Miniaturized microwave signal phase noise measurement system

Abstract

The present disclosure provides a miniaturized microwave signal phase noise measurement system, comprising: a laser for generating an optical carrier signal output to an on-chip cyclic phase modulator; the on-chip cyclic phase modulator is used for cyclically modulating a microwave signal to be measured on the optical carrier and output to an adjustable optical filter; a delay modulation device is used for modulating the first modulated optical carrier signal output by the on-chip cyclic phase modulator and output to the on-chip cyclic phase modulator; the adjustable optical filter extracts the second modulated optical carrier signal output by the on-chip cyclic phase modulator and outputs to a signal processing module; the signal processing module is used for processing the optical signal to be processed output by the adjustable optical filter to obtain the phase noise of the microwave signal to be measured. The miniaturized microwave signal phase noise measurement system of the present disclosure has a simple structure and is easy to integrate, and is not limited by the working bandwidth of any electrical device.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the field of microwave signal phase noise measurement and microwave photonics, and particularly relates to a miniaturized microwave signal phase noise measurement system. BACKGROUND

[0002] The most commonly used phase noise measurement methods at present mainly include direct spectrum technology and frequency discrimination technology; according to whether a reference source is needed, the frequency discrimination technology is divided into heterodyne frequency discrimination technology and autodyne frequency discrimination technology.

[0003] The direct spectrum technology calculates the phase noise of the measured microwave source by directly performing spectrum analysis on the input microwave signal, and the working bandwidth and the minimum noise floor of the system are limited by the performance of the spectrum analyzer, and the phase noise and amplitude noise of the measured source cannot be distinguished. The heterodyne frequency discrimination technology uses a reference source to mix with the measured source, and the bandwidth and phase noise floor of the system are limited by the bandwidth and phase noise of the reference source. The autodyne delay frequency discrimination method uses an electric phase shifter and an electric mixer, and it is difficult to meet the demand of low phase noise measurement in a bandwidth of 12G or more.

[0004] The phase noise measurement system based on the cascaded electro-optic modulation unit structure avoids the use of the electric mixer, but still uses the electric phase shifter and the electric coupler, and cannot avoid the bandwidth limitation caused by the electric devices.

[0005] In view of the above problems, the present disclosure provides a miniaturized microwave signal phase noise measurement system based on microwave photonics and on-chip cyclic phase modulator, which has the characteristics of simple system structure, high measurement bandwidth, easy integration and miniaturized packaging. SUMMARY

[0006] (I) Technical problems to be solved

[0007] Therefore, the present disclosure provides a miniaturized microwave signal phase noise measurement system, which uses an on-chip cyclic phase modulator to load the measured microwave signal into an optical carrier signal twice, and at least partially solves the above and other technical problems.

[0008] (II) Technical solutions

[0009] In order to achieve the above-mentioned purpose, the present disclosure provides a miniaturized microwave signal phase noise measurement system, comprising: a laser for generating an optical carrier signal, output to an on-chip cyclic phase modulator; the on-chip cyclic phase modulator is used for modulating the optical carrier signal generated by the laser twice with the microwave signal to be measured, and output to a tunable optical filter; a delay modulation device is used for modulating the first modulated optical carrier signal output by the on-chip cyclic phase modulator, and output to the on-chip cyclic phase modulator; the tunable optical filter is used for extracting the second modulated optical carrier signal output by the on-chip cyclic phase modulator, and output to a signal processing module; the signal processing module is used for processing the extracted optical carrier signal output by the tunable optical filter, to obtain the phase noise of the microwave signal to be measured.

[0010] According to the embodiments of the present disclosure, the laser is a continuous light output low phase noise semiconductor laser; the optical carrier signal wavelength is 1260-1360nm or 1530-1565nm.

