Timing jitter measuring device and method for laser

Abstract

The invention discloses a timed jitter measuring device and method for a laser, and the device comprises a first light collimator which is used for converting a laser pulse signal outputted by a to-be-measured laser into spatial parallel light; the cascade space type Mach-Zehnder interference structure is used for multiplying to obtain a multi-stage multiplied laser pulse signal; the second light collimator is used for focusing to obtain a focused laser pulse signal; the photoelectric detector is used for converting to obtain a plurality of radio frequency signals; the radio frequency filter is used for filtering to obtain a filtered radio frequency signal; and the phase noise analyzer is used for carrying out phase noise analysis to obtain the timing jitter of the laser pulse signal. A laser pulse signal is subjected to spatial parallel light conversion, repetition frequency multiplication and focusing, and then timing jitter of the laser pulse signal is measured. By carrying out spatial parallel light conversion, repetition frequency multiplication and focusing pretreatment on the laser pulse signal, the measurement precision of the timing jitter of the laser pulse signal is improved.

Description

Technical Field

[0001] This invention relates to the field of ultrafast laser technology, and more particularly to a timing jitter measurement device and method for lasers. Background Technology

[0002] Since their inception, ultrafast lasers have been widely used in ultrafast optical imaging, high-speed optical sampling, and the processing of special materials due to their characteristics such as short pulse widths, wide coherence spectra, and high peak power. In addition, ultrafast lasers possess ultra-low timing jitter, laying the foundation for building low-noise optical frequency combs and greatly promoting the development of precision optical frequency measurement, precision spectral measurement, and high-precision absolute distance measurement. For these reasons, timing jitter is one of the important indicators for evaluating the performance of ultrafast lasers, and measuring its timing jitter can provide a basis for the design improvement and application of ultrafast lasers.

[0003] Common methods for measuring timing jitter in ultrafast lasers include: 1. Photodetector-based methods; 2. Balanced optical cross-correlation-based methods; and 3. Fiber optic delay line interferometry-based methods. In existing technologies, photodetector-based methods convert the laser pulse signal output by the ultrafast laser into an radio frequency signal, and then use a phase noise analyzer to detect the phase noise of the high-order harmonics of the ultrafast laser's repetition frequency, thereby determining the timing jitter. This method is simple in structure, technologically mature, and inexpensive. However, the photoelectric conversion process during measurement introduces excessively high phase noise, resulting in a higher measured timing jitter than the actual value.

[0004] Therefore, existing technologies still need improvement and development. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a timing jitter measurement device and method for lasers, which addresses the above-mentioned deficiencies of the prior art and aims to solve the problem of low measurement accuracy in the timing jitter measurement based on photodetectors in the prior art.

[0006] The technical solution adopted by this invention to solve the technical problem is as follows: A timing jitter measuring device for a laser, comprising: The first optical collimator is used to convert the laser pulse signal output by the laser under test into spatially parallel light; A cascaded spatial Mach-Zehnder interferometer structure is used to multiply the repetition frequency of the spatial parallel light to obtain a multiplied laser pulse signal. The second optical collimator is used to focus the multi-stage amplified laser pulse signal to obtain a focused laser pulse signal; A photodetector is used to convert a focused laser pulse signal into multiple radio frequency signals, including the fundamental frequency and higher harmonics. A radio frequency filter is used to filter out higher harmonics in the radio frequency signal to obtain the filtered radio frequency signal. A phase noise analyzer is used to perform phase noise analysis on the filtered radio frequency signal to obtain the timing jitter of the laser pulse signal.

[0007] The timing jitter measurement device for the laser, wherein the cascaded spatial Mach-Zehnder interferometer structure includes: A first-order spatial Mach-Zehnder interferometer structure is used to multiply the repetition frequency of the spatial parallel light to obtain a first-order multiplied laser pulse signal. The second-order spatial Mach-Zehnder interferometer structure is used to multiply the repetition frequency of the first-order multiplied laser pulse to obtain a second-order multiplied laser pulse signal. A third-order spatial Mach-Zehnder interferometer structure is used to multiply the repetition frequency of the second-order multiplied laser pulse to obtain a multi-order multiplied laser pulse signal.

