Optoelectronic oscillator and signal processing method

Abstract

An optoelectronic oscillator (100) and a signal processing method, which relate to the technical field of optoelectronics. In the optoelectronic oscillator (100), an electro-optical modulator (110), an optoelectronic detector (120), a first filter (130) and a power divider (140) form an optoelectronic oscillation loop. Compared with a conventional single-passband filter, the first filter (130) in the optoelectronic oscillation loop has an additional low-frequency passband, and thus can excite a pulse train of the low-frequency passband and a pulse train of a bandpass band in the optoelectronic oscillation loop. Since the oscillation of a pulse signal can automatically narrow a pulse train to form an ultrashort pulse train, when the pulse train excited by the bandpass band has undergone pulse narrowing by means of an oscillation mechanism in the optoelectronic oscillation loop, the pulse train excited by the low-frequency passband may further undergo pulse narrowing, such that the optoelectronic oscillator (100) can generate a microwave pulse train which is shorter than that of a conventional optoelectronic oscillator, that is, an ultrashort microwave pulse train.

Description

A photoelectric oscillator and signal processing method

[0001] This application claims priority to Chinese Patent Application No. 202411181385.6, filed on August 26, 2024, entitled "An Optoelectronic Oscillator and Signal Processing Method", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of optoelectronic technology, and in particular to an optoelectronic oscillator and a signal processing method. Background Technology

[0003] A microwave pulse is a form of microwave pulse with an amplitude envelope, which, compared to a conventional pulse signal, has a microwave carrier with a fixed frequency within its pulse period. An ultrashort microwave pulse is a microwave pulse signal with a pulse width on the order of nanoseconds (ns), and it has wide applications in wireless sensing, medical imaging, pulse Doppler radar detection, and electronic warfare.

[0004] The microwave pulse sequence generation method based on an optoelectronic oscillator (OEO) is an optoelectronic technique that can output high-frequency microwave pulse sequences with ultrapure waveforms. However, the pulse width of the microwave pulses generated by this method is limited. Summary of the Invention

[0005] This application provides an optoelectronic oscillator and a signal processing method that can generate ultrashort microwave pulse signals.

[0006] In a first aspect, a photoelectric oscillator is provided, comprising: an electro-optic modulator, a photodetector, a first filter, a power divider, and a second filter; wherein, the electro-optic modulator is used to output a modulated optical pulse signal; the photodetector is used to convert the optical pulse signal into an electrical signal; the first filter is used to filter the electrical signal output by the photodetector, and the first filter includes a low-frequency passband and a band-pass passband; the power divider is used to divide the signal filtered by the first filter into a first signal and a second signal, the first signal being output to the electro-optic modulator and the second signal being output to the second filter; the second filter is used to filter the second signal and then output it.

[0007] Based on the first aspect of the optoelectronic oscillator, the electro-optic modulator, photodetector, first filter, and power divider constitute the optoelectronic oscillation loop. Compared to a conventional single-passband filter, the first filter in the optoelectronic oscillation loop adds a low-frequency passband, which can excite pulse sequences in both the low-frequency passband and bandpass passband within the optoelectronic oscillation loop. Since the oscillation of the pulse signal can automatically narrow the pulse sequence, forming an ultrashort pulse sequence, the pulse sequence excited by the bandpass passband, after passing through the oscillation mechanism within the optoelectronic oscillation loop and narrowing the pulse, will be further narrowed by the pulse sequence excited by the low-frequency passband. Therefore, the optoelectronic oscillator of the first aspect can generate a shorter microwave pulse sequence than a conventional optoelectronic oscillator, i.e., an ultrashort microwave pulse sequence.

[0008] Furthermore, by increasing the low-frequency passband, the pulse sequence excited within the photoelectric oscillation loop modulates the loop's loss, replacing the external periodic excitation signal and avoiding the need for external periodic excitation to modulate the loop's loss. Since the pulse sequence excited by the low-frequency passband naturally matches the length of the photoelectric oscillation loop, the requirement for the period of the external periodic excitation signal to be precisely matched with the loop's period is avoided, simplifying the photoelectric oscillator's operation. Simultaneously, the low-frequency passband pulse sequence excited by the photoelectric oscillation loop, through the loop's oscillation mechanism, narrows the pulses, resulting in a shorter pulse sequence than that generated by an external periodic excitation signal.

[0009] Optionally, the passband of the second filter corresponds to the bandpass of the first filter, or the passband of the second filter corresponds to the low-frequency passband of the first filter. Different signals can be output by setting the passband of the second filter.

[0010] When the passband of the second filter corresponds to the bandpass of the first filter, the center frequency of the passband of the second filter and the bandpass of the first filter are the same. At this time, the width of the passband of the second filter and the width of the bandpass of the first filter may not be exactly the same. For example, the width of the passband of the second filter may be wider or narrower than the width of the bandpass of the first filter. This application does not impose any restrictions on this.

[0011] When the passband of the second filter corresponds to the low-frequency passband of the first filter, the center frequency of the passband of the second filter and the low-frequency passband of the first filter are the same. At this time, the width of the passband of the second filter and the width of the low-frequency passband of the first filter may not be completely consistent. For example, the width of the passband of the second filter may be wider or narrower than the width of the low-frequency passband of the first filter. This application does not impose any restrictions on this.

[0012] Specifically, when the passband of the second filter corresponds to the bandpass of the first filter, the second filter is used to output a microwave pulse sequence; when the passband of the second filter corresponds to the low-frequency passband of the first filter, the second filter is used to output a pulse sequence. The difference between a microwave pulse sequence and a pulse sequence is that a microwave pulse sequence has a fixed-frequency microwave carrier wave within its pulse period, while a pulse sequence has no carrier wave within its pulse period. By adding a second filter within the opto-oscillator, both pulse sequence and microwave pulse sequence outputs can be achieved.

[0013] In one possible implementation, the opto-oscillator may further include an amplifier, the input of which is connected to the output of the first filter, and the output of which is connected to the input of the power divider. That is, the amplifier is connected between the first filter and the power divider, thus forming an opto-oscillation loop consisting of the electro-optic modulator, photodetector, first filter, power divider, second filter, and amplifier. The amplifier can be a single amplifier or multiple amplifiers connected in series or parallel. For example, the opto-oscillator may include amplifier #1 and amplifier #2, which are connected in series or parallel between the first filter and the power divider. Amplifier #1 amplifies the low-frequency passband filtered signal of the first filter, and amplifier #2 amplifies the bandpass filtered signal of the first filter.

[0014] Thus, the amplifier amplifies the power of the signal filtered by the first filter and outputs it to the power divider. The power divider distributes the power into two signals: the second signal is output, and the first signal is input back to the optoelectronic oscillation loop to enter the next cycle. Subsequently, the signal filtered by the first filter is amplified again by the amplifier and then distributed by the power divider. In this way, the optoelectronic oscillation loop is always kept oscillating, or in other words, the amplifier is always adjusted so that the gain in the optoelectronic oscillation loop is greater than the loss, exciting the optoelectronic oscillation loop to form pulse oscillations, thereby narrowing the pulse and obtaining an ultrashort microwave pulse sequence.

