Frequency multiplication triangular waveform generation system and method

Abstract

The invention provides a frequency doubling triangular waveform generation system and method, and relates to the technical field of optical communication, the frequency doubling triangular waveform generation system comprises a first continuous light laser, a second continuous light laser, a first intensity modulator, a wavelength division multiplexer, a second intensity modulator, a radio frequency signal generator, an electric attenuator and a photoelectric detector; the first continuous light laser is connected with the wavelength division multiplexer; the output end of the second continuous light laser is connected with a light input interface of the first intensity modulator, and the output end of the first intensity modulator is connected with the wavelength division multiplexer; the output end of the wavelength division multiplexer is connected with an optical input interface of the second intensity modulator, and the output end of the second intensity modulator is connected with the input end of the photoelectric detector; the output end of the radio frequency signal generator is connected with the radio frequency input interface of the first intensity modulator, and the output end of the radio frequency signal generator is connected with the radio frequency input interface of the second intensity modulator through the electric attenuator. The device is low in cost, simple in structure and easy to operate.

Description

Technical Field

[0001] The present invention relates to the field of optical communication technology, and in particular to a frequency-doubled triangle waveform generation system and method. Background Art

[0002] High-speed microwave signals are widely used in modern radars or antennas, sensor networks, radio frequency communication systems, electronic equipment test and measurement and other fields. Therefore, the generation of high-frequency microwave signals has always been a research hotspot. The development of human society has put forward higher requirements for the frequency of microwave signals, such as the millimeter wave communication technology used in the fifth generation of mobile communication technology. Compared with the traditional method of generating microwave signals electrically, the method of generating microwave signals with optical assistance has the advantages of large bandwidth, anti-electromagnetic interference, and high speed.

[0003] Related technologies propose methods for spectrum shaping and frequency-time mapping of wide-spectrum light sources, which produce triangular microwave signals with adjustable repetition frequency. However, the cost of using wide-spectrum light sources is too high, the synthesis of triangular waveforms with different repetition frequencies requires different optical fiber lengths, and the generated signal pulse width is relatively narrow.

[0004] By analyzing the frequency components of triangular microwave signals, researchers have realized that triangular waves are composed of a series of odd-order sinusoidal signals, and the energy is concentrated in the first-order and third-order harmonics. It is only necessary to generate a signal that satisfies the amplitude and phase of the first-order and third-order harmonics of the triangular wave to generate a microwave signal that is approximately triangular. In the related art, a method of using a continuous light source as a carrier for external modulation is proposed to generate a frequency-doubled triangular signal. This method is based on an integrated modulator dual-parallel Mach-Zehnder modulator (DP-MZM) to externally modulate continuous light, in which one of the two sub-modulators operates at the minimum bias point and the main modulator operates at the orthogonal bias point; however, the method requires the use of an electrical tripler to triple the frequency of a radio frequency signal input to the DP-MZM to meet the system requirements, so that the frequency of the signal generated by the system is limited by the bandwidth of the electrical tripler.

[0005] Broad-spectrum light sources and continuous light sources are widely used in the generation of microwave signals, but there are problems: the broad-spectrum light source is generated by a mode-locked laser, the repetition frequency of the light pulse is low, and the time domain repetition period of the pulse is long, which is not conducive to the generation of microwave signals with high repetition frequency; most of the external modulation systems using continuous light sources as carriers cannot generate frequency-doubled signals. Therefore, in the prior art, it is difficult to generate frequency-doubled triangular waveform signals. Summary of the invention

[0006] The technical solution of the present invention aims to provide a system and method for generating a frequency-doubled triangle waveform, so as to solve the problem that the frequency-doubled triangle waveform signal is difficult to generate in the prior art.