[0008] The timing jitter measurement device for the laser, wherein the first-stage spatial Mach-Zehnder interferometer structure, the second-stage spatial Mach-Zehnder interferometer structure, and the third-stage spatial Mach-Zehnder interferometer structure each include: Half-wave plate, polarizing beam splitter, first quarter-wave plate, first mirror, second quarter-wave plate and second mirror; The half-wave plate is located on the first side of the polarizing beam splitter, the first quarter-wave plate is located on the second side of the polarizing beam splitter, the second quarter-wave plate is located on the third side of the polarizing beam splitter, and the first mirror is located on the side of the first quarter-wave plate away from the polarizing beam splitter, and the second mirror is located on the side of the second quarter-wave plate away from the polarizing beam splitter. The first side, the second side, and the third side are adjacent to each other.

[0009] The timing jitter measurement device for the laser, wherein the half-wave plate of the second-stage spatial Mach-Zehnder interferometer structure is located on the fourth side of the polarization beam splitter of the first-stage spatial Mach-Zehnder interferometer structure; The half-wave plate of the third-level spatial Mach-Zehnder interferometer structure is located on the fourth side of the polarization beam splitter of the second-level spatial Mach-Zehnder interferometer structure.

[0010] The timing jitter measurement device for the laser, wherein the length difference between the two arms of the first-stage spatial Mach-Zehnder interferometer structure is: L1 = c / (2×f1); Where L1 represents the difference in length between the two arms of the first-order spatial Mach-Zehnder interference structure, c represents the speed of light, and f1 represents the repetition frequency of the spatial parallel light. The difference in length between the two arms of the second-order spatial Mach-Zehnder interferometer structure is: L2 = c / (2×f2); f2 = 2 × f1; Where L2 represents the difference in length between the two arms of the second-order spatial Mach-Zehnder interference structure, and f2 represents the repetition frequency of the first-order multiplied laser pulse signal; The difference in length between the two arms of the third-order spatial Mach-Zehnder interferometer structure is: L3 = c / (2×f3); f3 = 2 × f2; Where L3 represents the difference in length between the two arms of the third-order spatial Mach-Zehnder interferometer structure, and f3 represents the repetition frequency of the second-order multiplied laser pulse signal; The repetition frequency of the multi-stage amplified laser pulse signal is: f4 = 2 × f3; Where f4 represents the repetition frequency of the multiplied laser pulse signal.

[0011] The timing jitter measurement device for the laser, wherein the fundamental frequency is f4; the frequency of the higher harmonics is n*f4, where n represents an integer; and the frequency of the filtered radio frequency signal is k*f4, where k represents an integer. <n。

[0012] A method for measuring timing jitter in a laser, wherein the timing jitter measurement method includes the following steps: Based on the first optical collimator, the laser pulse signal output by the laser under test is converted into spatially parallel light; Based on the cascaded spatial Mach-Zehnder interferometer structure, the repetition frequency of the spatial parallel light is multiplied to obtain a multi-level multiplied laser pulse signal; Based on the second optical collimator, the multi-stage amplified laser pulse signal is focused to obtain a focused laser pulse signal; Based on a photodetector, the focused laser pulse signal is converted into multiple radio frequency signals, including the fundamental frequency and higher harmonics; Based on the radio frequency filter, higher harmonics are filtered out from the radio frequency signal to obtain the filtered radio frequency signal; Based on a phase noise analyzer, the filtered radio frequency signal is subjected to phase noise analysis to obtain the timing jitter of the laser pulse signal.

[0013] The laser timing jitter measurement method, wherein the step of multiplying the repetition frequency of the spatially parallel light to obtain a multi-level multiplied laser pulse signal based on a cascaded spatial Mach-Zehnder interferometer structure includes: Based on the first-order spatial Mach-Zehnder interferometer structure, the repetition frequency of the spatial parallel light is multiplied to obtain a first-order multiplied laser pulse signal; Based on the second-order spatial Mach-Zehnder interferometer structure, the repetition frequency of the first-order multiplied laser pulse is multiplied to obtain a second-order multiplied laser pulse signal; Based on the third-order spatial Mach-Zehnder interferometer structure, the repetition frequency of the second-order multiplied laser pulse is multiplied to obtain a multi-order multiplied laser pulse signal.