[0015] Optionally, in this embodiment, there can be multiple amplifiers located in different positions. For example, the input terminal of the amplifier is connected to the output terminal of the power divider, and the output terminal of the amplifier is connected to the input terminal of the electro-optic modulator. That is, the amplifier is connected between the power divider and the electro-optic modulator to amplify the first signal output by the power divider and output the amplified first signal to the electro-optic modulator. For example, the amplifier can also be located between the photodetector and the first filter, without limitation.

[0016] In one possible implementation, the photoelectric oscillator may further include an excitation source for outputting a single-pulse signal to an electro-optic modulator, which modulates the single-pulse signal into an optical pulse signal. The two input signals of the excitation source and the power divider can drive the electro-optic modulator through two independent input ports, such as connecting the output of the excitation source to input port #1 of the electro-optic modulator, and connecting the output of the power divider to input port #2 of the electro-optic modulator. The excitation source generates an initial excitation pulse and inputs it to the electro-optic modulator. This initial excitation pulse can be a single-pulse signal, which can excite pulse oscillation within the photoelectric oscillation loop. Thus, in this embodiment, the external excitation source of the photoelectric oscillator only needs to trigger a single pulse, eliminating the need for periodic pulse triggering, thereby simplifying the external excitation source.

[0017] Optionally, the excitation source and the power divider can be combined to drive the electro-optic modulator. For example, the excitation source and the power divider are combined and then connected to the input of the electro-optic modulator to improve the flexibility of setting the excitation source in the opto-oscillator.

[0018] In one possible implementation, the opto-oscillator may further include a laser for outputting an optical signal to an electro-optic modulator, which modulates a single-pulse signal onto the optical signal to output an optical pulse signal. The laser may be a device capable of emitting a continuous optical signal. The laser is used to generate a continuous optical signal and input it into the opto-oscillator loop, providing a light source for the loop.

[0019] Optionally, the electro-optic modulator is also used to modulate the first signal onto the optical signal, outputting an optical pulse signal. It can be understood that after the single-pulse signal generated by the excitation source drives the electro-optic modulator, the first signal output through the power divider subsequently pulse-modulates the photoelectric oscillation loop, maintaining oscillation within the loop.

[0020] Optionally, the electro-optic modulator is positioned in the low-bias operating point region or the high-bias operating point region of the modulation curve. When the electro-optic modulator is positioned in the low-bias operating point region or the high-bias operating point region of the modulation curve, the low-frequency passband in the first filter will move the operating point from the low-bias operating point region or the high-bias operating point region to the linear operating point (i.e., the midpoint of the modulation curve), thereby realizing linear modulation of the microwave pulse sequence.

[0021] Optionally, the optoelectronic oscillator may also include an optical fiber link. The optical fiber link includes optical fiber, and may also include optical amplifiers, optical attenuators, and optical filters.

[0022] Secondly, a signal processing method is provided, comprising: an electro-optic modulator outputting a modulated optical pulse signal; a photodetector converting the optical pulse signal into an electrical signal; a first filter filtering the electrical signal output from the photodetector, the first filter including a low-frequency passband and a band-pass passband; a power divider splitting the signal filtered by the first filter into a first signal and a second signal, the first signal being output to the electro-optic modulator, and the second signal being output to a second filter; and the second filter filtering the second signal and outputting the result.

[0023] In one possible implementation, the output of the second filter after filtering the second signal may include: the output of a microwave pulse sequence after filtering the second signal, wherein the passband of the second filter corresponds to the bandpass of the first filter; or, the output of a pulse sequence after filtering the second signal, wherein the passband of the second filter corresponds to the low-frequency passband of the first filter.

[0024] In one possible implementation, before the power divider splits the signal filtered by the first filter into a first signal and a second signal, the signal processing method may further include: an amplifier amplifying the signal filtered by the first filter.

[0025] In one possible implementation, the modulated optical pulse signal output by the electro-optic modulator may include: an excitation source outputting a single-pulse signal to the electro-optic modulator; and the electro-optic modulator modulating the single-pulse signal into an optical pulse signal.

[0026] Optionally, the modulated optical pulse signal output by the electro-optic modulator may also include: the laser outputting an optical signal to the electro-optic modulator. The electro-optic modulator modulates a single-pulse signal onto an optical signal, outputting an optical pulse signal.

[0027] In another possible implementation, the electro-optic modulator outputs a modulated optical pulse signal, which may also include: the electro-optic modulator modulates the first signal onto the optical signal and outputs an optical pulse signal.

[0028] Optionally, the electro-optic modulator is set in the low-bias operating point region or the high-bias operating point region of the modulation curve.

[0029] Furthermore, the technical effects of the method described in the second aspect can be referred to the technical effects of the photoelectric oscillator described in the first aspect, and will not be repeated here.

[0030] Thirdly, a communication device is provided, comprising: an antenna, and an optoelectronic oscillator as described in any of the embodiments of the first to second aspects, wherein the optoelectronic oscillator is used to output a microwave pulse sequence or pulse sequence, and the antenna is used to transmit the microwave pulse sequence or pulse sequence. The microwave pulse sequence may also be referred to as a microwave pulse signal, and the pulse sequence may also be referred to as a pulse signal.

[0031] In one possible implementation, the communication device may further include: a data modulation module for modulating the data signal to be transmitted onto a microwave pulse sequence or pulse sequence output by an optoelectronic oscillator, and an antenna for transmitting the microwave pulse sequence or pulse sequence.

[0032] In one possible implementation, the communication device may further include an amplifier for amplifying the data-modulated microwave pulse sequence or pulse sequence output by the data modulation module, and an antenna for transmitting the amplified microwave pulse sequence or pulse sequence output by the amplifier.

[0033] Furthermore, the technical effects of the communication device described in the third aspect can be referred to the technical effects of the photoelectric oscillator described in the first aspect, and will not be repeated here.

[0034] Fourthly, a microwave detection device is provided, comprising: an antenna, and an opto-oscillator as described in any of the embodiments of the first to second aspects, wherein the opto-oscillator is used to output a microwave pulse sequence or pulse sequence, and the antenna is used to transmit a microwave pulse sequence or pulse sequence. The microwave pulse sequence may also be referred to as a microwave pulse signal, and the pulse sequence may also be referred to as a pulse signal.

[0035] In one possible implementation, the microwave detection device may further include: an amplifier for amplifying a microwave pulse sequence or pulse sequence, and an antenna for transmitting the amplified microwave pulse sequence or pulse sequence output by the amplifier.