[0007] The embodiment of the present invention provides the following technical solutions:

[0008] An embodiment of the present invention provides a frequency-doubled triangle waveform generation system, comprising:

[0009] A first continuous light laser, a second continuous light laser, a first intensity modulator, a wavelength division multiplexer, a second intensity modulator, a radio frequency signal generator, an electric attenuator, and a photodetector;

[0010] Among them, the output end of the first continuous light laser is connected to the first input end of the wavelength division multiplexer; the output end of the second continuous light laser is connected to the optical input interface of the first intensity modulator, and the output end of the first intensity modulator is connected to the second input end of the wavelength division multiplexer; the output end of the wavelength division multiplexer is connected to the optical input interface of the second intensity modulator, and the output end of the second intensity modulator is connected to the input end of the photodetector; the output end of the radio frequency signal generator is connected to the radio frequency input interface of the first intensity modulator, and the output end of the radio frequency signal generator is connected to the radio frequency input interface of the second intensity modulator through the electrical attenuator.

[0011] Optionally, the output end of the first continuous light laser is connected to the first input end of the wavelength division multiplexer via an optical fiber;

[0012] The output end of the second continuous light laser is connected to the optical input interface of the first intensity modulator, and the output end of the first intensity modulator is connected to the second input end of the wavelength division multiplexer through optical fibers respectively;

[0013] The output end of the wavelength division multiplexer and the optical input interface of the second intensity modulator, and the output end of the second intensity modulator and the input end of the photoelectric detector are respectively connected through optical fibers.

[0014] Optionally, the output end of the radio frequency signal generator is connected to the radio frequency input interface of the first intensity modulator via a radio frequency line;

[0015] The output end of the radio frequency signal generator is connected to the electric attenuator through a radio frequency line, and the electric attenuator is connected to the radio frequency input interface of the second intensity modulator through a radio frequency line.

[0016] The embodiment of the present invention further provides a method for generating a frequency-doubled triangle waveform, which is applied to the frequency-doubled triangle waveform generating system as described above, and the method comprises:

[0017] The first continuous light laser sends a first optical signal to the wavelength division multiplexer, the second continuous light laser sends a second optical signal to the first intensity modulator, and the radio frequency signal generator sends a first radio frequency sinusoidal signal to the first intensity modulator;

[0018] The first intensity modulator modulates the first radio frequency sinusoidal signal onto the second optical signal to obtain a third optical signal and positive and negative second-order sidebands deviating from the optical carrier, and sends the third optical signal and the positive and negative second-order sidebands deviating from the optical carrier to the wavelength division multiplexer;

[0019] The wavelength division multiplexer sends the first optical signal, the third optical signal and the positive and negative second-order sidebands deviating from the optical carrier to the second intensity modulator, and the radio frequency signal generator sends a second radio frequency sinusoidal signal to the second intensity modulator through the electrical attenuator;

[0020] The second intensity modulator modulates the second RF sinusoidal signal onto the first optical signal, the third optical signal and the positive and negative second-order sidebands deviating from the optical carrier to obtain the positive and negative first-order sidebands deviating from the optical carrier and the positive and negative third-order sidebands deviating from the optical carrier, and sends the positive and negative first-order sidebands deviating from the optical carrier and the positive and negative third-order sidebands deviating from the optical carrier to the photodetector;

[0021] The photodetector generates a frequency-doubled triangular wave signal according to the positive and negative first-order sidebands deviating from the optical carrier and the positive and negative third-order sidebands deviating from the optical carrier.

[0022] Optionally, the first optical signal and the second optical signal have different wavelengths.

[0023] Optionally, a wavelength interval between the first optical signal and the second optical signal is greater than or equal to 8 nm.

[0024] Optionally, the first optical signal and the second optical signal have the same optical power.

[0025] Optionally, the modulation depths of the first RF sinusoidal signal and the second RF sinusoidal signal are different;

[0026] The first RF sinusoidal signal and the second RF sinusoidal signal have the same frequency;

[0027] The first RF sinusoidal signal and the second RF sinusoidal signal have the same phase.

[0028] Optionally, the first intensity modulator modulates the first radio frequency sinusoidal signal onto the second optical signal to obtain positive and negative second-order sidebands deviating from the optical carrier, including:

[0029] The first intensity modulator operates at the highest bias point, modulates the first radio frequency sinusoidal signal onto the second optical signal, suppresses odd-order optical sidebands, and obtains the positive and negative second-order sidebands that deviate from the optical carrier.

