is connected to the second modulator 322, the first branch terminal of the first coupler 323 is connected to the first interferometer 33, and the second branch terminal of the first coupler 323 is connected to the output terminal OUT of the electro-optic frequency comb generator 30. The second modulator 322 is also connected to the bias circuit 324. The electro-optic modulation device 32 is also configured to output a third portion of the modulated optical signal to the bias circuit 324; the bias circuit 324 is configured to output a bias voltage to the second modulator 322 based on the third portion of the optical signal.

[0092] Specific references Figure 16As shown, the electro-optic modulation device 32 has a two-modulator connection structure: a first modulator 321 and a second modulator 322 are cascaded sequentially between the output terminal of the continuous laser 31 and the output terminal OUT of the electro-optic frequency comb generator 30. The first modulator 321 is a phase modulator, and the second modulator 322 is an intensity modulator. The second modulator 322 is connected to a bias circuit 324 and also to the common terminal of a first coupler 323. The first branch of the first coupler 323 is connected to a Mach-Zehnder device 33, and the second branch of the first coupler 323 is connected to the output terminal OUT of the electro-optic frequency comb generator 30.

[0093] against Figure 16 The function of the device shown is described as follows:

[0094] Microwave source 37 outputs a cosine microwave signal with the required frequency and power. This signal is input to power divider 38 via its common terminal. Power divider 38 distributes the power of this microwave signal and outputs it at two branch ports. The first branch port of power divider 38 is connected to the phase control port of first modulator 321, and the second branch port of power divider 38 is connected to the phase control port of second modulator 322 via first phase shifter 361. The output terminal of microcontroller 35 is connected to the voltage control terminal of first phase shifter 361, and microcontroller 35 inputs a signal V = V0 to first phase shifter 361. bias +V d (t), where V bias The DC bias voltage is used to control the microwave phase introduced by the first phase shifter 361, V d (t)=V0sin(ω d t) is a low-frequency perturbation signal, used as a reference signal for microwave phase-locking processing by the microcontroller 35. The bias circuit 324 applies a bias voltage V to the second modulator 322. B =V π / 2, Microwave source 37 inputs microwave amplitude V to second modulator 322 RF =V π A microwave signal of / 2 is emitted, at which point the second modulator 322, i.e., the intensity modulator, can output a square wave signal with a duty cycle close to 50%, which can filter out the linear chirped region of the modulated optical field, thereby giving the output electro-optic frequency comb optimal flatness. Here, V... B and V RF The provided values ​​are merely examples, and adjustments can usually be made to a certain extent around the given example values. The specific values ​​provided here are merely examples and do not limit the scope of protection of this application.

[0095] Input light field E in The optical field form after modulation by the first-stage intensity modulator is: in, The microwave phase introduced by loading a microwave signal onto the intensity modulator. Combining this with the above expression for the light field modulated by the phase modulator, when the single-frequency optical signal E output by the continuous laser 31... in After undergoing one phase modulation and one intensity modulation, the output light field is Where θ1 is the modulation depth introduced by the first modulator 321, i.e., the phase modulator. The microwave phase introduced by the microwave signal loaded by the first modulator 321. The microwave phase introduced by the microwave signal loaded onto the second modulator 322. When the phase difference meets the condition... At this time, the first modulator 321 and the second modulator 322 are in a state of phase synchronization of microwave signals. However, there are unavoidable delay differences in the actual system link, which makes it impossible for the system to directly achieve phase synchronization of the microwave signals of the cascaded modulators. Therefore, it is necessary to add a first phase shifter 361 to the microwave link to adjust the phase of the microwave signals of the cascaded modulators.

[0096] The second part of the modulated optical signal, after being modulated by the phase modulator and intensity modulator, is output to the Mach-Zehnder device 33. The Mach-Zehnder device 33 splits the second part of the optical signal into two paths for interference processing to generate a first interference optical signal. The first interference optical signal is output to the first photodetector 34. The first photodetector 34 can perform photoelectric conversion on the first interference optical signal and realize differential detection. The first photodetector 34 can be a balanced detector, etc. The first photodetector 34 has a low operating bandwidth and does not respond to microwave signals, but it can respond to low-frequency perturbation signals. The first photodetector 34 performs photoelectric conversion on the input first interference optical signal and outputs a photocurrent signal i. PD ,have

[0097]

[0098] Where, ω c The frequency of the output optical signal of the continuous laser 31 The phase difference between the microwave signals applied to the phase modulator and the intensity modulator. Apply a perturbation signal V to the first phase shifter 361 d The perturbation phase introduced after (t) is θ1, which is the modulation depth of the first modulator 321, i.e., the phase modulator. Photocurrent i PD The DC component i can be obtained through Taylor series expansion. PD (0) First harmonic component i PD (1) and second harmonic component i PD (2) , where the DC component i PD (0) exist The time is the median, and the second harmonic component i PD (2) It crosses zero. Therefore, i PD It can be used as a feedback signal for phase adjustment and locking of the microwave signal in the cascaded modulator. The microcontroller 35 calculates and processes the photocurrent input to the first photodetector 34, and controls the phase shift angle of the first phase shifter 361 according to the calculation result, so as to realize the phase synchronization state of the microwave signals of the phase modulator and the intensity modulator.