[0036] Furthermore, the technical effects of the microwave detection device described in the fourth aspect can be referenced by the technical effects of the photoelectric oscillator described in the first aspect, and will not be repeated here. Attached Figure Description

[0037] Figure 1 is a schematic diagram of an ultrashort microwave pulse signal;

[0038] Figure 2 is a schematic diagram of the microwave switching system;

[0039] Figure 3 is a schematic diagram of the DDS system;

[0040] Figure 4 is a schematic diagram of the system structure of active mode-locked OEO;

[0041] Figure 5 is a schematic diagram of the waveform of periodic loss modulation;

[0042] Figure 6 is a schematic diagram of the structure of an optoelectronic oscillator provided in an embodiment of this application;

[0043] Figure 7 is a schematic diagram of the transfer function of the first filter 130;

[0044] Figure 8 is a schematic diagram of the structure of an optoelectronic oscillator provided in an embodiment of this application;

[0045] Figure 9 is a schematic diagram of the structure of an optoelectronic oscillator provided in an embodiment of this application;

[0046] Figure 10 is a schematic diagram of the structure of an optoelectronic oscillator provided in an embodiment of this application;

[0047] Figure 11 is a schematic diagram of the output signal provided in an embodiment of this application;

[0048] Figure 12 is a schematic diagram of the operating bias point of the electro-optic modulator provided in an embodiment of this application;

[0049] Figure 13 is a schematic diagram of the operating bias point of the electro-optic modulator provided in the embodiment of this application;

[0050] Figure 14 is a schematic diagram of the output signal provided in an embodiment of this application;

[0051] Figure 15 is a flowchart illustrating the signal processing method provided in an embodiment of this application. Detailed Implementation

[0052] The terms "first" and "second" used in the embodiments of this application are only used to distinguish features of the same type and should not be construed as indicating relative importance, quantity, order, etc.

[0053] The terms "exemplary" or "for example" used in the embodiments of this application are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in this application should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of terms such as "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.

[0054] The terms "coupling" and "connection" used in the embodiments of this application should be interpreted broadly. For example, they can refer to a physical direct connection or an indirect connection achieved through electronic devices, such as a connection achieved through resistors, inductors, capacitors or other electronic devices.

[0055] For ease of understanding, some basic concepts involved in the embodiments of this application will be introduced below.

[0056] 1. Microwave pulse

[0057] A microwave pulse is a microwave form with an amplitude envelope that is a pulse. Compared to a conventional pulse signal, a microwave pulse has a microwave carrier with a fixed frequency within its pulse period.

[0058] A microwave pulse source is a signal source that generates microwave pulses, typically periodic microwave pulses. Periodic microwave pulses are called microwave pulse sequences.

[0059] Figure 1 is a schematic diagram of an ultrashort microwave pulse signal. As shown in Figure 1, an ultrashort microwave pulse signal is a microwave pulse signal with a pulse width on the order of nanoseconds (ns). Ultrashort microwave pulses have wide applications in wireless sensing, medical imaging, pulse Doppler radar detection, electronic warfare, and other fields.

[0060] For applications of ultrashort microwave pulse detection, high-frequency pulse sequences with ultra-narrow pulse width, low repetition frequency, and low timing jitter can improve the dynamic range of the system measurement and accurately achieve high-resolution target acquisition. In the field of medical imaging, high-frequency ultrashort microwave pulses are used to generate clear tissue images and can also be used to improve the accuracy of positioning and controlling the placement of therapeutic instruments.

[0061] Therefore, generating microwave signals with ultra-narrow pulse width, stable repetition frequency, low time jitter, and high frequency and low phase noise is the key to realizing ultrashort microwave pulse applications.

[0062] 2. Microwave Pulse Sequence Generation Methods in Electronic Technology

[0063] Microwave pulse sequence generation methods in electronic technology are usually based on pulse modulation and mixing techniques, and can specifically include two types: microwave switches and direct digital synthesizers (DDS).

[0064] Figure 2 is a schematic diagram of the microwave switch system. As shown in Figure 2(a), firstly, the microwave switch premodulates the continuous wave signal according to the time-domain pulse to generate a premodulated signal. The time-domain pulse is then conditioned by the time-domain pulse waveform conditioning module to obtain the conditioned time-domain pulse. The premodulated signal and the conditioned time-domain pulse are mixed at very low frequencies to generate a microwave pulse signal. Then, the microwave pulse signal is filtered and amplified in the waveform conditioning module, and finally, a narrow microwave pulse signal is output. The microwave pulse width generated by this scheme can reach the nanosecond level. The generation and transmission process of the electrical pulse signal used for modulation is easily affected by parasitic parameters. The actual generated pulse waveform often has poor purity, which can easily lead to distortions such as pulse broadening and tailing, resulting in corresponding distortion of the generated microwave pulse signal. As shown in Figure 2(b), due to the influence of parasitic parameters, the final output narrow microwave pulse signal has a long pulse tail.

[0065] Figure 3 shows a schematic diagram of the DDS system. As shown in Figure 3, firstly, a low-frequency carrier signal is generated through a comb spectrum generator and a Berkeley packet filter (BPF). The low-frequency carrier signal and the modulation pulse are synthesized by the DDS to generate a low-frequency pulse signal. Then, the low-frequency pulse signal is mixed with a high-frequency local oscillator, that is, the low-frequency pulse signal is mixed with the local oscillator signal generated by the dielectric oscillator, and then filtered by a filter to finally output a high-frequency microwave pulse signal. This method has the advantages of high speed, multiple modulation methods, and low cost. However, the DDS is limited by the frequency and phase noise of the working clock signal, resulting in disadvantages such as low output frequency, poor spurious performance, and small bandwidth. In addition, the mixing is required to achieve up-conversion of the low-frequency comb, so the generated microwave signal is also affected by the performance of the high-frequency local oscillator. Due to the limitations of the electronic local oscillator, the phase noise of the high-frequency local oscillator is relatively large, resulting in a correspondingly large phase noise in the generated microwave signal.

[0066] Furthermore, the limited bandwidth of microwave switching systems and DDS systems in electronic systems results in limited pulse widths, making it difficult to generate ultrashort microwave pulse signals.

[0067] 3. Optoelectronic oscillator

[0068] The method for generating ultrashort microwave pulse sequences based on optoelectronic oscillators (OEOs) is an optoelectronic technique. OEOs consist of a time-delay feedback loop connected by a closed optoelectronic link. Utilizing the high-quality Q-factor introduced by low-loss delay optical fibers, OEOs are widely used for generating various ultra-low phase noise microwave signals. Due to mode competition, typically only one mode exists within the oscillation passband, while other modes are suppressed; therefore, OEOs usually operate in a single-tone oscillation state.

[0069] Figure 4 shows a schematic diagram of the active mode-locked (OEO) system structure. As shown in Figure 4, an optical signal is input to the electro-optic modulator via a laser. After modulation by the electro-optic modulator, an optical pulse signal is output. The optical pulse signal is then input to a photodetector via an optical fiber, where it outputs an electrical signal. The electrical signal passes through a filter, an amplifier, and a power divider to output one microwave pulse signal. The other microwave pulse signal is amplitude modulated and then input to the electro-optic modulator, thus forming the OEO loop.