[0030] Optionally, the second intensity modulator modulates the second radio frequency sinusoidal signal onto the first optical signal, the third optical signal, and the positive and negative second-order sidebands deviating from the optical carrier to obtain positive and negative first-order sidebands deviating from the optical carrier and positive and negative third-order sidebands deviating from the optical carrier, including:

[0031] The second intensity modulator operates at a minimum bias point, modulates the second radio frequency sinusoidal signal onto the first optical signal, suppresses the first optical signal, and obtains the positive and negative first-order sidebands deviating from the optical carrier;

[0032] The second intensity modulator modulates the second RF sinusoidal signal onto the third optical signal and the positive and negative second-order sidebands of the deviated optical carrier, suppresses the positive and negative second-order sidebands of the third optical signal and the deviated optical carrier, and obtains the positive and negative third-order sidebands of the deviated optical carrier.

[0033] Optionally, the photodetector generates a frequency-doubled triangular wave signal according to the positive and negative first-order sidebands deviating from the optical carrier and the positive and negative third-order sidebands deviating from the optical carrier, comprising:

[0034] The photodetector generates a double cosine signal, a sextuple cosine signal and a clutter signal according to the positive and negative first-order sidebands of the deviated optical carrier and the positive and negative third-order sidebands of the deviated optical carrier;

[0035] The photodetector generates a frequency-doubled triangle wave signal according to the twice cosine signal, the six times cosine signal and the clutter signal.

[0036] Beneficial effects of the present invention:

[0037] The frequency-doubled triangular waveform generation system provided by the scheme of the present invention comprises using two continuous light lasers (a first continuous light laser and a second continuous light laser), a first intensity modulator and a radio frequency signal generator to generate two optical carriers of different wavelengths as two channels, and synthesizing a triangular waveform with a repetition frequency twice that of the radio frequency signal by using a wavelength division multiplexer, a radio frequency signal generator, a second intensity modulator and a photodetector using wavelength multiplexing technology. Compared with the existing method of using a mode-locked laser to generate a wide-spectrum light source and a continuous light source to generate a microwave signal, the present invention uses a continuous laser light source instead of an expensive mode-locked laser device, which has low cost, simple structure, and easy operation, and compared with an external modulation system using a continuous light source as a carrier, the present invention is easy to generate a frequency-doubled signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 A schematic diagram of the structure of a frequency-doubled triangle waveform generation system provided by an embodiment of the present invention;

[0039] Figure 2 A flow chart of a method for generating a frequency-doubled triangle waveform provided by an embodiment of the present invention;

[0040] Figure 3 A time domain waveform diagram of a frequency-doubled triangle waveform provided by an embodiment of the present invention;

[0041] Figure 4 This is a power spectrum diagram of the frequency-doubled triangle waveform provided in an embodiment of the present invention.

[0042] Description of reference numerals:

[0043] 1-first continuous light laser; 2-second continuous light laser; 3-first intensity modulator; 4-wavelength division multiplexer; 5-second intensity modulator; 6-RF signal generator; 7-electric attenuator; 8-photoelectric detector. DETAILED DESCRIPTION

[0044] In order to make the technical problems, technical solutions and advantages to be solved by the present invention more clear, a detailed description will be given below with reference to the accompanying drawings and specific embodiments.

[0045] In order to solve the problem in the prior art that a frequency-doubled triangle waveform signal is difficult to generate, an embodiment of the present invention provides a frequency-doubled triangle waveform generation system and method.