[0011] According to the embodiments of the present disclosure, the on-chip cyclic phase modulator at least contains a first electro-optic modulation unit, a second electro-optic modulation unit, a first input port, a second input port, a first output port, a second output port; wherein the first input port is connected to the input port of the first electro-optic modulation unit; the output port of the first electro-optic modulation unit is connected to the first output port; the second input port is connected to the input port of the second electro-optic modulation unit; the output port of the second electro-optic modulation unit is connected to the second output port; the electro-optic modulation unit is used for modulating the microwave signal to be measured to the optical carrier signal; the first input port is used for receiving the optical carrier signal generated by the laser; the first output port is used for outputting the first modulated optical carrier signal; the second input port is used for receiving the first modulated optical carrier signal modulated in phase by the delay modulation device; the second output port is used for outputting the second modulated optical carrier signal.

[0012] According to the embodiments of the present disclosure, the on-chip cyclic phase modulator at least contains an electro-optic modulation unit, a mode multiplexing unit, a first input port, a second input port, a first output port, a second output port; wherein the first input port and the second input port are connected to the input end of the mode multiplexing unit; the output end of the mode multiplexing unit is connected to the first output port and the second output port; the electro-optic modulation unit is used for modulating the microwave signal to be measured to the optical carrier signal; the mode multiplexing unit is used for separating the first modulated optical carrier signal and the second modulated optical carrier signal in the on-chip cyclic phase modulator; the first input port is used for receiving the optical carrier signal generated by the laser; the first output port is used for outputting the first modulated optical carrier signal; the second input port is used for receiving the first modulated optical carrier signal modulated in phase by the delay modulation device; the second output port is used for outputting the second modulated optical carrier signal.

[0013] According to an embodiment of the present disclosure, the input port and the output port of the on-chip cyclic phase modulator are coupled to a single-mode fiber through a lens fiber or a lens.

[0014] According to an embodiment of the present disclosure, the delay modulation device comprises an adjustable optical fiber delay line and a delay fiber, which are used for delaying and modulating the phase to make the first modulated optical carrier signal and the second modulated optical carrier signal phase quadrature.

[0015] According to an embodiment of the present disclosure, the adjustable delay range of the adjustable optical fiber delay line is greater than the minimum period of the microwave signal to be measured.

[0016] According to an embodiment of the present disclosure, the delay fiber is a fixed delay fiber; the length of the delay fiber satisfies wherein L represents the length of the delay fiber, c represents the speed of light, n represents the refractive index of the delay fiber, and p represents the maximum frequency offset of the phase noise of the microwave signal to be measured.

[0017] According to an embodiment of the present disclosure, the adjustable optical filter is used for extracting the positive first-order sideband of the second modulated optical carrier signal to obtain a processed optical signal.

[0018] According to an embodiment of the present disclosure, the signal processing module further comprises a photoelectric detection unit, a data processing device, and a data acquisition card; the photoelectric detection unit is used for converting the selected optical carrier signal output by the adjustable optical filter into an electrical signal; and the data acquisition card is used for converting the electrical signal into a digital signal.

[0019] (III) Beneficial Effects

[0020] The present disclosure simplifies the structure of the microwave signal phase noise measurement system to be measured by using the on-chip cyclic phase modulator, and the measurement system is simple in structure and easy to integrate and miniaturize. Meanwhile, the on-chip cyclic phase modulator replaces the functions of the electrical phase shifter and the electrical coupler, the measurement system is not limited by the working bandwidth of any electrical device, but is determined by the working bandwidth of the on-chip cyclic phase modulator, and the measurement bandwidth of the measurement system is high. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 A schematic diagram of a miniaturized microwave signal phase noise measurement system according to an embodiment of the present disclosure is shown;

[0022] Figure 2 A schematic diagram of an on-chip cyclic phase modulator according to an embodiment of the present disclosure is shown;

[0023] Figure 3 A schematic diagram of an on-chip cyclic phase modulator according to another embodiment of the present disclosure is shown;

[0024] REFERENCE SIGNS:

[0025] 1-laser; 2-microwave signal to be measured; 3-on-chip cyclic phase modulator; 4-delay modulation device; 5-tunable optical filter; 6-signal processing module; 7-tunable optical fiber delay line; 8-delay optical fiber; 9-optoelectronic detection unit; 10-data processing device; 11-first input port; 12-second input port; 13-first output port; 14-second output port. DETAILED DESCRIPTION

[0026] To make the objects, technical solutions and advantages of the present disclosure clearer, further detailed description will be made to the present disclosure with reference to specific embodiments and drawings. Obviously, the described embodiments are only part of the embodiments of the present disclosure, rather than all the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present disclosure.

[0027] Embodiments of the present disclosure provide a miniaturized microwave signal to be measured phase noise measurement system. The system comprises a laser, an on-chip cyclic phase modulator, a delay modulation device, a tunable optical filter, and a signal processing module. The miniaturized microwave signal to be measured phase noise measurement system provided in the embodiments of the present disclosure has at least the following beneficial effects:

[0028] (1) Low cost, simple system structure, easy to integrate and miniaturized packaging.

[0029] (2) Large test bandwidth, not limited by the working bandwidth of any electrical device, only determined by the working bandwidth of the on-chip cyclic phase modulator.

[0030] Figure 1 A schematic diagram of the miniaturized microwave signal to be measured phase noise measurement system in the embodiments of the present disclosure.

[0031] As shown in Figure 1 The present disclosure provides a miniaturized microwave signal to be measured phase noise measurement system, which comprises a laser 1 for generating an optical carrier signal and outputting to an on-chip cyclic phase modulator 3; the on-chip cyclic phase modulator 3 is used to modulate the optical carrier signal generated by the laser 1 twice with the microwave signal to be measured 2 and output to a tunable optical filter 5; a delay modulation device 4 is used to modulate the first modulated optical carrier signal output by the on-chip cyclic phase modulator 3 and output to the on-chip cyclic phase modulator 3; the tunable optical filter 5 is used to extract the second modulated optical carrier signal output by the on-chip cyclic phase modulator 3 and output to a signal processing module; the signal processing module 6 is used to process the extracted optical carrier signal output by the tunable optical filter 5 to obtain the phase noise of the microwave signal to be measured.

[0032] In this embodiment, the electrical input port of the on-chip circulatory phase modulator is coupled through a planar waveguide, and the 3dB bandwidth of the on-chip circulatory modulator is higher than the output frequency of the microwave signal to be measured.

[0033] Through the embodiment of the present disclosure, the miniaturized microwave signal phase noise measurement system based on microwave photonics and on-chip circulatory phase modulator, the on-chip circulatory phase modulator is recycled through the method of circulatory modulation and waveguide mode isolation, which effectively reduces the system cost, and the system operating bandwidth is not limited by the bandwidth limitation of the electrical device.

[0034] On the basis of the above embodiment, the laser 1 is a continuous light output low phase noise semiconductor laser; the optical carrier signal wavelength is 1260-1360nm or 1530-1565nm.

[0035] Through the embodiment of the present disclosure, the bandwidth of the microwave signal to be measured is expanded by the high frequency and high energy optical carrier signal, the characteristics of the microwave signal to be measured are transmitted, and the anti-interference ability of the system is improved.

[0036] On the basis of the above embodiment, the on-chip circulatory phase modulator at least includes a first electro-optical modulation unit, a second electro-optical modulation unit, a first input port, a second input port, a first output port, and a second output port; wherein the first input port is connected to the input port of the first electro-optical modulation unit; the output port of the first electro-optical modulation unit is connected to the first output port; the second input port is connected to the input port of the second electro-optical modulation unit; the output port of the second electro-optical modulation unit is connected to the second output port; the electro-optical modulation unit is used for modulating the microwave signal to be measured to the optical carrier signal; the first input port is used for receiving the optical carrier signal generated by the laser; the first output port is used for outputting the first modulated optical carrier signal; the second input port is used for receiving the first modulated optical carrier signal modulated in phase by the delay modulation device; and the second output port is used for outputting the second modulated optical carrier signal.