[0070] Electro-optic modulators utilize the electro-optic effect of certain electro-optic crystals, such as lithium niobate (LiNbO3), gallium arsenide (GaAs), and lithium tantalate (LiTaO3). The electro-optic effect occurs when a voltage is applied to an electro-optic crystal, causing a change in its refractive index. This change results in a change in the characteristics of the light transmitted through the crystal, thus modulating the phase, amplitude, intensity, and polarization state of the light signal. Photodetectors work by utilizing the change in conductivity of the irradiated material caused by radiation. Photodetectors convert optical signals into electrical signals. They can be categorized into photon detectors and thermal detectors.

[0071] In this OEO loop, active mode-locking technology is introduced, and a low-frequency single-modulation signal is used to periodically modulate the loss of the optoelectronic cavity, that is, an external periodic excitation signal is used to modulate the loss within the OEO loop. As shown in Figure 5, periodic loss modulation can periodically generate gain in the OEO loop. The optoelectronic oscillator can establish multiple phase-locked oscillation modes, thereby outputting a high-frequency microwave pulse sequence with ultrapure waveforms. The center frequency of the high-frequency microwave pulse sequence can be defined by the center frequency of the filter.

[0072] However, due to the limitation of modulation depth, active mode-locked OEO cannot take into account the advantages of high Q value and large bandwidth of OEO. The pulse width of the generated microwave pulse is inversely proportional to the bandwidth. Therefore, the pulse width of low repetition rate microwave pulses generated by active mode-locked OEO can only be reduced to the order of hundreds of nanoseconds, and it is impossible to generate ultrashort microwave pulse sequences, that is, microwave pulse sequences on the order of nanoseconds.

[0073] To address the aforementioned technical problems, the embodiments of this application propose the following technical solutions.

[0074] The technical solutions in this application will now be described with reference to the accompanying drawings.

[0075] In this embodiment, the optoelectronic oscillator, as a generator of ultra-short microwave pulse sequences, can be applied to microwave pulse detection scenarios, such as pulse radar and medical testing, or to ultra-wideband wireless communication scenarios, such as carrierless communication technology, including ultra-wideband (UWB), sensing base stations, and vehicle-mounted millimeter-wave radar.

[0076] For example, Figure 6 is a schematic diagram of the structure of an optoelectronic oscillator provided in an embodiment of this application. As shown in Figure 6, the optoelectronic oscillator 100 includes an electro-optic modulator 110, a photodetector 120, a first filter 130, a power divider 140, and a second filter 150. The output terminal of the electro-optic modulator 110 is connected to the input terminal of the photodetector 120. The output terminal of the photodetector 120 is connected to the input terminal of the first filter 130. The output terminal of the first filter 130 is connected to the input terminal of the power divider 140. The first output terminal of the power divider 140 is connected to the input terminal of the second filter 150, and the second output terminal of the power divider 140 is connected to the input terminal of the electro-optic modulator 110.

[0077] The electro-optic modulator 110, photodetector 120, first filter 130, power divider 140 and second filter 150 constitute an opto-optical oscillation loop, also known as an OEO loop or feedback loop. This application uses the opto-optical oscillation loop as an example for illustration.

[0078] The electro-optic modulator 110 is used to output modulated optical pulse signals. Optical pulse signals can also be called optical pulse sequences.

[0079] In the embodiments of this application, the electro-optic modulator 110 can be a device capable of modulating the phase, amplitude, intensity, and polarization state of an optical signal. For example, it can be a directly modulated laser (DML) or a semiconductor laser with an RF input port. Alternatively, it can be an externally modulated laser (EML), such as a Mach-Zehnder modulator (MZM) or an electro-absorption modulator (EAM), etc., and this application does not impose any limitations.

[0080] The photodetector 120 is used to convert the light pulse signal into an electrical signal and output the converted electrical signal to the first filter 130.

[0081] The photodetector 120 performs photoelectric conversion on the optical pulse signal to obtain an electrical signal, which can be a microwave signal.

[0082] The first filter 130 is used to filter the electrical signal output by the photodetector 120 and output the filtered signal to the power divider 140.

[0083] The first filter 130 may include a low-frequency passband and a band-pass passband. For example, Figure 7 is a schematic diagram of the transfer function of the first filter 130. As shown in Figure 7, the first filter 130 includes passband 1 (i.e., the aforementioned low-frequency passband) and passband 2 (i.e., the aforementioned band-pass passband). The frequency corresponding to passband 1 is lower than the frequency corresponding to passband 2. The frequency corresponding to passband 1 can be the frequency range of the signal filtered / allowed by passband 1, and the frequency corresponding to passband 2 can be the frequency range of the signal filtered / allowed by passband 2. It is understood that Figure 7 is only an example of the transfer function of the first filter 130, and the passband 1 and passband 2 of the first filter 130 can be other possible shapes, such as Gaussian shapes, which are not limited in this application.

[0084] The first filter 130 can be an electrical filter with dual passbands, also known as a dual-channel electrical filter. Alternatively, the first filter 130 can also be implemented by connecting single-passband / single-channel electrical filters in series or in parallel, such as a single-channel electrical filter with a low-frequency passband connected in series or in parallel with a single-channel electrical filter with a bandpass.

[0085] The low-frequency passband of the first filter 130 can filter low-frequency signals, or in other words, low-frequency signals can pass through normally, while high-frequency signals exceeding a set threshold are blocked or weakened. The threshold can be set based on experience and actual needs / specific applications. For example, the frequency range of the low-frequency passband can be 0 to f0, and signals with frequencies exceeding f0 are blocked or weakened. Here, f0 can be, for example, 2GHz, 3GHz, etc., without limitation.

[0086] In the embodiments of this application, the low-frequency passband can also be replaced with other possible expressions, such as low-pass passband, baseband passband, etc., without limitation.

[0087] The bandpass of the first filter 130 allows signals within a specific frequency range to pass through while blocking signals within other frequency ranges, or attenuating signals within other frequency ranges to extremely low levels. The specific frequency range can be set based on experience and actual needs / specific applications. For example, the bandpass frequency range can be f1 to f2, allowing signals with frequencies within f1 to f2 to pass through. f1 to f2 can be 6GHz to 10GHz, 5GHz to 10GHz, etc., without limitation.

[0088] The first filter 130 filters the electrical signal output by the photodetector 120 through the low-frequency passband and the band-pass passband to obtain two filtered signals, such as signal #1 after low-frequency passband filtering and signal #2 after band-pass passband filtering.

[0089] The power divider 140 is used to divide the signal filtered by the first filter 130 into a first signal and a second signal. The first signal is output to the electro-optic modulator 110, and the second signal is output to the second filter 150.

[0090] The power divider 140 has a power distribution function, such as distributing the power of the signal filtered by the first filter 130 to obtain a first signal and a second signal. This power distribution can be an equal distribution, or the first signal can have a higher power than the second signal, or vice versa; no limitation is made here. Both the first and second signals contain signals filtered by a low-frequency passband and a band-passband. For example, the first signal contains signal #1 filtered by the low-frequency passband and signal #2 filtered by the band-passband, and the second signal contains signal #1 filtered by the low-frequency passband and signal #2 filtered by the band-passband.