[0046] like Figure 1 As shown, an embodiment of the present invention provides a frequency-doubled triangle waveform generation system, comprising:

[0047] A first continuous light laser 1, a second continuous light laser 2, a first intensity modulator 3, a wavelength division multiplexer 4, a second intensity modulator 5, a radio frequency signal generator 6, an electric attenuator 7, and a photodetector 8;

[0048] Among them, the output end of the first continuous light laser 1 is connected to the first input end of the wavelength division multiplexer 4; the output end of the second continuous light laser 2 is connected to the optical input interface of the first intensity modulator 3, and the output end of the first intensity modulator 3 is connected to the second input end of the wavelength division multiplexer 4; the output end of the wavelength division multiplexer 4 is connected to the optical input interface of the second intensity modulator 5, and the output end of the second intensity modulator 5 is connected to the input end of the photodetector 8; the output end of the radio frequency signal generator 6 is connected to the radio frequency input interface of the first intensity modulator 3, and the output end of the radio frequency signal generator 6 is connected to the radio frequency input interface of the second intensity modulator 5 through the electric attenuator 7.

[0049] The wavelengths of the optical signals (optical carriers) output by the two continuous light lasers (i.e., the first continuous light laser 1 and the second continuous light laser 2) are different, and the wavelength interval of the optical signals of the two continuous light lasers is greater than or equal to 8nm, and the optical powers are the same.

[0050] like Figure 1As described above, two continuous light lasers (ie, the first continuous light laser 1 and the second continuous light laser 2) are connected in parallel.

[0051] Optionally, the output end of the first continuous light laser 1 is connected to the first input end of the wavelength division multiplexer 4 through an optical fiber; the output end of the second continuous light laser 2 is connected to the optical input interface of the first intensity modulator 3, and the output end of the first intensity modulator 3 is connected to the second input end of the wavelength division multiplexer 4 through optical fibers; the output end of the wavelength division multiplexer 4 is connected to the optical input interface of the second intensity modulator 5, and the output end of the second intensity modulator 5 is connected to the input end of the photodetector 8 through optical fibers. That is, Figure 1 As shown, the first continuous light laser 1 and the wavelength division multiplexer 4, the second continuous light laser 2 and the first intensity modulator 3, the first intensity modulator 3 and the wavelength division multiplexer 4, the wavelength division multiplexer 4 and the second intensity modulator 5, and the second intensity modulator 5 and the photodetector 8 are connected through optical paths.

[0052] Optionally, the output end of the RF signal generator 6 is connected to the RF input interface of the first intensity modulator 3 via a RF line; the output end of the RF signal generator 6 is connected to the electric attenuator 7 via a RF line, and the electric attenuator 7 is connected to the RF input interface of the second intensity modulator 5 via a RF line. Figure 1 As shown, the RF signal generator 6 and the first intensity modulator 3 , the RF signal generator 6 and the electric attenuator 7 , and the electric attenuator 7 and the second intensity modulator 5 are connected via circuits.

[0053] like Figure 2 As shown, an embodiment of the present invention further provides a method for generating a frequency-doubled triangle waveform, which is applied to the frequency-doubled triangle waveform generating system as described above, and the method comprises:

[0054] Step 201: the first continuous light laser sends a first optical signal to the wavelength division multiplexer, the second continuous light laser sends a second optical signal to the first intensity modulator, and the radio frequency signal generator sends a first radio frequency sinusoidal signal to the first intensity modulator.

[0055] The first continuous light laser and the second continuous light laser are connected in parallel, the wavelength of the first light signal generated by the first continuous light laser is λ1, and the wavelength of the second light signal generated by the second continuous light laser is λ2. From the wavelength-frequency conversion formula ω=2πc / λ, it can be seen that the angular frequency of the optical carrier with a wavelength of λ1 is ω1, and the angular frequency of the optical carrier with a wavelength of λ2 is ω2.

[0056] The first optical signal output by the first continuous light laser is used as the upper branch carrier, and its time domain expression is recorded as: E in_1=E1exp(jω1t), the second optical signal output by the second continuous light laser is used as the lower branch carrier, and its time domain expression is recorded as: E in_2 =E2 exp(jω2t).

[0057] The first RF sinusoidal signal (RF drive signal) input by the RF signal generator to the first intensity modulator is: x1(t)=V RF1 sin(ωt), where V RF1 Represents the amplitude of the first RF sinusoidal signal.

[0058] The first optical signal and the second optical signal have different wavelengths.