[0014] Beneficial effects: The laser pulse signal output from the laser under test is first subjected to spatial parallelization, repetition frequency multiplication, and focusing. Then, photoelectric conversion, high-order harmonic filtering, and phase noise analysis are performed to finally obtain the timing jitter of the laser pulse signal. By performing preprocessing such as spatial parallelization, repetition frequency multiplication, and focusing on the laser pulse signal output from the laser under test, the measurement accuracy of the timing jitter of the laser pulse signal is improved. Attached Figure Description

[0015] Figure 1 This is a functional principle block diagram of the timing jitter measurement device for the laser in an embodiment of the present invention.

[0016] Figure 2 This is a functional principle block diagram of the cascaded spatial Mach-Zehnder interference structure in an embodiment of the present invention.

[0017] Figure 3 This is a comparison chart of the timing jitter results of the ultrafast laser measured according to the embodiments of the present invention and the timing jitter results of the ultrafast laser directly measured by the photodetector.

[0018] Figure 4 This is a flowchart of the timing jitter measurement method for a laser in an embodiment of the present invention.

[0019] Explanation of reference numerals in the attached figures: 1. The laser to be tested; 2. First optical collimator; 3. Cascaded spatial Mach-Zehnder interferometer structure; 31. First-order spatial Mach-Zehnder interferometer structure; 311. Half-wave plate; 312. Polarizing beam splitter; 313. First quarter-wave plate; 314. First mirror; 315. Second quarter-wave plate; 316. Second mirror; 32. Second-order spatial Mach-Zehnder interferometer structure; 321. Half-wave plate; 322. Polarizing beam splitter; 323. First quarter-wave plate; 324. First mirror; 325. Second quarter-wave plate; 326. Second mirror; 33. Third-order spatial Mach-Zehnder interferometer structure; 331. Half-wave plate; 332. Polarizing beam splitter; 333. First quarter-wave plate; 334. First mirror; 335. Second quarter-wave plate; 336. Second mirror; 4. Second optical collimator; 5. Photodetector; 6. Radio frequency filter; 7. Phase noise analyzer. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this invention clearer and more explicit, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0021] Please also refer to Figures 1-3 This invention provides some embodiments of a timing jitter measurement device for lasers.

[0022] like Figure 1 As shown, the timing jitter measuring device for a laser of the present invention includes: The first optical collimator 2 is used to convert the laser pulse signal output by the laser under test 1 into spatially parallel light; A cascaded spatial Mach-Zehnder interferometer structure 3 is used to multiply the repetition frequency of the spatial parallel light to obtain a multi-level multiplied laser pulse signal; The second optical collimator 4 is used to focus the multi-stage amplified laser pulse signal to obtain a focused laser pulse signal; Photodetector 5 is used to convert the focused laser pulse signal into multiple radio frequency signals, including the fundamental frequency and higher harmonics; RF filter 6 is used to filter out high-order harmonics in the RF signal to obtain the filtered RF signal; The phase noise analyzer 7 is used to perform phase noise analysis on the filtered radio frequency signal to obtain the timing jitter of the laser pulse signal.

[0023] Specifically, the laser under test 1 is an ultrafast laser, which refers to a laser whose output pulse width is 10. - 12 "s" refers to picosecond-level or smaller pulsed lasers. The timing jitter measurement device for lasers measures the timing jitter of the laser under test (laser 1). Instead of directly converting the laser pulse signal output by laser 1 into photoelectric signal, it first performs spatial parallelization, repetition frequency multiplication, and focusing on the laser pulse signal. Then, it performs photoelectric conversion, high-order harmonic filtering, and phase noise analysis to finally obtain the timing jitter of the laser pulse signal. This preprocessing—spatial parallelization, repetition frequency multiplication, and focusing—improves the measurement accuracy of the laser pulse signal's timing jitter.

[0024] In a preferred implementation of this invention, such as Figures 1-2 As shown, the cascaded spatial Mach-Zehnder interferometer structure 3 includes: The first-order spatial Mach-Zehnder interference structure 31 is used to multiply the repetition frequency of the spatial parallel light to obtain a first-order multiplied laser pulse signal; The second-order spatial Mach-Zehnder interferometer structure 32 is used to multiply the repetition frequency of the first-order multiplied laser pulse to obtain a second-order multiplied laser pulse signal. The third-order spatial Mach-Zehnder interferometer structure 33 is used to multiply the repetition frequency of the second-order multiplied laser pulse to obtain a multi-order multiplied laser pulse signal.