[0091] In the embodiments of this application, the first signal can also be replaced with other possible expressions, such as the first branch, the first signal branch, etc., and the second signal can also be replaced with other possible expressions, such as the second branch, the second signal branch, etc., without limitation.

[0092] The first signal is output to the electro-optic modulator 110, which modulates the first signal to obtain the aforementioned optical pulse signal, thereby forming an opto-optical oscillation loop between the photodetector 120, the first filter 130, the power divider 140, and the second filter 150.

[0093] The second filter 150 is used to filter the second signal before outputting it.

[0094] In this embodiment, the second filter 150 can be a single-passband / single-channel filter used to filter the signal after low-frequency passband filtering by the first filter 130, or to filter the signal after bandpass filtering by the first filter 130. By adding the second filter 150 to the output signal port of the opto-oscillator 100, both pulse sequence and microwave pulse sequence outputs can be achieved.

[0095] Optionally, the passband of the second filter 150 corresponds to the bandpass of the first filter 130, or the passband of the second filter 150 corresponds to the low-frequency passband of the first filter 130. Different signals can be output by setting the passband of the second filter 150.

[0096] Specifically, when the passband of the second filter 150 corresponds to the bandpass of the first filter 130, the second filter 150 is used to output a microwave pulse sequence. When the passband of the second filter 150 corresponds to the low-frequency passband of the first filter 130, the second filter 150 is used to output a pulse sequence.

[0097] When the passband of the second filter 150 corresponds to the bandpass of the first filter 130, the center frequencies of the passband of the second filter 150 and the bandpass of the first filter 130 are the same. At this time, the width of the passband of the second filter 150 and the width of the bandpass of the first filter 130 may not be exactly the same. For example, the width of the passband of the second filter 150 may be wider or narrower than the width of the bandpass of the first filter 130. This application does not impose any restrictions on this.

[0098] When the passband of the second filter 150 corresponds to the low-frequency passband of the first filter 130, the center frequencies of the passband of the second filter 150 and the low-frequency passband of the first filter 130 are the same. At this time, the width of the passband of the second filter 150 and the width of the low-frequency passband of the first filter 130 may not be completely consistent. For example, the width of the passband of the second filter 150 may be wider or narrower than the width of the low-frequency passband of the first filter 130. This application does not impose any restrictions on this.

[0099] If the passband of the second filter 150 corresponds to the bandpass of the first filter 130, then the second filter 150 outputs a microwave pulse sequence filtered by the bandpass of the first filter 130, and the center frequency of the carrier of the microwave pulse sequence is the center frequency of the bandpass. If the passband of the second filter 150 corresponds to the low-frequency passband of the first filter 130, then the output is a pulse sequence filtered by the low-frequency passband of the first filter 130. Since the signal output by the second filter 150 is periodic, that is, it outputs a periodic microwave pulse sequence or pulse sequence, the electrical signal output by the second filter 150 is referred to here as a microwave pulse sequence or pulse sequence. Of course, the microwave pulse sequence can also be replaced with a microwave pulse signal, and the pulse sequence can be replaced with a pulse signal; there are no restrictions.

[0100] The difference between a microwave pulse sequence and a pulse sequence is that a microwave pulse sequence has a microwave carrier with a fixed frequency within the pulse period, while a pulse sequence has no carrier within the pulse period.

[0101] For example, as shown in Figure 7, the first filter 130 includes passband 1 (i.e., the aforementioned low-frequency passband) and passband 2 (i.e., the aforementioned band-pass passband). When the second filter 150 is in passband 2, it outputs a microwave pulse sequence. When the second filter 150 is in passband 1, it outputs a pulse sequence.

[0102] By adjusting the bandwidth of the first filter 130 and the second filter 150, the pulse width of the microwave pulse sequence or pulse sequence can be reduced.

[0103] Additionally, the optoelectronic oscillator 100 may also include an optical fiber link. The optical fiber link includes optical fiber and may also include some or all of an optical amplifier, an optical attenuator, and an optical filter.

[0104] Thus, in the aforementioned opto-oscillation loop, the first filter 130, compared to a conventional single-passband filter, adds a low-frequency passband, which can excite pulse sequences of both the low-frequency passband and the bandpass passband within the opto-oscillation loop. Since the oscillation of the pulse sequence can automatically narrow the pulse sequence, forming an ultra-short pulse sequence, the pulse sequence excited by the low-frequency passband will be further narrowed after the bandpass passband pulse sequence undergoes the loop oscillation mechanism to narrow the pulse. Therefore, the opto-oscillator in this embodiment can generate a shorter microwave pulse sequence than a conventional active mode-locked (OEO) pulse sequence, i.e., an ultra-short microwave pulse sequence.

[0105] Furthermore, by increasing the low-frequency passband, the pulse sequence excited within the photoelectric oscillation loop modulates the loop's loss, replacing the external periodic excitation signal. This avoids the need for external periodic excitation signals to modulate the loop's loss. Since the pulse sequence excited by the low-frequency passband naturally matches the length of the photoelectric oscillation loop, the requirement for the period of the external periodic excitation signal to be precisely matched with the loop's period is avoided, simplifying the photoelectric oscillator's operation. Simultaneously, the low-frequency passband pulse sequence excited by the photoelectric oscillation loop, through the loop's oscillation mechanism, narrows the pulses, resulting in a shorter pulse sequence than that generated by an external periodic excitation signal.

[0106] In one possible implementation, Figure 8 is a second schematic diagram of the structure of an optoelectronic oscillator provided in an embodiment of this application. As shown in Figure 8, the optoelectronic oscillator 100 may further include an amplifier 160. The input terminal of the amplifier 160 is connected to the output terminal of the first filter 130, and the output terminal of the amplifier 160 is connected to the input terminal of the power divider 140. That is, the amplifier 160 is connected between the first filter 130 and the power divider 140. The amplifier 160 is used to amplify the signal filtered by the first filter 130 and output the amplified signal to the power divider 140. The power divider 140 then divides the amplified signal into a first signal and a second signal.

[0107] The electro-optic modulator 110, photodetector 120, first filter 130, power divider 140, second filter 150 and amplifier 160 constitute an opto-optical oscillation loop.

[0108] Amplifier 160 can be a single amplifier or multiple amplifiers connected in series or parallel. For example, amplifier 160 may include amplifier 1601 (not shown in Figure 8) and amplifier 1602 (not shown in Figure 8), which are connected in series or parallel between the first filter 130 and the power divider 140. Amplifier 1601 is used to amplify the low-frequency passband filtered signal of the first filter 130, and amplifier 1602 is used to amplify the bandpass filtered signal of the first filter 130.