[0099] Photocurrent i PD The output is sent to microcontroller 35, which samples and digitally quantizes the photocurrent signal using its internal analog-to-digital converter (ADC), and extracts Vo. bias The generated DC component i PD (0) and perturbation signal V d (t) generates the second harmonic component i PD (2) The microcontroller 35 analyzes signal characteristics through its internal logic unit and runs a PID control algorithm to dynamically adjust output parameters. It then generates an analog control signal via a digital-to-analog converter (DAC). The microcontroller 35 inputs this analog control signal to the first phase shifter 361, controlling the phase angle introduced by the first phase shifter 361. This ensures phase alignment and locking of the microwave signal input from the microwave source 37 to the cascaded modulator, achieving synchronization. Furthermore, in this type of electro-optic frequency comb generator 30, the intensity modulator and phase modulator are interchangeable.

[0100] Specifically, with Figure 16 Taking the hardware architecture of the electro-optic frequency comb generator 30 shown as an example, the electro-optic frequency comb generation method includes the following steps:

[0101] S1. Continuous laser and microwave source signal output: The continuous laser 31 outputs a continuous wave light signal, the microwave source 37 outputs a microwave signal, and the bias circuit 324 applies a bias voltage V through the bias control point of the second modulator 322, i.e., the intensity modulator. B =V π / 2, Microwave source 37 inputs an amplitude of V to second modulator 322. RF =V π A microwave signal of / 2, where V here B and V RF The provided values ​​are merely examples, and adjustments can usually be made to a certain extent around the given example values. The specific values ​​provided here are merely examples and do not limit the scope of protection of this application.

[0102] S2, Intensity modulator bias voltage control: Scan intensity modulator bias voltage VB This allows it to operate at orthogonal operating points.

[0103] S3, Transmission Spectrum Scan: Microcontroller 35 scan output bias voltage V bias And record the DC component i of the output signal of the first photodetector 34. PD (0) .

[0104] S4, Cascaded modulator microwave phase alignment: Set voltage V bias , so that i PD (0) Median point.

[0105] S5. Perturbation Signal Loading and Demodulation: The microcontroller 35 loads and demodulates the output voltage V. bias Based on the addition of a perturbation signal V d (t)=V0sin(ω d t), and second harmonic component i is extracted using second harmonic demodulation technology. PD (2) .

[0106] S6, Cascaded modulator microwave phase lock: If the second harmonic component i PD (2) >0, towards i PD (2) Adjusting the direction of the decreasing value V bias If the second harmonic component i PD (2) <0, towards i PD (2) Adjusting the direction of numerical increase V bias Repeat the above process until i PD (2) By continuously approaching zero, microwave phase locking can be achieved.

[0107] The following are simulations and experiments verifying this scheme. Assume the center wavelength of the continuous-wave laser 31 is 1550.5 nm, the microwave source 37 outputs a microwave frequency of 10 GHz, the modulation depth introduced by the phase modulator is 5π, and the bias voltage V of the intensity modulator... B =V π / 2. Microwave port input microwave amplitude V RF =V π / 2, Mach-Zehnder device 33 delay difference Δτ=1ps. Figure 17 Showing the bias voltage V on the first phase shifter 361 bias The microcontroller 35 calculates the DC component i of the photocurrent to establish a relationship between the photocurrent generated by the first photodetector 34 and the photocurrent itself. PD (0) According to Figure 17To adjust the bias voltage V applied to the first phase shifter 361 bias . Figure 18 It shows different microwave phase differences DC component of time current i PD (0) , Figure 19 (1) to (6) are respectively Figure 18 The spectrum corresponding to the circled dot is in the current At that time, the DC component i PD (0) This is the median value, from which the bias voltage V can be adjusted. bias make i PD (0) Minimize, so that Approaching nπ (n=0, 1, 2…), the microwave phase is aligned at this point. Figure 20 This demonstrates the first harmonic component i of the photocurrent output by the first photodetector 34 after the addition of a low-frequency perturbation signal to the first phase shifter 361. PD (1) and second harmonic component i PD (2) Regarding microwave phase difference The relationship can be seen from the second harmonic component i. PD (2) exist When the time passes zero, the bias voltage V applied to the first phase shifter 361 can be adjusted accordingly. bias , making i PD (2) By continuously approaching zero, the phase of the microwave signal can be locked. Figure 21 This demonstrates the DC component of the photocurrent, i. PD (0) When located at the median point Figure 17 The electro-optic frequency comb spectrum output at the circled area has the best spectral flatness.