[0025] Specifically, the cascaded spatial Mach-Zehnder interferometer structure 3 is a structure formed by cascading multiple spatial Mach-Zehnder interferometer structures. There can be three spatial Mach-Zehnder interferometer structures: a first-stage spatial Mach-Zehnder interferometer structure 31, a second-stage spatial Mach-Zehnder interferometer structure 32, and a third-stage spatial Mach-Zehnder interferometer structure 33. The repetition frequency is multiplied step by step through the first-stage spatial Mach-Zehnder interferometer structure 31, the second-stage spatial Mach-Zehnder interferometer structure 32, and the third-stage spatial Mach-Zehnder interferometer structure 33. The first-stage spatial Mach-Zehnder interferometer structure 31 produces a first-order multiplied laser pulse signal, the second-stage spatial Mach-Zehnder interferometer structure 32 produces a second-order multiplied laser pulse signal, and the third-stage spatial Mach-Zehnder interferometer structure 33 produces a third-order multiplied laser pulse signal. The third-order multiplied laser pulse signal is then output as a multi-order multiplied laser pulse signal. The cascaded spatial Mach-Zehnder interferometer structure 3 can also increase the number of spatial Mach-Zehnder interferometer structures. For example, a fourth-order spatial Mach-Zehnder interferometer structure can be configured. The fourth-order spatial Mach-Zehnder interferometer structure obtains a laser pulse signal multiplied by four orders and outputs the laser pulse signal multiplied by four orders as a multi-order multiplied laser pulse signal.

[0026] In a preferred implementation of this invention, such as Figure 2 As shown, the first-stage spatial Mach-Zehnder interferometer structure 31, the second-stage spatial Mach-Zehnder interferometer structure 32, and the third-stage spatial Mach-Zehnder interferometer structure 33 all include: Half-wave plate, polarizing beam splitter, first quarter-wave plate, first mirror, second quarter-wave plate and second mirror; The half-wave plate is located on the first side of the polarizing beam splitter, the first quarter-wave plate is located on the second side of the polarizing beam splitter, the second quarter-wave plate is located on the third side of the polarizing beam splitter, the first mirror is located on the side of the first quarter-wave plate facing away from the polarizing beam splitter, and the second mirror is located on the side of the second quarter-wave plate facing away from the polarizing beam splitter; the first side, the second side, and the third side are adjacent to each other in sequence.

[0027] Specifically, the structure formed by cascading multiple spatial Mach-Zehnder interferometer structures can use the same components. Each spatial Mach-Zehnder interferometer structure includes a half-wave plate, a polarizing beam splitter, a first quarter-wave plate, a first mirror, a second quarter-wave plate, and a second mirror. The first-order spatial Mach-Zehnder interferometer structure 31 includes a half-wave plate 311, a polarizing beam splitter 312, a first quarter-wave plate 313, a first mirror 314, a second quarter-wave plate 315, and a second mirror 316. The second-order spatial Mach-Zehnder interferometer structure 32 includes a half-wave plate 321, a polarizing beam splitter 322, a first quarter-wave plate 323, a first mirror 324, a second quarter-wave plate 325, and a second mirror 326. The third-order spatial Mach-Zehnder interferometer structure 33 includes a half-wave plate 331, a polarizing beam splitter 331, a first quarter-wave plate 333, a first mirror 334, a second quarter-wave plate 335, and a second mirror 336. The first quarter-wave plate and the first reflector are located on the same side of the polarizing beam splitter, and the first quarter-wave plate is located between the first reflector and the polarizing beam splitter; the second quarter-wave plate and the second reflector are located on the same side of the polarizing beam splitter, and the second quarter-wave plate is located between the second reflector and the polarizing beam splitter.

[0028] The first side, second side, third side, and fourth side are adjacent to each other in sequence. The first side is the incident light side of the polarizing beam splitter, the second side is the reflected light side of the polarizing beam splitter, the third side is the transmitted light side of the polarizing beam splitter, and the fourth side is the output light side of the polarizing beam splitter.

[0029] In a preferred implementation of this invention, such as Figure 2 As shown, the half-wave plate 321 of the second-stage spatial Mach-Zehnder interference structure 32 is located on the fourth side of the polarization beam splitter 312 of the first-stage spatial Mach-Zehnder interference structure 31.