[0109] Optionally, the input terminal of amplifier 160 is connected to the output terminal of power divider 140, and the output terminal of amplifier 160 is connected to the input terminal of electro-optic modulator 110. That is, amplifier 160 is connected between power divider 140 and electro-optic modulator 110 to amplify the first signal output from power divider 140 and output the amplified first signal to electro-optic modulator 110. In this embodiment, there may be multiple amplifiers 160, and they may be located in different positions. This is just one example; for instance, the amplifier may also be located between photodetector 120 and first filter 130, without limitation.

[0110] Thus, amplifier 160 amplifies the power of the signal filtered by the first filter 130 and outputs it to power divider 140. Power divider 140 distributes the power into two signals: the second signal is output, and the first signal is input back to the photoelectric oscillation loop for the next cycle. Subsequently, the signal filtered by the first filter 130 is again amplified by amplifier 160 and then distributed by power divider 140. In this way, pulse oscillation is maintained within the photoelectric oscillation loop, or in other words, amplifier 140 is always adjusted so that the gain within the photoelectric oscillation loop is greater than the loss, exciting the photoelectric oscillation loop to form pulse oscillation, thereby narrowing the pulse and obtaining an ultrashort microwave pulse sequence.

[0111] In one possible implementation, Figure 9 is a schematic diagram of the structure of an optoelectronic oscillator provided in an embodiment of this application. As shown in Figure 9(a), the optoelectronic oscillator 100 may further include an excitation source 170. The excitation source 170 is used to output a single-pulse signal to the electro-optic modulator 110, and the electro-optic modulator 110 is used to modulate the single-pulse signal into an optical pulse signal.

[0112] The two input signals of the excitation source 170 and the power divider 140 can drive the electro-optic modulator 110 through two independent input ports. For example, the output of the excitation source 170 is connected to input port #1 of the electro-optic modulator 110, and the output of the power divider 140 is connected to input port #2 of the electro-optic modulator 110. The excitation source 170 is used to generate an initial excitation pulse and input it to the electro-optic modulator 110. This initial excitation pulse can be a single pulse signal, which can excite pulse oscillation within the photoelectric oscillation loop. The output of the excitation source 170 drives the electro-optic modulator 110. Therefore, the amplitude of the single pulse signal needs to be sufficient to enable amplitude modulation by the electro-optic modulator 110.

[0113] Thus, the external excitation source of the photoelectric oscillator in this embodiment only needs to trigger one pulse, and does not require periodic pulse triggering, which simplifies the external excitation source.

[0114] Optionally, the excitation source 170 and the power divider 140 can be combined to drive the electro-optic modulator 110. For example, as shown in FIG9(b), the excitation source 170 and the power divider 140 are combined and then connected to the input terminal of the electro-optic modulator 110 to improve the flexibility of setting the excitation source 170 in the opto-oscillator 100.

[0115] In one possible implementation, Figure 10 is a schematic diagram of the structure of an optoelectronic oscillator provided in an embodiment of this application. As shown in Figure 10, the optoelectronic oscillator 100 may further include a laser 180. The laser 180 is used to output an optical signal to the electro-optic modulator 110, and the electro-optic modulator 110 is used to modulate a single-pulse signal onto the optical signal to output an optical pulse signal.

[0116] Laser 180 can be a device capable of emitting continuous optical signals. Laser 180 is used to generate continuous optical signals and input them into an optoelectronic oscillation loop to provide a light source for the optoelectronic oscillation loop.

[0117] In another possible implementation, the electro-optic modulator 110 is also used to modulate the first signal onto the optical signal, outputting an optical pulse signal. It can be understood that after the single-pulse signal generated by the excitation source 170 drives the electro-optic modulator 110, the first signal output by the power divider 140 subsequently performs pulse modulation on the photoelectric oscillation loop.

[0118] The following lists the possible output signals generated after passing through the photoelectric oscillation loop.

[0119] For example, Figure 11 is a schematic diagram of the output signal provided in an embodiment of this application. Taking the generation of an 8GHz frequency ns-level microwave pulse sequence as an example, the signal output by the power divider 140 through the optoelectronic oscillation loop is shown in Figure 11(a)-(d). In Figure 11(a), the waveform of the periodic microwave pulse sequence is shown, which is the waveform corresponding to the bandpass in the first filter 130. In Figure 11(b), the waveform of a single microwave pulse is shown.

[0120] Figure 11(c) shows the spectrum of the periodic pulse sequence, which is the superposition of the low-pass and band-pass spectra. Figure 11(d) shows the periodic spectral components. The signal output by the power divider 140 has a dual-passband spectrum, namely a low-pass spectrum and a band-pass spectrum, and the spectrum consists of discrete periodic lines. The low-pass spectrum component is a periodic pulse sequence, and the band-pass spectrum is a periodic microwave pulse sequence. Therefore, the total signal is the superposition of the two spectra, which is an asymmetric microwave pulse sequence.

[0121] In Figure 11(e), the signal is filtered by the second filter 150. In Figure 11(f), the single microwave pulse sequence is filtered by the second filter 150. As shown in Figures 11(e) and (f), by filtering out the bandpass spectrum by the second filter 150, a symmetrical periodic microwave pulse sequence can be output.

[0122] Different settings of the operating point of the electro-optic modulator 110 will result in different optical pulse signals in the photoelectric oscillation loop, which in turn will lead to different microwave pulse sequences output by the power divider 140.

[0123] Optionally, the electro-optic modulator 110 is positioned in the low-bias operating point region or the high-bias operating point region of the modulation curve. The low-bias operating point region can be the low-bias operating point and its vicinity on the modulation curve, and the high-bias operating point region can be the high-bias operating point and its vicinity on the modulation curve. The vicinity of the low-bias operating point can be defined by the abscissa of the low-bias operating point on the modulation curve. For example, Figure 12 is a schematic diagram of the operating bias point of the electro-optic modulator provided in this embodiment. As shown in Figure 12, the coordinates of the low-bias operating point A are (x1, y1). The vicinity of the low-bias operating point can be the region formed by B(x1-x*r, y2) and C(x1+x*r, y3) on the modulation curve. The vicinity of the high-bias operating point is similar to that of the low-bias operating point. Here, r can be the half-wave voltage, i.e., Vπ, or it can be a value set according to actual needs without limitation. x can be any ratio set according to actual needs, such as 10%, 15%, 20%, etc., without limitation. Of course, the area near the high-bias operating point or the low-bias operating point can also be determined by other methods, and this application does not impose any restrictions on this.

[0124] When the electro-optic modulator 110 is set in the low-bias operating point region or the high-bias operating point region of the modulation curve, the low-frequency passband in the first filter 130 will move the operating point from the low-bias operating point region or the high-bias operating point region to the linear operating point (i.e., the midpoint of the modulation curve). Figure 13 is a schematic diagram of the operating bias point of the electro-optic modulator provided in this embodiment of the application. For ease of explanation, the pulse sequence of the low-frequency passband in the first filter 130 is represented by rectangular pulses. As shown in Figure 13(a), when the electro-optic modulator 110 is set in the low-bias operating point of the modulation curve, the rectangular pulses in the low-frequency passband move the operating point from the low-bias operating point to the linear operating point. As shown in Figure 13(b), when the electro-optic modulator 110 is set in the high-bias operating point of the modulation curve, the rectangular pulses in the low-frequency passband move the operating point from the high-bias operating point to the linear operating point, realizing linear modulation of the microwave pulse sequence.