[0108] In some examples, refer to Figure 22 As shown, the first modulator 321 is a phase modulator and the second modulator 322 is an intensity modulator; the electro-optic modulation device 32 also includes a first coupler 323 and a bias circuit 324; the common terminal of the first coupler 323 is connected to the second modulator 322, the first branch terminal of the first coupler 323 is coupled to the first interferometer 33, and the second branch terminal of the first coupler 323 is connected to the bias circuit 324; the bias circuit 324 is also connected to the second modulator 322; the second modulator 322 is also connected to the output terminal OUT of the electro-optic frequency comb generator 30; the electro-optic modulation device 32 is also configured to output a third part of the modulated optical signal to the bias circuit 324; the bias circuit 324 is configured to output a bias voltage to the second modulator 322 based on the third part of the optical signal.

[0109] Specific references Figure 23 As shown, the intensity modulator is a device with two output ports. The electro-optic modulation device 32 has a connection structure of two modulators: the first modulator 321 and the second modulator 322 are cascaded between the output terminal of the continuous laser 31 and the output terminal OUT of the electro-optic frequency comb generator 30, wherein the first modulator 321 is a phase modulator and the second modulator 322 is an intensity modulator. The common terminal of the first coupler 323 is connected to the second modulator 322, the first branch terminal of the first coupler 323 is connected to the Mach-Zehnder device 33, and the second branch terminal of the first coupler 323 is connected to the bias circuit 324; the second modulator 322 is connected to the output terminal OUT of the electro-optic frequency comb generator 30.

[0110] against Figure 23 The function of the device shown is described as follows:

[0111] Microwave source 37 outputs a cosine microwave signal with the required frequency and power. This signal is input to power divider 38 via its common terminal. Power divider 38 distributes the power of the microwave signal and outputs it at two branch ports. The first branch port of power divider 38 is connected to the phase control port of first modulator 321, and the second branch port of power divider 38 is connected to the phase control port of second modulator 322 via first phase shifter 361. The output of microcontroller 35 is connected to the voltage control terminal of first phase shifter 361. The phase-locked mode of the microwave signal in this device is the same as... Figure 16 The electro-optic frequency comb generator 30 is identical. The single-frequency optical signal E output by the continuous laser 31... in After undergoing one phase modulation and one intensity modulation sequentially, the second modulator 322 is connected to the first coupler 323, and also to the output terminal OUT of the electro-optic frequency comb generator 30. The first portion of the optical signal is output to the output terminal OUT of the electro-optic frequency comb generator 30, the second portion is output to the first interferometer 33, and the third portion is output to the bias circuit 324. Figure 16 Compared to the device, Figure 16 In the device shown, the first portion of the optical signal output from the continuous laser 31 is output from the second modulator 322 to the second branch of the first coupler 323 as the output of the electro-optic frequency comb generator 30. Figure 23 In the optical signal output from the continuous laser 31 shown, the first part of the optical signal is directly output from the second modulator 322 to the output terminal OUT of the electro-optic frequency comb generator 30. This connection method, where the electro-optic frequency comb is directly output from the intensity modulator, can improve the output power of the electro-optic frequency comb. However, the phase alignment and locking method of the microwave signal in this connection method is the same as... Figure 16 The electro-optic frequency comb generator 30 is the same.

[0112] In one example, refer to Figure 24 As shown, the electro-optic modulation device 32 includes a first modulator 321, a second modulator 322, and a third modulator 326, wherein the first modulator 321 and the second modulator 322 are phase modulators, and the third modulator 326 is an intensity modulator. The electro-optic modulation device 32 also includes a first coupler 323, a second coupler 325, and a bias circuit 324. The phase-shifting circuit 36 ​​includes a first phase shifter 361 and a second phase shifter 362. The common terminal of the first coupler 323 is connected to the third modulator 326, the first branch terminal of the first coupler 323 is connected to the first interferometer 33, and the second branch terminal of the first coupler 323 is connected to the output terminal OUT of the electro-optic frequency comb generator 30. The third modulator 326 is also connected to the bias circuit 324. The common terminal of the second coupler 325 is connected to the second modulator 322, the first branch terminal of the second coupler 325 is connected to the third modulator 326, the second branch terminal of the second coupler 325 is connected to the second interferometer 330; the second interferometer 330 is connected to the second photodetector 341; the second photodetector 341 is connected to the microcontroller 35.

[0113] Microwave source 37 outputs a cosine microwave signal with the required frequency and power, which is input to power divider 38 via its common terminal. Power divider 38 distributes the power of the microwave signal and outputs it through three branch ports. The first branch port of power divider 38 is connected to the phase control port of first modulator 321. The second branch port of power divider 38 is connected to the phase control port of second modulator 322 via first phase shifter 361. The third branch port of power divider 38 is connected to the phase control port of third modulator 326 via second phase shifter 362. The first output terminal of microcontroller 35 is connected to the voltage control terminal of first phase shifter 361, and the second output terminal of microcontroller 35 is connected to the voltage control terminal of second phase shifter 362.