[0059] The wavelength interval between the first optical signal and the second optical signal is greater than or equal to 8 nm, that is, the first continuous light laser and the second continuous light laser are used to generate continuous light with a wavelength interval greater than or equal to 8 nm as an optical carrier.

[0060] The first optical signal and the second optical signal have the same optical power.

[0061] Step 202: The first intensity modulator modulates the first RF sinusoidal signal onto the second optical signal to obtain a third optical signal and positive and negative second-order sidebands deviating from the optical carrier, and sends the third optical signal and the positive and negative second-order sidebands deviating from the optical carrier to the wavelength division multiplexer.

[0062] In this step, the second optical signal output by the second continuous light laser enters the first intensity modulator and is modulated with the first radio frequency sinusoidal signal.

[0063] The first optical signal output by the first continuous optical laser, the third optical signal output by the first intensity modulator, and the positive and negative second-order sidebands deviating from the optical carrier enter the wavelength division multiplexer.

[0064] Step 203: the wavelength division multiplexer sends the first optical signal, the third optical signal and the positive and negative second-order sidebands deviating from the optical carrier to the second intensity modulator, and the RF signal generator sends a second RF sinusoidal signal to the second intensity modulator through the electrical attenuator.

[0065] In this step, the wavelength division multiplexer is used to multiplex the optical signals in two parallel optical paths into the same optical path.

[0066] The electric attenuator is used for attenuating the power of the second radio frequency sinusoidal signal input to the second intensity modulator.

[0067] Step 204: The second intensity modulator modulates the second RF sinusoidal signal onto the first optical signal, the third optical signal and the positive and negative second-order sidebands that deviate from the optical carrier to obtain the positive and negative first-order sidebands that deviate from the optical carrier and the positive and negative third-order sidebands that deviate from the optical carrier, and sends the positive and negative first-order sidebands that deviate from the optical carrier and the positive and negative third-order sidebands that deviate from the optical carrier to the photodetector.

[0068] In this step, the optical signal output by the wavelength division multiplexer enters the second intensity modulator and is modulated with the second radio frequency sinusoidal signal to generate positive and negative first-order sidebands deviating from the optical carrier and positive and negative third-order sidebands deviating from the optical carrier.

[0069] Step 205: The photodetector generates a frequency-doubled triangular wave signal according to the positive and negative first-order sidebands deviating from the optical carrier and the positive and negative third-order sidebands deviating from the optical carrier.

[0070] In this step, the optical signal output by the second intensity modulator is converted by a photoelectric detector to obtain a frequency-doubled triangle wave signal. Specifically, the photoelectric detector is used to convert the multiplexed optical signal into an electrical signal, and at the same time, it acts as a low-pass filter to filter out ultra-high frequency electrical harmonics to obtain the expected frequency-doubled triangle wave signal.

[0071] Optionally, the modulation depths of the first RF sinusoidal signal and the second RF sinusoidal signal are different;

[0072] The first RF sinusoidal signal and the second RF sinusoidal signal have the same frequency;

[0073] The first RF sinusoidal signal and the second RF sinusoidal signal have the same phase.

[0074] In an optional embodiment, step 202 includes:

[0075] The first intensity modulator operates at the highest bias point, modulates the first radio frequency sinusoidal signal onto the second optical signal, suppresses odd-order optical sidebands, and obtains the positive and negative second-order sidebands deviating from the optical carrier, that is, the second optical signal output by the second continuous light laser enters the first intensity modulator and is modulated onto a sinusoidal signal, and the DC bias operates at the highest bias point, so that the odd-order optical sidebands are suppressed, and the positive and negative second-order sidebands deviating from the optical carrier are generated.

[0076] Specifically, the optical signal output by the first intensity modulator can be expressed as:

[0077]

[0078] Where m1 = πV RF1 / V π is the modulation coefficient of the first intensity modulator. is the phase introduced by the DC bias, V πis the half-wave voltage of the first intensity modulator, V1 is the DC bias voltage of the first intensity modulator, V RF1 is the amplitude of the RF signal input to the first intensity modulator.