[0125] For example, Figure 14 is a schematic diagram of the output signal provided in an embodiment of this application. Figure 14(a) shows the periodic signal waveform (including microwave pulse sequence and pulse sequence) output by the power divider 140 when the electro-optic modulator 110 operates at and near the low bias operating point. Figure 14(b) shows the single signal waveform (including microwave pulse sequence and pulse sequence) output by the power divider 140 when the electro-optic modulator 110 operates at and near the low bias operating point. Figure 14(c) shows the microwave pulse sequence output by the second filter 150 when the electro-optic modulator 110 operates at and near the low bias operating point. Figure 14(d) shows the periodic signal waveform (including microwave pulse sequence and pulse sequence) output by the power divider 140 when the electro-optic modulator 110 operates at and near the high bias operating point. Figure 14(e) shows the single signal waveform (including microwave pulse sequence and pulse sequence) output by the power divider 140 when the electro-optic modulator 110 operates at and near the high bias operating point. Figure 14(f) shows the microwave pulse sequence output by the second filter 150 when the electro-optic modulator 110 operates at and near the high bias operating point. As shown in Figures 14(a), (b), (d), and (e), the signal / sequence output by the power divider 140 is different when the electro-optic modulator 110 operates at different bias points. As shown in Figures 14(c) and (f), although the electro-optic modulator 110 operates at different bias points, the microwave pulse sequence filtered out by the second filter 150 after the signal / sequence output by the power divider 140 is the same.

[0126] Thus, through the second filter 150, the electro-optic modulator 110 can operate in the low-bias operating point region or the high-bias operating point region of the modulator curve, outputting the same microwave pulse sequence.

[0127] The photoelectric oscillator provided in the embodiments of this application has been described in detail above with reference to Figures 6-14. The signal processing method performed by the photoelectric oscillator is described in detail below with reference to Figure 15.

[0128] For example, Figure 15 is a schematic flowchart of a signal processing method provided in an embodiment of this application. The flowchart of the signal processing method may include:

[0129] S1501, the electro-optic modulator outputs modulated optical pulse signals.

[0130] S1502, the photodetector converts light pulse signals into electrical signals.

[0131] S1503, the first filter filters the electrical signal output by the photodetector.

[0132] The first filter may include a low-frequency passband and a band-pass passband.

[0133] S1504, the power divider splits the signal filtered by the first filter into a first signal and a second signal. The first signal is output to the electro-optic modulator, and the second signal is output to the second filter.

[0134] S1505, the second filter outputs the filtered second signal.

[0135] In one possible implementation, S1505 may include: the second filter filters the second signal and outputs a microwave pulse sequence, the passband of the second filter corresponding to the bandpass of the first filter; or, the second filter filters the second signal and outputs a pulse sequence, the passband of the second filter corresponding to the low-frequency passband of the first filter.

[0136] Optionally, prior to S1504, the signal processing method may further include: amplifying the signal filtered by the first filter using an amplifier.

[0137] In one possible implementation, S1501 may include: an excitation source outputting a single-pulse signal to an electro-optic modulator. The electro-optic modulator modulates the single-pulse signal into an optical pulse signal.

[0138] Optionally, S1501 may also include: a laser outputting an optical signal to an electro-optic modulator; the electro-optic modulator modulating a single-pulse signal onto the optical signal and outputting an optical pulse signal.

[0139] In another possible implementation, S1501 may also include: an electro-optic modulator modulates the first signal onto the optical signal and outputs an optical pulse signal.

[0140] Optionally, the electro-optic modulator is set in the low-bias operating point region or the high-bias operating point region of the modulation curve.

[0141] Furthermore, the specific implementation of this signal processing method can be found in the relevant introduction to the aforementioned photoelectric oscillator, and the technical effects of this signal processing method can be found in the technical effects of the aforementioned photoelectric oscillator, which will not be elaborated here.

[0142] It should be understood that in the various embodiments of this application, the order of the above-mentioned processes does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0143] Those skilled in the art will recognize that the modules and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0144] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and modules described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0145] In the embodiments presented in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of modules is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple modules or components may be combined or integrated into another device, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between devices or modules may be electrical, mechanical, or other forms.

[0146] The modules described as separate components may or may not be physically separate. The components shown as modules may or may not be physical modules; that is, they may be located in one device or distributed across multiple devices. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs.

[0147] In addition, the functional modules in the various embodiments of this application can be integrated into one device, or each module can exist physically separately, or two or more modules can be integrated into one device.

[0148] In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, firmware, or any combination thereof. When implemented using software programs, implementation can be, in whole or in part, in the form of a computer program product. This computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium accessible to a computer or a data storage device containing one or more servers, data centers, etc., that can be integrated with the medium. The available media can be magnetic media (e.g., floppy disks, hard disks, magnetic tapes), optical media (e.g., DVDs), or semiconductor media (e.g., solid-state disks (SSDs)).

[0149] The photoelectric oscillator in this application embodiment can be a device for realizing wireless communication functions. For example, this application embodiment provides a communication device including: an antenna and a photoelectric oscillator. The photoelectric oscillator is used to output a microwave pulse sequence or pulse sequence, and the antenna is used to transmit the microwave pulse sequence or pulse sequence. The microwave pulse sequence can also be referred to as a microwave pulse signal, and the pulse sequence can also be referred to as a pulse signal.

[0150] In one possible implementation, the communication device may further include: a data modulation module and an amplifier, wherein the data modulation module is used to modulate the data signal to be transmitted onto a microwave pulse sequence or pulse sequence output by an optoelectronic oscillator, the amplifier is used to amplify the data-modulated microwave pulse sequence or pulse sequence output by the data modulation module, and the antenna is used to transmit the amplified microwave pulse sequence or pulse sequence output by the amplifier.

[0151] In one possible implementation, the optoelectronic oscillator in this embodiment can be applied to a terminal or used in a chip within the terminal. The terminal can be a UE, access terminal, terminal unit, terminal station, mobile station, mobile station, remote station, remote terminal, mobile device, wireless communication device, terminal agent, or terminal device in a future network or a future evolved public land mobile network (PLMN). Access terminals can be cellular phones, cordless phones, session initiation protocol (SIP) phones, wireless local loop (WLL) stations, personal digital assistants (PDAs), handheld devices with wireless communication capabilities, computing devices or other processing devices connected to a wireless modem, in-vehicle devices or wearable devices, virtual reality (VR) terminal devices, augmented reality (AR) terminal devices, wireless terminals in industrial control, wireless terminals in self-driving, wireless terminals in remote medical care, wireless terminals in smart grids, wireless terminals in transportation safety, wireless terminals in smart cities, wireless terminals in smart homes, etc. Optionally, the photoelectric oscillator can be mobile or fixed.