[0114] The single-frequency optical signal E output by the continuous laser 31 in After undergoing two phase modulations and one intensity modulation, the microcontroller 35 inputs a signal V1 = V to the first phase shifter 361. 1nias +V 1d (t), where V 1d (t)=V 10 sin(ω 1d t), input signal V2 = V to the second phase shifter 362. 2bias +V 2d (t), where V 2d (t)=V 20 sin(ω 2d (t). The function of the first phase shifter 361 is to adjust the phase difference of the microwave signal between the first modulator 321 and the second modulator 322. Make it satisfy The phase synchronization condition; the function of the second phase shifter 362 is to adjust the phase difference between the microwave phase generated by the cascaded first modulator 321 and second modulator 322 and the microwave signal of the third modulator 326. Make it satisfy The phase synchronization condition. The bias circuit 324 applies a bias voltage V to the third modulator 326. B =V π / 2, Microwave source 37 inputs microwave amplitude V to third modulator 326 RF =V π / 2 microwave signal, bias circuit 324 scans bias voltage V B This allows it to operate at orthogonal operating points.

[0115] The optical signal output from the continuous laser 31, after being modulated by the first modulator 321 and the second modulator 322, is split and enters the second interferometer 330. The second interferometer 330 generates two delayed optical signals with different time delays from the split signal and performs interference processing to generate a second interference optical signal, which enters the second photodetector 341. Another portion of the optical signal output from the continuous laser 31, after being modulated by the first modulator 321 and the second modulator 322, is modulated by the third modulator 326. The first portion of the optical signal modulated by the third modulator 326 is output to the output terminal OUT of the electro-optic frequency comb generator 30, and the second portion is output to the first interferometer 33. The first interferometer 33 generates two delayed optical signals with different time delays from the second portion of the optical signal and performs interference processing to generate a first interference optical signal, which is input to the first photodetector 34. The time delay difference between the first interferometer 33 and the second interferometer 330 both satisfy: θ c ω RF Δτ<λ, where θ c λ is the sum of the modulation depths of the cascaded phase modulators of the electro-optic modulation device 32, and λ is the first minimum point of the zero-order Bessel function of the first kind.

[0116] The first interference light signal is output to the first photodetector 34, and the second interference light signal is output to the second photodetector 341. Both the first and second photodetectors 34 and 341 have low operating bandwidths and do not respond to microwave signals, but can respond to low-frequency perturbation signals. The second photodetector 341 performs photoelectric conversion to generate... It can be expanded into a DC component using Taylor series. First harmonic component and second harmonic components The first photodetector 34 performs photoelectric conversion to generate photocurrent. It can be expanded into a DC component using Taylor series. First harmonic component and second harmonic components

[0117] Photocurrent and The signal is input to microcontroller 35, which samples and digitally quantizes the photocurrent signal using its internal analog-to-digital converter (ADC) and extracts V. 1bias The generated DC component and perturbation signal V 1d (t) generates the first harmonic component Extract V 2bias The generated DC component and perturbation signal V 2d (t) generates the second harmonic component The microcontroller 35 analyzes signal characteristics through its internal logic unit and runs a PID control algorithm to dynamically adjust output parameters. Then, it generates an analog control signal through a digital-to-analog converter (DAC). The microcontroller 35 inputs the generated analog control signal to the first phase shifter 361 and the second phase shifter 362, respectively controlling the phase angle introduced by the first phase shifter 361 and the second phase shifter 362, so that the phase of the microwave signal input from the microwave source 37 to the cascaded modulator is aligned and locked, thereby achieving synchronization.

[0118] Specifically, with Figure 24 Taking the hardware architecture of the electro-optic frequency comb generator 30 shown as an example, the electro-optic frequency comb generation method includes the following steps:

[0119] S1. Continuous laser and microwave source signal output: The continuous laser 31 outputs a continuous wave light signal, the microwave source 37 outputs a microwave signal, and the bias circuit 324 applies a bias voltage V to the third modulator 326. B =V π / 2, Microwave source 37 inputs an amplitude of V to third modulator 326. RF =V π A microwave signal of / 2, where V here B and V RF The provided values ​​are merely examples, and adjustments can usually be made to a certain extent around the given example values. The specific values ​​provided here are merely examples and do not limit the scope of protection of this application.

[0120] S2, Intensity modulator bias voltage control: Scan the bias voltage of the third modulator 326 to make it operate at the quadrature operating point.

[0121] S3, Transmission Spectrum Scanning and Phase Alignment: Microcontroller 35 scans the bias voltage V at the first output port. 1bias And record the DC component of the output signal of the second photodetector 341. Set voltage V 1bias make Located at the minimum point. Microcontroller 35 scans the bias voltage V at the second output port. 2bias And record the DC component of the output signal of the first photodetector 34. Set voltage V 2bias make Located at the median point.