[0037] For example, Figure 2 A schematic diagram of the on-chip circulatory phase modulator in an embodiment of the present disclosure is shown. The continuous optical carrier signal output by the laser enters the on-chip circulatory phase modulator through the first input port 11, the first electro-optical modulation unit modulates the microwave signal to be measured to the optical carrier signal for the first time, and outputs the first modulated optical carrier signal to the delay modulation device through the first output port 13; the optical carrier signal modulated by the delay modulation device enters the on-chip circulatory phase modulator through the second input port 12, the second electro-optical modulation unit loads the microwave signal to be measured to the optical carrier signal, and obtains the second modulated optical carrier signal, which is output through the second output port 14.

[0038] Through the embodiment of the present disclosure, the on-chip cyclic phase modulator realizes twice modulation of the optical carrier signal, realizes separation of the optical carrier signal after the first modulation and the optical carrier signal after the second modulation, and thus simplifies the system structure while modulating the signal.

[0039] On the basis of the above embodiment, the on-chip cyclic phase modulator at least comprises an electro-optical modulation unit, a mode multiplexing unit, a first input port, a second input port, a first output port, and a second output port; wherein the first input port and the second input port are connected to the mode multiplexing unit input end; the mode multiplexing unit output end is connected to the first output port and the second output port; the electro-optical modulation unit is used for modulating the to-be-tested microwave signal to the optical carrier signal; the mode multiplexing unit is used for separating the optical carrier signal after the first modulation and the optical carrier signal after the second modulation in the on-chip cyclic phase modulator; the first input port is used for receiving the optical carrier signal generated by the laser; the first output port is used for outputting the optical carrier signal after the first modulation; and the second input port is used for receiving the optical carrier signal after the first modulation and the modulation phase after the delay modulation device; and the second output port is used for outputting the optical carrier signal after the second modulation.

[0040] For example, Figure 3 A schematic diagram of the on-chip cyclic phase modulator in another embodiment of the present disclosure is shown. The continuous optical carrier signal output by the laser enters the on-chip cyclic phase modulator through the first input port 11, the electro-optical modulation unit modulates the microwave signal of the to-be-tested microwave signal to the optical carrier signal for the first time, at this time the optical mode is the optical carrier signal of the fundamental transverse electric field mode, and is output to the delay modulation device through the first output port 13; the optical carrier signal after the delay modulation device is modulated enters the on-chip cyclic phase modulator through the second input port 12, the mode multiplexing unit changes the optical carrier signal to the optical carrier signal of the second-order transverse electric field mode, and again loads the microwave signal of the to-be-tested microwave signal to the optical carrier signal, obtains the optical carrier signal after the second modulation, and changes back to the optical carrier signal of the fundamental transverse electric field mode, and is output through the second output port 14; in this embodiment, the mode multiplexing unit is used for separating the optical carrier signal of the fundamental transverse electric field mode and the optical carrier signal of the second-order transverse electric field mode.

[0041] Through the embodiment of the present disclosure, the on-chip cyclic phase modulator adopts the mode multiplexing unit to realize the separation of the optical carrier signal without additional signal transmission optical path, and reduces the integration difficulty.

[0042] On the basis of the above embodiment, the input port and the output port of the on-chip cyclic phase modulator 3 are coupled to the single-mode optical fiber through the lens optical fiber or the lens.

[0043] Through the embodiment of the present disclosure, the coupling between the optical fiber and the waveguide device is improved through the lens optical fiber or the lens, and the system stability is improved.

[0044] On the basis of the above-mentioned embodiment, the time delay modulation device 4 comprises an adjustable optical fiber time delay line 7 and a time delay optical fiber 8, which are used for time delay and modulation phase to make the phase of the first modulated optical carrier signal and the second modulated optical carrier signal orthogonal.