[0030] Specifically, the components of each level of the spatial Mach-Zehnder interferometer structure are identical, but the positions of the components in different levels of the spatial Mach-Zehnder interferometer structure are not entirely the same. In the second-level spatial Mach-Zehnder interferometer structure 32, the first side of the polarization beam splitter 322 corresponds to the fourth side of the polarization beam splitter 312 in the first-level spatial Mach-Zehnder interferometer structure 31. The half-wave plate 321 of the second-level spatial Mach-Zehnder interferometer structure 32 is located between the fourth side of the polarization beam splitter 312 in the first-level spatial Mach-Zehnder interferometer structure 31 and the first side of the polarization beam splitter 322 in the second-level spatial Mach-Zehnder interferometer structure 32.

[0031] In a preferred implementation of this invention, such as Figure 2As shown, the half-wave plate 331 of the third-level spatial Mach-Zehnder interference structure 33 is located on the fourth side of the polarization beam splitter 322 of the second-level spatial Mach-Zehnder interference structure 32.

[0032] Specifically, the first side of the polarization beam splitter 332 in the third-order spatial Mach-Zehnder interferometer structure 33 corresponds to the fourth side of the polarization beam splitter 322 in the second-order spatial Mach-Zehnder interferometer structure 32, and the half-wave plate 331 of the third-order spatial Mach-Zehnder interferometer structure 33 is located between the fourth side of the polarization beam splitter 322 in the second-order spatial Mach-Zehnder interferometer structure 32 and the first side of the polarization beam splitter 332 in the third-order spatial Mach-Zehnder interferometer structure 33.

[0033] In a preferred implementation of this invention, such as Figure 2 As shown, the length difference between the two arms of the first-stage spatial Mach-Zehnder interferometer structure 31 is: L1 = c / (2×f1); Where L1 represents the difference in length between the two arms of the first-order spatial Mach-Zehnder interference structure, c represents the speed of light, and f1 represents the repetition frequency of the spatial parallel light.

[0034] Specifically, the length difference between the two arms of the first-order spatial Mach-Zehnder interference structure 31 is determined based on the repetition frequency of the spatial parallel light, which is also based on the repetition frequency of the laser pulse signal. After multiplication, the repetition frequency of the first-order multiplied laser pulse signal is twice the repetition frequency of the spatial parallel light.

[0035] In a preferred implementation of this invention, such as Figure 2 As shown, the length difference between the two arms of the second-stage spatial Mach-Zehnder interferometer structure 32 is: L2 = c / (2×f2); f2 = 2 × f1; Where L2 represents the difference in length between the two arms of the second-order spatial Mach-Zehnder interferometer, c represents the speed of light, and f2 represents the repetition frequency of the first-order multiplied laser pulse signal.

[0036] Specifically, the length difference between the two arms of the second-order spatial Mach-Zehnder interferometer structure 32 is determined based on the repetition frequency of the first-order multiplied laser pulse signal. After multiplication, the repetition frequency of the second-order multiplied laser pulse signal is twice the repetition frequency of the first-order multiplied laser pulse signal.

[0037] In a preferred implementation of this invention, such as Figure 2 As shown, the length difference between the two arms of the third-order spatial Mach-Zehnder interferometer structure 33 is: L3 = c / (2×f3); f3 = 2 × f2; Where L3 represents the difference in length between the two arms of the third-order spatial Mach-Zehnder interferometer, c represents the speed of light, and f3 represents the repetition frequency of the second-order multiplied laser pulse signal.

[0038] Specifically, the length difference between the two arms of the third-order spatial Mach-Zehnder interferometer structure 33 is determined based on the repetition frequency of the second-order multiplied laser pulse signal. After multiplication, the repetition frequency of the third-order multiplied laser pulse signal is twice the repetition frequency of the second-order multiplied laser pulse signal.

[0039] In a preferred implementation of this invention, such as Figure 2 As shown, the repetition frequency of the multi-stage amplified laser pulse signal is: f4 = 2 × f3; Where f4 represents the repetition frequency of the multiplied laser pulse signal.

[0040] In a preferred implementation of this invention, such as Figure 2 As shown, the fundamental frequency is f4; the frequency of the higher harmonics is n*f4, where n represents an integer; the frequency of the filtered radio frequency signal is k*f4, where k represents an integer. <n。

[0041] Specifically, the focused laser pulse signal is multiplied through multiple stages to obtain multiple radio frequency (RF) signals, such as the fundamental wave and higher harmonics. There can be multiple higher harmonics, each with a different frequency. RF filter 6 filters out a single RF signal from these multiple signals; for example, RF filter 6 filters out a single higher harmonic (the repetition frequency of the single higher harmonic is k*f4). Then, phase noise analyzer 7 measures the phase noise of the filtered single higher harmonic to obtain the phase noise L(k*f4), and the timing jitter J(f) of the laser pulse signal is obtained using the timing jitter-phase noise conversion formula.