[0079] Since the DC bias of the first intensity modulator works at the highest point, the output optical signal is expressed as:

[0080]

[0081] In an optional embodiment, step 204 includes:

[0082] The second intensity modulator operates at the lowest bias point, modulates the second radio frequency sinusoidal signal onto the first optical signal, suppresses the first optical signal, and obtains the positive and negative first-order sidebands deviating from the optical carrier, that is, the optical signal output by the wavelength division multiplexer enters the second intensity modulator and is modulated with the second radio frequency sinusoidal signal, the DC bias operates at the lowest bias point, the optical carrier generated by the first continuous optical laser is suppressed, and the positive and negative first-order sidebands deviating from the optical carrier are generated, and the second intensity modulator modulates the second radio frequency sinusoidal signal onto the third optical signal and the positive and negative second-order sidebands deviating from the optical carrier, suppresses the third optical signal and the positive and negative second-order sidebands deviating from the optical carrier, and obtains the positive and negative third-order sidebands deviating from the optical carrier, that is, the optical carrier output by the first intensity modulator and the positive and negative second-order sidebands are suppressed, and the positive and negative third-order sidebands deviating from the optical carrier are generated.

[0083] Specifically, the optical signal that is wavelength-division multiplexed to the same optical path is recorded as:

[0084]

[0085] The optical signal multiplexed by the wavelength division multiplexer enters the second intensity modulator for modulation. The second RF sinusoidal signal input to the second intensity modulator by the RF signal generator through the electrical attenuator is: x2(t)=V RF2 sin(ωt), where V RF2 is the amplitude of the second RF sinusoidal signal, and the DC bias of the second intensity modulator works at the lowest point. The signal E output by the second intensity modulator is out2 (t) (including positive and negative first-order sidebands and positive and negative third-order sidebands that deviate from the optical carrier) is recorded as:

[0086]

[0087] Where m2 = πV RF2 / V π is the modulation coefficient of the second intensity modulator, V RF2 is the amplitude of the RF signal input to the second intensity modulator, V π is the half-wave voltage of the second intensity modulator, EMUX is the signal output by the wavelength division multiplexer. According to the properties of the Bessel function:

[0088]

[0089] Where m = πV RF / V π is the modulation index of the modulator, V π is the half-wave voltage of the second intensity modulator, J n (·) is the first kind nth order Bessel function, J 2n (·) is an even-order Bessel function, and φ is the phase shift introduced by the DC bias.

[0090] By controlling the amplitudes of the first RF sinusoidal signal input to the first intensity modulator and the second RF sinusoidal signal input to the second intensity modulator to satisfy J0(m1)-J2(m1)=0, the optical signal output by the second intensity modulator can be rewritten as:

[0091]

[0092] In an optional embodiment, step 205 includes:

[0093] The photodetector generates a twice sine signal, a six times sine signal and a clutter signal according to the positive and negative first-order sidebands deviating from the optical carrier and the positive and negative third-order sidebands deviating from the optical carrier, that is, the optical signal output by the second intensity modulator is photoelectrically converted by the photodetector to generate a twice cosine signal, a six times cosine signal and other clutter signals, wherein the clutter signal includes an ultra-high frequency (terahertz level) electrical signal; the photodetector generates a doubled frequency triangular wave signal according to the twice sine signal, the six times sine signal and the clutter signal, specifically, after low-pass filtering with matching bandwidth of the photodetector (the bandwidth of the photodetector is limited), the ultra-high frequency electrical harmonics are filtered out, the amplitude ratio of the harmonics of the twice cosine signal and the six times cosine signal (radio frequency signal) frequency is 9:1, and the frequency-doubled triangular microwave signal can be successfully synthesized.

[0094] The optical signal output by the second intensity modulator is passed into the photodetector. Since the bandwidth of the photodetector is limited, the photodetector can be equivalent to a low-pass filter. As long as the interval between the two optical carriers of different frequencies is large enough (the spectral width of 0.8nm is equivalent to the bandwidth interval of 100GHz), the ultra-high frequency (terahertz level) electrical signal generated by the mutual beat frequency of the two wavelengths and sidebands will be filtered out. Therefore, the analog signal after photodetection is expressed as:

[0095]

[0096] The Fourier series expansion of an ideal symmetrical triangle wave is:

[0097]

[0098] Where n is an integer and C is a constant.