[0045] Through the embodiment of the present disclosure, the first modulated optical carrier signal and the second modulated optical carrier signal are orthogonal, which is beneficial to the signal processing module to successfully recover the original signal.

[0046] On the basis of the above-mentioned embodiment, the adjustable time delay range of the adjustable optical fiber time delay line 7 is greater than the minimum period of the to-be-measured microwave signal.

[0047] Through the embodiment of the present disclosure, the adjustable time delay is provided by the adjustable optical fiber time delay line 7, and the phase of the twice phase-modulated signal is adjusted to be orthogonal.

[0048] On the basis of the above-mentioned embodiment, the time delay optical fiber 8 is a fixed time delay; the length of the time delay optical fiber satisfies Wherein, L represents the length of the time delay optical fiber, c represents the speed of light, n represents the refractive index of the time delay optical fiber, and p represents the maximum frequency offset of the microwave signal phase noise.

[0049] Through the embodiment of the present disclosure, the fixed time delay is provided by the time delay optical fiber, and the phase of the modulated optical carrier signal is adjusted.

[0050] On the basis of the above-mentioned embodiment, the adjustable optical filter 5 is used for extracting the positive first-order sideband of the second modulated optical carrier signal to obtain a to-be-processed optical signal.

[0051] In this embodiment, the center frequency adjustment range of the adjustable optical filter 5 is greater than the microwave signal frequency of the to-be-measured microwave signal 2, and the 3dB filtering bandwidth of the adjustable optical filter 5 is less than the microwave signal frequency of the to-be-measured microwave signal.

[0052] Through the embodiment of the present disclosure, the positive and negative first-order sidebands of the optical carrier signal contain the to-be-measured microwave signal phase noise information, so only the positive first-order sideband of the optical carrier signal needs to be selected for signal processing.

[0053] On the basis of the above-mentioned embodiment, the signal processing module 6 further comprises a photoelectric detection unit 9, a data processing device 10, and a data acquisition card; the photoelectric detection unit 9 is used for converting the selected optical carrier signal output by the adjustable optical filter into an electrical signal; and the data acquisition card is used for converting the electrical signal into a digital signal.

[0054] In this embodiment, the data acquisition card is installed on the data processing device 10; and the data processing device 10 obtains the phase noise of the to-be-measured microwave signal through digital filtering, amplification, fast Fourier transform, and transfer function calibration on the output digital signal of the data acquisition card.

[0055] In this embodiment, the analog bandwidth of the photodetection unit 9 is higher than the maximum frequency offset of the phase noise of the microwave signal to be measured.

[0056] Through the embodiments of the present disclosure, the signal processing module realizes the conversion of the optical signal to the electrical signal to the digital signal, facilitates data processing, and obtains the noise of the microwave signal to be measured through various data processing methods.

[0057] Embodiment one

[0058] The optical carrier signal output by the laser 1 is represented as:

[0059] E in (t)=E c exp(jω c t) (1)

[0060] In the formula, E c is the amplitude of the electric field of the optical signal, ω c is the angular frequency of the optical carrier, j is the imaginary unit, and t is the time.

[0061] The microwave signal output by the microwave signal to be measured 2 can be represented as:

[0062]

[0063] In the formula, E RF is the amplitude of the microwave signal, ω RF is the angular frequency of the microwave signal, is the phase noise of the microwave signal to be measured, and t is the time.

[0064] The optical carrier signal after the first modulation of the on-chip cyclic phase modulator 3 is represented as:

[0065]

[0066] In the formula, β0 is the modulation depth of the on-chip cyclic phase modulator 3, and the modulation depth β0 is determined by the amplitude of the microwave signal and the half-wave voltage of the on-chip cyclic phase modulator 3; written in the form of a virtual exponential signal, that is, an equal-amplitude sinusoidal signal.