[0152] In one possible implementation, the optoelectronic oscillator in this embodiment can be applied to a network device that communicates with a terminal device. This network device may include a transmission reception point (TRP), a base station, a remote radio unit (RRU) or baseband unit (BBU) (also known as a digital unit (DU)) of a split base station, a satellite, a drone, a broadband network gateway (BNG), an aggregation switch, non-3GPP access equipment, a relay station, or an access point, etc.

[0153] In addition, a base station can be a base transceiver station (BTS) in a global system for mobile communication (GSM) or code division multiple access (CDMA) network, an NB (Node B) in a wideband code division multiple access (WCDMA) network, an eNB or eNodeB (evolutionary Node B) in LTE, a radio controller in a cloud radio access network (CRAN) scenario, or a base station in a 5G communication system (such as a next-generation Node B (gNodeB, gNB)), or a base station in a future evolved network, etc., without being specifically limited here.

[0154] The photoelectric oscillator in this application embodiment can be a device for realizing microwave detection function. Exemplarily, this application embodiment also provides a microwave detection device, which includes: an antenna and a photoelectric oscillator, wherein the photoelectric oscillator is used to output a microwave pulse sequence or pulse sequence, and the antenna is used to transmit a microwave pulse sequence or pulse sequence. The microwave pulse sequence can also be referred to as a microwave pulse signal, and the pulse sequence can also be referred to as a pulse signal.

[0155] In one possible implementation, the microwave detection device may further include: an amplifier for amplifying a microwave pulse sequence or pulse sequence, and an antenna for transmitting the amplified microwave pulse sequence or pulse sequence.

[0156] Furthermore, the communication architecture and business scenarios described in the embodiments of this application are for the purpose of more clearly illustrating the technical solutions of the embodiments of this application, and do not constitute a limitation on the technical solutions proposed in the embodiments of this application. As those skilled in the art will know, with the evolution of communication architecture and the emergence of new business scenarios, the technical solutions proposed in the embodiments of this application are also applicable to similar technical problems.

[0157] 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. A photoelectric oscillator, characterized in that, include: Electro-optic modulator, photodetector, first filter, power divider, and second filter; among which, The electro-optic modulator is used to output modulated optical pulse signals; The photodetector is used to convert the optical pulse signal into an electrical signal; The first filter is used to filter the electrical signal output by the photodetector, and the first filter includes a low-frequency passband and a band-pass passband; The power divider is used to divide the signal filtered by the first filter into a first signal and a second signal. The first signal is output to the electro-optic modulator, and the second signal is output to the second filter. The second filter is used to filter the second signal before outputting it.

2. The photoelectric oscillator according to claim 1, characterized in that, The passband of the second filter corresponds to the bandpass of the first filter, or the passband of the second filter corresponds to the low-frequency passband of the first filter.

3. The photoelectric oscillator according to claim 2, characterized in that, When the passband of the second filter corresponds to the bandpass of the first filter, the second filter is used to output a microwave pulse sequence; when the passband of the second filter corresponds to the low-frequency passband of the first filter, the second filter is used to output a pulse sequence.

4. The photoelectric oscillator according to any one of claims 1 to 3, characterized in that, It also includes an amplifier, the input of which is connected to the output of the first filter, and the output of which is connected to the input of the power divider.

5. The photoelectric oscillator according to any one of claims 1 to 4, characterized in that, It also includes an excitation source, which is used to output a single pulse signal to the electro-optic modulator, and the electro-optic modulator is used to modulate the single pulse signal into the optical pulse signal.

6. The photoelectric oscillator according to claim 5, characterized in that, It also includes a laser, which is used to output an optical signal to the electro-optic modulator, and the electro-optic modulator is used to modulate the single-pulse signal onto the optical signal to output the optical pulse signal.

7. The photoelectric oscillator according to claim 6, characterized in that, The electro-optic modulator is also used to modulate the first signal onto the optical signal and output the optical pulse signal.

8. The photoelectric oscillator according to any one of claims 1-7, characterized in that, The electro-optic modulator is positioned in the low-bias operating point region or the high-bias operating point region of the modulation curve.

9. A signal processing method, characterized in that, include: The electro-optic modulator outputs a modulated optical pulse signal. The photodetector converts the optical pulse signal into an electrical signal; The first filter filters the electrical signal output by the photodetector, and the first filter includes a low-frequency passband and a band-pass passband; The power divider splits the signal filtered by the first filter into a first signal and a second signal. The first signal is output to the electro-optic modulator, and the second signal is output to the second filter. The second filter outputs the filtered second signal.

10. The method according to claim 9, characterized in that, The output of the second filter after filtering the second signal includes: The second filter outputs a microwave pulse sequence after filtering the second signal, and the passband of the second filter corresponds to the bandpass of the first filter; or, The second filter outputs a pulse sequence after filtering the second signal, and the passband of the second filter corresponds to the low-frequency passband of the first filter.

11. The method according to claim 9 or 10, characterized in that, Before the power divider splits the signal filtered by the first filter into a first signal and a second signal, the method further includes: The amplifier amplifies the signal filtered by the first filter.

12. The method according to any one of claims 9 to 11, characterized in that, The electro-optic modulator outputs a modulated optical pulse signal, including: The excitation source outputs a single-pulse signal to the electro-optic modulator; The electro-optic modulator modulates the single-pulse signal into the optical pulse signal.

13. The method according to claim 12, characterized in that, The electro-optic modulator outputs a modulated optical pulse signal, which further includes: The laser outputs an optical signal to the electro-optic modulator; The electro-optic modulator modulates the single-pulse signal onto the optical signal and outputs the optical pulse signal.

14. The method according to claim 13, characterized in that, The electro-optic modulator outputs a modulated optical pulse signal, which further includes: The electro-optic modulator modulates the first signal onto the optical signal and outputs the optical pulse signal.

15. The method according to any one of claims 9-14, characterized in that, The electro-optic modulator is positioned in the low-bias operating point region or the high-bias operating point region of the modulation curve.

16. A communication device, characterized in that, The device includes: an optoelectronic oscillator as described in any one of claims 1-8, a data modulation module, an amplifier, and an antenna; The opto-oscillator is used to output a microwave pulse sequence or a pulse sequence; The data modulation module is used to modulate the data signal to be transmitted onto the microwave pulse sequence or pulse sequence output by the photoelectric oscillator; The antenna is used to transmit the microwave pulse sequence or pulse sequence.

17. The communication device according to claim 16, characterized in that, It also includes an amplifier for amplifying the microwave pulse sequence or pulse sequence.

18. A microwave detection device, characterized in that, The device comprises: a photoelectric oscillator as described in any one of claims 1-8, and an antenna; The opto-oscillator is used to output a microwave pulse sequence or a pulse sequence; The antenna is used to transmit the microwave pulse sequence or pulse sequence.

19. The microwave detection device according to claim 18, characterized in that, It also includes an amplifier for amplifying the microwave pulse sequence or pulse sequence.

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