[0122] S4. Perturbation Signal Loading and Demodulation: The microcontroller 35 loads and demodulates the output voltage V. 1bias Based on the addition of a perturbation signal V 1d (t)=V 10 sin(ω 1d t), and the first harmonic component i is extracted using the first harmonic phase-locked loop technique. PD1 (1) The microcontroller 35 outputs voltage V 2bias Based on the addition of a perturbation signal V 2d (t)=V 20 sin(ω 2d t), and second harmonic components are extracted using second harmonic demodulation technology.

[0123] S5, Cascaded modulator microwave phase lock: If the first harmonic component Towards Adjusting the direction of the decreasing value V 1bias If the first harmonic component Towards Adjusting the direction of numerical increase V 1bias Repeat the above process to make It continuously approaches zero. If the second harmonic component... Towards Adjusting the direction of the decreasing value V 2bias If the second harmonic component Towards Adjusting the direction of numerical increase V 2bias Repeat the above process to make It keeps getting closer to zero.

[0124] certainly, Figure 24 The electro-optic modulation device 32 of the electro-optic frequency comb generator 30 shown is illustrated using only two phase modulators and one intensity modulator as an example. Of course, in some examples, more modulators may be cascaded, for example, N modulators, where N is greater than or equal to 2, including N-1 phase modulators and one intensity modulator. Additionally, see [reference needed]. Figure 6 As shown, each modulator is configured with a phase shifter, or refer to Figure 7 The diagram shows the phase shifter configuration for modulators other than the first modulator.

[0125] Specific references Figure 25 As shown, the electro-optic modulation device 32 includes N modulators, of which N-1 are phase modulators and one is an intensity modulator. The phase-shifting circuit 36 ​​includes N-1 phase shifters. The electro-optic modulation device 32 also includes a bias circuit 324 and N-1 couplers. The electro-optic frequency comb generator 30 also includes a continuous laser 31, N-1 interferometers, N-1 photodetectors, a microcontroller 36, and a microwave source 37. The N modulators are cascaded sequentially between the continuous laser 31 and the output terminal OUT of the electro-optic frequency comb generator 30. The first modulator is also connected to the microwave source, the second modulator is also connected to phase shifter 1, the third modulator is also connected to phase shifter 2, and so on, with the Nth modulator connected to phase shifter N-1. Couplers are configured starting from the second modulator. Each coupler splits the optical signal into two parts. One part of the optical signal is output to the next-stage modulator for modulation, and so on, until the modulated optical signal after the Nth modulator is output to the output terminal OUT of the electro-optic frequency comb generator 30 via coupler N-1. The second part of the optical signal is output to the interferometer N-1, and the third part is output to the bias circuit 324. The split signal is output to the interferometer corresponding to the coupler. Each interferometer generates two delayed optical signals with different delays from the input optical signal and generates interferometric optical signals. Each interferometric optical signal is processed by the corresponding photodetector to generate photocurrents. Each photocurrent is output to the microcontroller 35. The microcontroller 35 processes each photocurrent signal to generate corresponding analog control signals. Then, the microcontroller 35 sends each analog control signal to the corresponding phase shifter through the corresponding output port to adjust the phase shift angle of each phase shifter, so that the phase of the microwave signal loaded on each modulator is synchronized. For specific adjustment of phase alignment and locking methods, please refer to [reference needed]. Figure 24 The method of the device shown will not be described in detail here.

[0126] Of course, in some examples, it is also possible to set up only one interferometer and one photodetector for all phase modulators (the first N-1 stage modulators), i.e. Figure 25 In this example, only coupler N-2, interferometer N-2, and photodetector N-2 are retained for all phase modulators; couplers 1 to (N-3), interferometers 1 to (N-3), and photodetectors 1 to (N-3) are no longer provided. Of course, in some examples, several sets of couplers, interferometers, and photodetectors can be selectively provided for all phase modulators, for example, a set of couplers, interferometers, and photodetectors can be provided at equal intervals between the same number of phase modulators.

[0127] Additionally, for cases where all modulators are equipped with phase shifters, a coupler needs to be installed after each modulator stage, with the split signal from each coupler outputting to the corresponding interferometer. The adjustment phase alignment and locking methods for this device can be found in [reference needed]. Figure 24The adjustment method of the device shown will not be described in detail here.