[0067] The optical carrier signal after passing through the delay modulation device 4 is represented as:

[0068]

[0069] In the formula, τ is the total delay amount provided by the adjustable optical fiber delay line 7 and the delay optical fiber 8, and τ can be finely adjusted by the adjustable optical fiber delay line 7.

[0070] After the second modulation of the on-chip cyclic phase modulator 3, the expression of the output optical carrier signal is represented as:

[0071]

[0072] The optical carrier signal outputted by the on-chip cyclic phase modulator 3 is expressed by Bessel function expansion as follows:

[0073]

[0074] The above formula can be simplified as follows:

[0075]

[0076] After the adjustable optical filter 5, the negative first-order sideband and the central carrier generated by twice modulation are filtered out, and the positive first-order sideband is reserved. At this time, n=0, m=1 and n=1, m=0 of the above formula can be expressed as the output signal of the adjustable optical filter 5 as follows:

[0077]

[0078] The photoelectric detection unit 9 receives the optical signal filtered by the adjustable optical filter 5, and the output electrical signal is as follows:

[0079]

[0080] The output signal of the photoelectric detection unit 9 can be expressed as:

[0081]

[0082] The signal outputted by the photoelectric detection unit 9 is converted into a digital signal after low-pass filtering, amplification, high-pass filtering and amplification into a data acquisition card:

[0083]

[0084] The k factor in the above formula can be obtained by changing the delay amount of the adjustable optical fiber delay line 4 before measurement; the k factor is a calibrated parameter, and if this parameter is not obtained, the absolute value of the measured phase noise is not accurate.

[0085] The delay amount of the adjustable optical fiber delay line 4 is adjusted to make:

[0086]

[0087] The output signal is subjected to fast Fourier transform by the signal processing module 8 to obtain the power spectral density of the output signal:

[0088]

[0089] The phase noise of the measured microwave signal 2 to be solved is generally expressed as a single sideband phase noise power spectral density:

[0090]

[0091] The phase noise of the microwave signal 4 to be measured can be obtained from the calculated power spectral density:

[0092]

[0093] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used herein, the term "includes" and tautological expressions thereof, such as "including," "includes," "include," "contains," "containing," and so forth, mean that the disclosed feature, step, operation, and / or component is present, but not excluding the possible presence or addition of one or more other features, steps, operations, and / or components.

[0094] In the present disclosure, unless specifically defined otherwise, the terms "mounting", "connected", "connecting", "fixed", and "fixedly" should be understood broadly, for example, can be fixedly connected, or can be detachably connected, or can be integrated; can be mechanically connected, or can be electrically connected, or can be in communication with each other; can be directly connected, or can be indirectly connected through an intermediate medium; can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meanings of the above terms in the present disclosure can be understood according to the specific circumstances.

[0095] Similarly, in order to simplify the present disclosure and help understand one or more of the various disclosed aspects, in the above description of the exemplary embodiments of the present disclosure, various features of the present disclosure are sometimes grouped together in a single embodiment, figure, or description thereof. The description referring to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present disclosure. In the present description, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0096] The above specific embodiments further illustrate the purpose, technical solutions and beneficial effects of the present disclosure. It should be understood that the above are only specific embodiments of the present disclosure and are not intended to limit the present disclosure. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present disclosure shall be included in the protection scope of the present disclosure.