[0042] like Figure 3 As shown, a comparison is made between the timing jitter result of the ultrafast laser (0.38 fs [10kHz, 10MHz]) measured according to an embodiment of the present invention and the timing jitter result of the ultrafast laser directly measured by the photodetector 5 (2.35 fs [10kHz, 10MHz]). Under the same measurement conditions, the measurement accuracy of the timing jitter measurement method of the ultrafast laser provided by the embodiment of the present invention is 6 times higher than that of the direct measurement by the photodetector 5.

[0043] Based on the timing jitter measuring device for lasers described in any of the above embodiments, the present invention also provides a preferred embodiment of a timing jitter measuring method for lasers.

[0044] like Figure 4 As shown, the timing jitter measurement method for a laser according to an embodiment of the present invention includes the following steps: Step S100: Based on the first optical collimator, convert the laser pulse signal output by the laser under test into spatially parallel light; Step S200: Based on the cascaded spatial Mach-Zehnder interference structure, the repetition frequency of the spatial parallel light is multiplied to obtain a multi-level multiplied laser pulse signal; Step S300: Based on the second optical collimator, the multi-stage multiplied laser pulse signal is focused to obtain a focused laser pulse signal; Step S400: Based on the photodetector, the focused laser pulse signal is converted into multiple radio frequency signals, including the fundamental frequency and higher harmonics; Step S500: Based on the radio frequency filter, filter out the higher harmonics from the radio frequency signal to obtain the filtered radio frequency signal; Step S600: Based on the phase noise analyzer, perform phase noise analysis on the filtered radio frequency signal to obtain the timing jitter of the laser pulse signal.

[0045] Specifically, the laser under test emits a laser pulse signal. First, a first optical collimator converts the emitted laser pulse signal into spatially parallel light. Then, a cascaded spatial Mach-Zehnder interferometer structure is used to multiply the repetition frequency of the spatially parallel light, resulting in a multi-stage multiplied laser pulse signal. A second optical collimator then focuses the multi-stage multiplied laser pulse signal to obtain a focused laser pulse signal. A photodetector converts the focused laser pulse signal into multiple radio frequency (RF) signals, including a fundamental frequency RF signal and higher harmonic RF signals. An RF filter filters out a single higher harmonic RF signal from the multiple RF signals, which is then used as the filtered RF signal. A phase noise analyzer performs phase noise analysis on the filtered RF signal to obtain the timing jitter of the laser pulse signal.

[0046] Step S200 specifically includes: Step S210: Based on the first-order spatial Mach-Zehnder interference structure, the spatial parallel light is multiplied by repetition frequency to obtain a first-order multiplied laser pulse signal; Step S220: Based on the second-order spatial Mach-Zehnder interferometer structure, the repetition frequency of the first-order multiplied laser pulse is multiplied to obtain a second-order multiplied laser pulse signal; Step S230: Based on the third-order spatial Mach-Zehnder interferometer structure, the repetition frequency of the second-order multiplied laser pulse is multiplied to obtain a multi-order multiplied laser pulse signal.

[0047] Specifically, the cascaded spatial Mach-Zehnder interferometer structure employs a three-stage cascaded spatial Mach-Zehnder interferometer structure, consisting of a first-stage, a second-stage, and a third-stage spatial Mach-Zehnder interferometer structure. The first-stage spatial Mach-Zehnder interferometer structure is used to multiply the repetition frequency of spatially parallel light, resulting in a first-stage multiplied laser pulse signal. The second-stage spatial Mach-Zehnder interferometer structure is then used to multiply the repetition frequency of this first-stage multiplied laser pulse, resulting in a second-stage multiplied laser pulse signal. Finally, the third-stage spatial Mach-Zehnder interferometer structure is used to multiply the repetition frequency of this second-stage multiplied laser pulse signal, resulting in a multi-stage multiplied laser pulse signal.