[0128] In one example, refer to Figure 26 As shown, the electro-optic modulation device 32 includes a first modulator 321, a second modulator 322, and a third modulator 326, wherein the first modulator 321 and the second modulator 322 are phase modulators, and the third modulator 326 is an intensity modulator. The electro-optic modulation device 32 also includes a first coupler 323, a second coupler 325, and a bias circuit 324. The phase-shifting circuit 36 ​​includes a first phase shifter 361 and a second phase shifter 362. The common terminal of the first coupler 323 is connected to the third modulator 326, the first branch terminal of the first coupler 323 is connected to the first interferometer 33, and the second branch terminal of the first coupler 323 is connected to the bias circuit 324. The common terminal of the second coupler 325 is connected to the second modulator 322, the first branch terminal of the second coupler 325 is connected to the third modulator 326, and the second branch terminal of the second coupler 325 is connected to the second interferometer 330; the second interferometer 330 is connected to the second photodetector 341; the second photodetector 341 is connected to the microcontroller 35. (Comparison) Figure 24 The device shown, Figure 24 In the device shown, the first portion of the optical signal output from the continuous laser 31 is derived from the output of the third modulator 326 to the second branch of the first coupler 323, serving as the output of the electro-optic frequency comb generator 30. Figure 26 In the illustrated device, the first portion of the optical signal output from the continuous laser 31 is directly output from the third modulator 326 to the output terminal OUT of the electro-optic frequency comb generator 30. This connection method, where the electro-optic frequency comb is directly output from the intensity modulator, can increase the output power of the electro-optic frequency comb. The microwave phase alignment and locking methods of this connection method are the same as... Figure 24 The electro-optic frequency comb generator 30 shown is the same.

[0129] Furthermore, the aforementioned scheme is mainly illustrated using an intensity modulator with two output terminals. In some examples, the intensity modulator may also have only one output terminal. Again, taking the electro-optic frequency comb generator 30's electro-optic modulation device, which includes two modulators, as an example, refer to... Figure 27As shown, the first modulator 321 is a phase modulator and the second modulator 322 is an intensity modulator; the electro-optic modulation device 32 also includes a first coupler 323, a second coupler 325, and a bias circuit 324; the common terminal of the first coupler 323 is connected to the second modulator 322, the first branch terminal of the first coupler 323 is connected to the common terminal of the second coupler 325, and the second branch terminal of the first coupler 323 is connected to the output terminal OUT of the electro-optic frequency comb generator 30; the first branch terminal of the second coupler 325 is connected to the first interferometer 33, and the second branch terminal of the second coupler 325 is connected to the bias circuit 324; the bias circuit 324 is also connected to the second modulator 322; the electro-optic modulation device 32 is also configured to output a third part of the modulated optical signal to the bias circuit 324; the bias circuit 324 is configured to output a bias voltage to the second modulator 322 based on the third part of the optical signal. Compared to the electro-optic frequency comb generator 30 using an intensity modulator with two output ports, the electro-optic frequency comb generator using a single-port output intensity modulator has its third portion of the optical signal used for outputting the bias voltage and the second portion of the optical signal used for feedback adjustment of the phase of the microwave signal output by the phase-shifting circuit both originating from the first coupler 323, thus avoiding locking errors introduced by optical signal inconsistency. Furthermore, in this type of electro-optic frequency comb generator 30, the intensity modulator and phase modulator are interchangeable.

[0130] Furthermore, still taking the example of an intensity modulator having only one output terminal, and the electro-optic modulation device 32 of the electro-optic frequency comb generator 30 including two phase modulators and one intensity modulator, refer to... Figure 28The electro-optic modulation device 32 shown includes: a first modulator 321, a second modulator 322, and a third modulator 326; the first modulator 321 and the second modulator 322 are phase modulators, and the third modulator 326 is an intensity modulator; the phase shifting circuit 36 ​​includes a first phase shifter 361 and a second phase shifter 362; the first modulator 321, the second modulator 322, and the third modulator 326 are cascaded sequentially between the output terminal of the continuous laser 31 and the output terminal OUT of the electro-optic frequency comb generator 30; the first modulator 321 is connected to the microwave source 37; the second modulator 322 is also connected to the first phase shifter 361; the third modulator 326 is also connected to the second phase shifter 362; the first phase shifter 361 is also connected to the microcontroller 35 and the microwave source 37; the second phase shifter 362 is also connected to the microcontroller 35 and the microwave source 37. The electro-optic frequency comb generator 30 further includes a second interferometer 330 and a second photodetector 341; the electro-optic modulation device 32 further includes a third coupler 327, wherein the common end of the third coupler 327 is connected to the second modulator 322, the first branch end of the third coupler 327 is connected to the third modulator 326, and the second branch end of the third coupler 327 is connected to the second interferometer 330; the second photodetector 341 is connected to the second interferometer 330 and the microcontroller 35; the electro-optic modulation device 32 is configured to output the split signal in the optical signal modulated by the second modulator 322 to the second interferometer 330; the second interferometer 330 is configured to perform interference processing on the two delayed optical signals generated by the split signal to generate a second interference optical signal, wherein the two delayed optical signals of the split signal have different delays; the microcontroller 35 is configured to adjust the microwave signal output by the first phase shifter 361 based on the second detection result of the second photodetector 341 on the second interference optical signal. Compared to the electro-optic frequency comb generator 30 which uses an intensity modulator with two output ports, the third portion of the optical signal used to output the bias voltage and the second portion of the optical signal used for feedback adjustment of the phase of the microwave signal output by the phase-shifting circuit in the electro-optic frequency comb generator which uses an intensity modulator with a single port output both come from the first coupler 323, thus avoiding locking errors caused by inconsistencies in the optical signals.