[0099] When only the first two harmonics of the ideal symmetrical triangular waveform are considered, the above equation must satisfy:

[0100]

[0101] Because the output powers of the first continuous light laser and the second continuous light laser are the same, it is necessary to satisfy Finally, the electrical signal output by the photodetector is the expected frequency-doubled triangle waveform signal.

[0102] By adopting this scheme, a triangular waveform with a frequency of 2ω can be obtained by inputting a radio frequency cosine signal with a frequency of ω. The radio frequency cosine ω in this embodiment is set to 5 GHz. The repetition frequency of the generated triangular microwave signal is 10 GHz. Figure 3 The time domain waveform diagram of the double frequency triangle waveform and Figure 4 Of course, the frequency of the RF signal can be selected according to actual needs, and the bandwidth of the photodetector can also be selected according to needs, but it must be ensured that the effective harmonics of the output electrical signal are within the bandwidth of the photodetector.

[0103] The present invention provides a wavelength multiplexing-assisted frequency-doubled triangular waveform generation system and method, which adopts dual-wavelength multiplexing as a dual-channel method to avoid the use of polarization modulators and polarization elements, thereby increasing the stability of the system; does not use an electrical phase shifter, is a method for all-optical synthesis of triangular microwave signals, is not limited by the bandwidth limitation of the electrical phase shifter, and has high tunability of the frequency of the generated waveform; does not use an integrated modulator, and simply uses two wavelengths, two intensity modulators, a wavelength division multiplexer, and a photoelectric detector to synthesize the frequency-doubled triangular waveform, which has low cost, simple structure, and is easy to implement.

[0104] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary personnel in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A frequency-doubled triangle waveform generation system, characterized in that: include: A first continuous light laser (1), a second continuous light laser (2), a first intensity modulator (3), a wavelength division multiplexer (4), a second intensity modulator (5), a radio frequency signal generator (6), an electric attenuator (7), and a photodetector (8); The output end of the first continuous light laser (1) is connected to the first input end of the wavelength division multiplexer (4); the output end of the second continuous light laser (2) is connected to the optical input interface of the first intensity modulator (3), and the output end of the first intensity modulator (3) is connected to the second input end of the wavelength division multiplexer (4); the output end of the wavelength division multiplexer (4) is connected to the optical input interface of the second intensity modulator (5), and the output end of the second intensity modulator (5) is connected to the input end of the photodetector (8); the output end of the radio frequency signal generator (6) is connected to the radio frequency input interface of the first intensity modulator (3), and the output end of the radio frequency signal generator (6) is connected to the radio frequency input interface of the second intensity modulator (5) through the electric attenuator (7).

2. The frequency-doubled triangle waveform generation system according to claim 1, wherein: The output end of the first continuous light laser (1) is connected to the first input end of the wavelength division multiplexer (4) via an optical fiber; The output end of the second continuous light laser (2) and the optical input interface of the first intensity modulator (3), and the output end of the first intensity modulator (3) and the second input end of the wavelength division multiplexer (4) are respectively connected via optical fibers; The output end of the wavelength division multiplexer (4) and the optical input interface of the second intensity modulator (5), as well as the output end of the second intensity modulator (5) and the input end of the photoelectric detector (8) are respectively connected via optical fibers.

3. The frequency-doubled triangle waveform generation system according to claim 1, wherein: The output end of the radio frequency signal generator (6) is connected to the radio frequency input interface of the first intensity modulator (3) via a radio frequency line; The output end of the radio frequency signal generator (6) is connected to the electric attenuator (7) via a radio frequency line, and the electric attenuator (7) is connected to the radio frequency input interface of the second intensity modulator (5) via a radio frequency line.