Claims

1. A miniaturized system for measuring phase noise of a microwave signal under test, characterized in that, The application relates to a microwave signal phase noise measurement device and method. The application comprises the following parts: a laser (1) for generating an optical carrier signal and outputting to an on-chip cyclic phase modulator (3); the on-chip cyclic phase modulator (3) is used for modulating the optical carrier signal generated by the laser (1) twice with a microwave signal to be measured (2) and outputting to an adjustable optical filter (5); a delay modulation device (4) is used for modulating the first modulated optical carrier signal output by the on-chip cyclic phase modulator (3) and outputting to the on-chip cyclic phase modulator (3); the adjustable optical filter (5) is used for extracting the second modulated optical carrier signal output by the on-chip cyclic phase modulator (3) and outputting to a signal processing module (8); the signal processing module (6) is used for processing the extracted optical carrier signal output by the adjustable optical filter (5) to obtain the phase noise of the microwave signal to be measured (2); the on-chip cyclic phase modulator (3) at least comprises a first electro-optic modulation unit, a second electro-optic modulation unit, a first input port (11), a second input port (12), a first output port (13) and a second output port (14); wherein the first input port is connected to the input port of the first electro-optic modulation unit; the output port of the first electro-optic modulation unit is connected to the first output port; the second input port is connected to the input port of the second electro-optic modulation unit; the output port of the second electro-optic modulation unit is connected to the second output port; the electro-optic modulation unit is used for modulating the microwave signal to be measured to the optical carrier signal; the first input port is used for receiving the optical carrier signal generated by the laser (1); the first output port is used for outputting the first modulated optical carrier signal; the second input port is used for receiving the first modulated optical carrier signal modulated in phase by the delay modulation device (4); and the second output port is used for outputting the second modulated optical carrier signal; or the on-chip cyclic phase modulator (3) at least comprises an electro-optic modulation unit, a mode multiplexing unit, a first input port (11), a second input port (12), a first output port (13) and a second output port (14); wherein the first input port and the second input port are connected to the input end of the mode multiplexing unit; the output end of the mode multiplexing unit is connected to the first output port and the second output port; the electro-optic modulation unit is used for modulating the microwave signal to be measured to the optical carrier signal; the mode multiplexing unit is used for separating the first modulated optical carrier signal and the second modulated optical carrier signal in the on-chip cyclic phase modulator (3); the first input port is used for receiving the optical carrier signal generated by the laser (1); the first output port is used for outputting the first modulated optical carrier signal; the second input port is used for receiving the first modulated optical carrier signal modulated in phase by the delay modulation device (4); and the second output port is used for outputting the second modulated optical carrier signal.

2. The miniaturized microwave signal under test phase noise measurement system of claim 1, wherein, The laser (1) is a low phase noise semiconductor laser with continuous light output; the optical carrier signal wavelength is between 1260-1360nm or 1530-1565nm.

3. The miniaturized microwave signal under test phase noise measurement system of claim 1, wherein, The input port and the output port of the on-chip cyclic phase modulator (3) are coupled to a single mode fiber through a lens fiber or a lens.

4. The miniaturized microwave signal under test phase noise measurement system of claim 1, wherein, The delay modulation device (4) comprises an adjustable optical fiber delay line (7) and a delay fiber (8) for delaying and modulating the phase so that the phase of the first modulated optical carrier signal and the second modulated optical carrier signal is orthogonal.

5. The miniaturized microwave signal under test phase noise measurement system of claim 4, wherein, The adjustable delay range of the adjustable optical fiber delay line (7) is greater than the minimum period of the microwave signal to be measured.

6. The miniaturized DUT microwave signal phase noise measurement system of claim 4, wherein, The length of the delay optical fiber (8) satisfies , Wherein, L represents the length of the delay fiber, c represents the speed of light, n represents the refractive index of the delay fiber, and p represents the maximum frequency offset of the phase noise of the microwave signal to be measured.

7. The miniaturized microwave signal phase noise under test measuring system according to claim 1, wherein, The adjustable optical filter (6) is used for extracting the positive first-order sideband of the second modulated optical carrier signal to obtain a to-be-processed optical signal.

8. The miniaturized microwave signal under test phase noise measurement system of claim 1, wherein, The signal processing module (6) further comprises a photoelectric detection unit (9), a data processing device (10), and a data acquisition card; the photoelectric detection unit (9) is used for converting the selected optical carrier signal output by the adjustable optical filter (5) into an electrical signal; and the data acquisition card is used for converting the electrical signal into a digital signal.

Images