[0131] This application also provides a light source, including an encapsulation structure and an electro-optic comb generator 30 as described above.

[0132] This application also provides an electronic device, including a circuit board and an electro-optic frequency comb generator 30 as described above connected to the circuit board.

[0133] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. An electro-optic frequency comb generator, characterized in that, include: Continuous laser, electro-optic modulation device, microwave source, first interferometer, first photodetector, microcontroller and phase shifting circuit; The electro-optic modulation device is connected to the output end of the continuous laser, the output end of the electro-optic frequency comb generator, and the first interferometer; the first photodetector is connected to the first interferometer and the microcontroller; and the phase-shifting circuit is connected to the microwave source, the electro-optic modulation device, and the microcontroller. The electro-optic modulation device is configured to modulate the optical signal output by the continuous laser based on the microwave signal output by the microwave source through the phase-shifting circuit; The electro-optic modulation device is configured to output a first portion of the modulated optical signal to the output terminal of the electro-optic frequency comb generator, and output a second portion of the optical signal to the first interferometer. The first interferometer is configured to perform interference processing on the two delayed optical signals generated from the second part of the optical signal to generate a first interference optical signal, wherein the two delayed optical signals of the second part of the optical signal have different delays; The microcontroller is configured to adjust the microwave signal output by the phase shifter circuit based on the first detection result of the first photodetector on the first interference light signal.

2. The electro-optic frequency comb generator according to claim 1, characterized in that, The first interferometer includes a Mach-Zehnder device, which includes an input terminal and an output terminal; The input terminal of the Mach-Zehnder device and the output terminal of the Mach-Zehnder device include a first transmission path and a second transmission path; The lengths of the first transmission path and the second transmission path, and the materials of the first transmission path and the second transmission path, are different from at least one.

3. The electro-optic frequency comb generating device according to claim 1 or 2, characterized in that, The delay difference between the two delayed optical signals in the second part of the optical signal satisfies: θ c ω RF Δτ<λ, where θ c ω is the sum of the modulation depths of the phase modulator of the electro-optic modulation device. RF θ is the microwave modulation frequency of the microwave source, Δτ is the delay difference between the two delayed optical signals of the second part of the optical signal, and λ is the first minimum point of the zero-order Bessel function of the first kind; specifically θ c It can be represented as Where θ i The modulation depth of the i-th phase modulator can be represented as... V iRF V is the amplitude of the microwave signal applied to the i-th phase modulator. iπ Let be the half-wave voltage of the i-th phase modulator.

4. The electro-optic frequency comb generating device according to any one of claims 1-3, characterized in that, The electro-optic modulation device includes: a first modulator and a second modulator; the phase shifting circuit includes a first phase shifter and a second phase shifter; The first modulator and the second modulator are cascaded sequentially between the output of the continuous laser and the output of the electro-optic frequency comb generator, and the second modulator is also connected to the first interferometer; The first modulator is also connected to the first phase shifter, and the second modulator is also connected to the second phase shifter; The first phase shifter is also connected to the microcontroller and the microwave source; The second phase shifter is connected to the microcontroller and the microwave source.

5. The electro-optic frequency comb generating device according to any one of claims 1-3, characterized in that, The electro-optic modulation device includes: a first modulator and a second modulator; the phase shifting circuit includes a first phase shifter; The first modulator and the second modulator are cascaded sequentially between the output of the continuous laser and the output of the electro-optic frequency comb generator. The second modulator is also connected to the first interferometer. The first modulator is also connected to the microwave source. The second modulator is also connected to the first phase shifter; The first phase shifter is also connected to the microcontroller and the microwave source.

6. The electro-optic frequency comb generating device according to claim 4 or 5, characterized in that, The first modulator and the second modulator are phase modulators; The electro-optic modulation device further includes a first coupler; The common terminal of the first coupler is coupled to the second modulator, the first branch terminal of the first coupler is coupled to the first interferometer, and the second branch terminal of the first coupler is coupled to the output terminal of the electro-optic frequency comb generator.

7. The electro-optic frequency comb generating device according to claim 4 or 5, characterized in that, The first modulator is a phase modulator and the second modulator is an intensity modulator; The electro-optic modulation device further includes a first coupler and a bias circuit; The common terminal of the first coupler is connected to the second modulator, the first branch terminal of the first coupler is connected to the first interferometer, and the second branch terminal of the first coupler is connected to the output terminal of the electro-optic frequency comb generator. The second modulator is also connected to the bias circuit; The electro-optic modulation device is further configured to output a third portion of the modulated optical signal to the bias circuit. The bias circuit is configured to output a bias voltage to the second modulator based on the third portion of the optical signal.