4. A method for generating a frequency-doubled triangle waveform, characterized in that: Applied to the frequency-doubled triangular waveform generation system according to any one of claims 1 to 3, the method comprising: The first continuous light laser sends a first optical signal to the wavelength division multiplexer, the second continuous light laser sends a second optical signal to the first intensity modulator, and the radio frequency signal generator sends a first radio frequency sinusoidal signal to the first intensity modulator; The first intensity modulator modulates the first radio frequency sinusoidal signal onto the second optical signal to obtain a third optical signal and positive and negative second-order sidebands deviating from the optical carrier, and sends the third optical signal and the positive and negative second-order sidebands deviating from the optical carrier to the wavelength division multiplexer; The wavelength division multiplexer sends the first optical signal, the third optical signal and the positive and negative second-order sidebands deviated from the optical carrier to the second intensity modulator, and the radio frequency signal generator sends a second radio frequency sinusoidal signal to the second intensity modulator through the electrical attenuator; The second intensity modulator modulates the second radio frequency sinusoidal signal onto the first optical signal, the third optical signal, and the positive and negative second-order sidebands deviating from the optical carrier to obtain positive and negative first-order sidebands deviating from the optical carrier and positive and negative third-order sidebands deviating from the optical carrier, and sends the positive and negative first-order sidebands deviating from the optical carrier and the positive and negative third-order sidebands deviating from the optical carrier to the photodetector; The photodetector generates a frequency-doubled triangular wave signal according to the positive and negative first-order sidebands deviating from the optical carrier and the positive and negative third-order sidebands deviating from the optical carrier.

5. The method for generating a frequency-doubled triangle waveform according to claim 4, wherein: The first optical signal and the second optical signal have different wavelengths.

6. The method for generating a frequency-doubled triangle waveform according to claim 4, wherein: A wavelength interval between the first optical signal and the second optical signal is greater than or equal to 8 nm.

7. The method for generating a frequency-doubled triangle waveform according to claim 4, wherein: The first optical signal and the second optical signal have the same optical power.

8. The method for generating a frequency-doubled triangle waveform according to claim 4, wherein: The first RF sinusoidal signal and the second RF sinusoidal signal have different modulation depths; The first radio frequency sinusoidal signal and the second radio frequency sinusoidal signal have the same frequency; The first radio frequency sinusoidal signal and the second radio frequency sinusoidal signal have the same phase.

9. The method for generating a frequency-doubled triangle waveform according to claim 4, wherein: The first intensity modulator modulates the first radio frequency sinusoidal signal onto the second optical signal to obtain positive and negative second-order sidebands deviating from the optical carrier, including: The first intensity modulator operates at the highest bias point, modulates the first RF sinusoidal signal onto the second optical signal, suppresses odd-order optical sidebands, and obtains the positive and negative second-order sidebands deviating from the optical carrier.

10. The method for generating a frequency-doubled triangle waveform according to claim 4, wherein: The second intensity modulator modulates the second RF sinusoidal signal onto the first optical signal, the third optical signal, and the positive and negative second-order sidebands deviating from the optical carrier to obtain positive and negative first-order sidebands deviating from the optical carrier and positive and negative third-order sidebands deviating from the optical carrier, including: The second intensity modulator operates at a minimum bias point, modulates the second radio frequency sinusoidal signal onto the first optical signal, suppresses the first optical signal, and obtains the positive and negative first-order sidebands deviating from the optical carrier; The second intensity modulator modulates the second RF sinusoidal signal onto the third optical signal and the positive and negative second-order sidebands of the deviated optical carrier, suppresses the positive and negative second-order sidebands of the third optical signal and the deviated optical carrier, and obtains the positive and negative third-order sidebands of the deviated optical carrier.

11. The method for generating a frequency-doubled triangle waveform according to claim 4, wherein: The photoelectric detector generates a frequency-doubled triangular wave signal according to the positive and negative first-order sidebands and the positive and negative third-order sidebands of the optical carrier, including: The photodetector generates a double cosine signal, a sextuple cosine signal and a clutter signal according to the positive and negative first-order sidebands and the positive and negative third-order sidebands of the deviated optical carrier; The photodetector generates a frequency-doubled triangle wave signal according to the twice cosine signal, the six times cosine signal, and the clutter signal.

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