8. The electro-optic frequency comb generating device according to claim 4 or 5, characterized in that, The first modulator is a phase modulator and the second modulator is an intensity modulator; The electro-optic modulation device further includes a first coupler and a bias circuit; The common terminal of the first coupler is connected to the second modulator, the first branch terminal of the first coupler is coupled to the first interferometer, and the second branch terminal of the first coupler is connected to the bias circuit. The bias circuit is also connected to the second modulator; The second modulator is also connected to the output terminal of the electro-optic frequency comb generator; The electro-optic modulation device is further configured to output a third portion of the modulated optical signal to the bias circuit. The bias circuit is configured to output a bias voltage to the second modulator based on the third portion of the optical signal.

9. The electro-optic frequency comb generating device according to claim 4 or 5, characterized in that, The first modulator is a phase modulator and the second modulator is an intensity modulator; The electro-optic modulation device further includes a first coupler, a second coupler, and a bias circuit; The common terminal of the first coupler is connected to the second modulator, the first branch terminal of the first coupler is connected to the common terminal of the second coupler, and the second branch terminal of the first coupler is connected to the output terminal of the electro-optic frequency comb generator; the first branch terminal of the second coupler is connected to the first interferometer, and the second branch terminal of the second coupler is connected to the bias circuit. The bias circuit is also connected to the second modulator; The electro-optic modulation device is further configured to output a third portion of the modulated optical signal to the bias circuit. The bias circuit is configured to output a bias voltage to the second modulator based on the third portion of the optical signal.

10. The electro-optic frequency comb generating device according to any one of claims 1-3, characterized in that, The electro-optic modulation device includes: a first modulator, a second modulator, and a third modulator; the phase shifting circuit includes a first phase shifter and a second phase shifter; The first modulator, the second modulator, and the third modulator are cascaded sequentially between the output of the continuous laser and the output of the electro-optic frequency comb generator. The third modulator is also connected to the first interferometer. The first modulator is also connected to the microwave source. The second modulator is also connected to the first phase shifter; The third modulator is also connected to the second phase shifter; The first phase shifter is also connected to the microcontroller and the microwave source; The second phase shifter is also connected to the microcontroller and the microwave source.

11. The electro-optic frequency comb generating device according to claim 10, characterized in that, The first modulator and the second modulator are phase modulators, and the third modulator is an intensity modulator; The electro-optic frequency comb generator also includes a second interferometer and a second photodetector; The electro-optic modulation device also includes a third coupler; Wherein, the common end of the third coupler is connected to the second modulator, the first branch end of the third coupler is connected to the third modulator, and the second branch end of the third coupler is connected to the second interferometer; The second photodetector is connected to the second interferometer and the microcontroller; The electro-optic modulation device is configured to output the split signal from the optical signal modulated by the second modulator to the second interferometer; The second interferometer is configured to perform interference processing on the two delayed optical signals generated by the beam splitting signal to generate a second interference optical signal, wherein the two delayed optical signals of the beam splitting signal have different delays; The microcontroller is configured to adjust the microwave signal output by the phase shifter circuit based on the second detection result of the second photodetector on the second interference light signal.

12. A method for generating an electro-optic frequency comb, characterized in that, include: The optical signal output by the continuous laser is modulated by a microwave signal; The first part of the modulated optical signal is output. Two delayed optical signals are generated from the second part of the modulated optical signal. The two delayed optical signals of the second part of the optical signal are then subjected to interference processing to generate a first interference optical signal. The two delayed optical signals of the second part of the optical signal have different delays. The microwave signal is adjusted based on the first detection result of the first interference optical signal.

13. The method according to claim 12, characterized in that, The delay difference between the two delayed optical signals in the second part of the optical signal satisfies: θ c ω RF Δτ<λ, where θ c ω is the sum of the modulation depths of the phase modulator of the electro-optic modulation device. RF θ is the microwave modulation frequency of the microwave source, Δτ is the delay difference between the two delayed optical signals of the second part of the optical signal, and λ is the first minimum point of the zero-order Bessel function of the first kind; specifically θ c It can be represented as Where θ i The modulation depth of the i-th phase modulator can be represented as... V iRF V is the amplitude of the microwave signal applied to the i-th phase modulator. iπ Let be the half-wave voltage of the i-th phase modulator.

14. A light source, characterized in that, It includes a packaging structure, and an electro-optic frequency comb generator as described in any one of claims 1-11 packaged within the packaging structure.

15. An electronic device, characterized in that, It includes a circuit board and a light source as described in claim 14 connected to the circuit board.

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