[0048] It should be understood that the application of the present invention is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A timing jitter measuring device for a laser, characterized in that, include: The first optical collimator is used to convert the laser pulse signal output by the laser under test into spatially parallel light; A cascaded spatial Mach-Zehnder interferometer structure is used to multiply the repetition frequency of the spatial parallel light to obtain a multiplied laser pulse signal. The second optical collimator is used to focus the multi-stage amplified laser pulse signal to obtain a focused laser pulse signal; A photodetector is used to convert a focused laser pulse signal into multiple radio frequency signals, including the fundamental frequency and higher harmonics. A radio frequency filter is used to filter out higher harmonics in the radio frequency signal to obtain the filtered radio frequency signal. A phase noise analyzer is used to perform phase noise analysis on the filtered radio frequency signal to obtain the timing jitter of the laser pulse signal.

2. The timing jitter measuring device for a laser according to claim 1, characterized in that, The cascaded spatial Mach-Zehnder interferometer structure includes: A first-order spatial Mach-Zehnder interferometer structure is used to multiply the repetition frequency of the spatial parallel light to obtain a first-order multiplied laser pulse signal. The second-order spatial Mach-Zehnder interferometer structure is used to multiply the repetition frequency of the first-order multiplied laser pulse to obtain a second-order multiplied laser pulse signal. A third-order spatial Mach-Zehnder interferometer structure is used to multiply the repetition frequency of the second-order multiplied laser pulse to obtain a multi-order multiplied laser pulse signal.

3. The timing jitter measuring device for a laser according to claim 2, characterized in that, The first-level spatial Mach-Zehnder interferometer structure, the second-level spatial Mach-Zehnder interferometer structure, and the third-level spatial Mach-Zehnder interferometer structure all include: Half-wave plate, polarizing beam splitter, first quarter-wave plate, first mirror, second quarter-wave plate and second mirror; The half-wave plate is located on the first side of the polarizing beam splitter, the first quarter-wave plate is located on the second side of the polarizing beam splitter, the second quarter-wave plate is located on the third side of the polarizing beam splitter, and the first mirror is located on the side of the first quarter-wave plate away from the polarizing beam splitter, and the second mirror is located on the side of the second quarter-wave plate away from the polarizing beam splitter. The first side, the second side, and the third side are adjacent to each other.

4. The timing jitter measuring device for a laser according to claim 3, characterized in that, The half-wave plate of the second-stage spatial Mach-Zehnder interferometer structure is located on the fourth side of the polarization beam splitter of the first-stage spatial Mach-Zehnder interferometer structure; The half-wave plate of the third-level spatial Mach-Zehnder interferometer structure is located on the fourth side of the polarization beam splitter of the second-level spatial Mach-Zehnder interferometer structure.

5. The timing jitter measuring device for a laser according to claim 3, characterized in that, The difference in length between the two arms of the first-order spatial Mach-Zehnder interferometer structure is: L1 = c / (2×f1); Where L1 represents the difference in length between the two arms of the first-order spatial Mach-Zehnder interference structure, c represents the speed of light, and f1 represents the repetition frequency of the spatial parallel light. The difference in length between the two arms of the second-order spatial Mach-Zehnder interferometer structure is: L2 = c / (2×f2); f2 = 2 × f1; Where L2 represents the difference in length between the two arms of the second-order spatial Mach-Zehnder interference structure, and f2 represents the repetition frequency of the first-order multiplied laser pulse signal; The difference in length between the two arms of the third-order spatial Mach-Zehnder interferometer structure is: L3 = c / (2×f3); f3 = 2 × f2; Where L3 represents the difference in length between the two arms of the third-order spatial Mach-Zehnder interferometer structure, and f3 represents the repetition frequency of the second-order multiplied laser pulse signal; The repetition frequency of the multi-stage amplified laser pulse signal is: f4 = 2 × f3; Where f4 represents the repetition frequency of the multiplied laser pulse signal.

6. The timing jitter measuring device for a laser according to claim 5, characterized in that, The fundamental frequency is f4; the frequency of the higher harmonics is n*f4, where n represents an integer; the frequency of the filtered radio frequency signal is k*f4, where k represents an integer. <n。 7. A method for measuring timing jitter in a laser, characterized in that, The timing jitter measurement method includes the following steps: Based on the first optical collimator, the laser pulse signal output by the laser under test is converted into spatially parallel light; Based on the cascaded spatial Mach-Zehnder interferometer structure, the repetition frequency of the spatial parallel light is multiplied to obtain a multi-level multiplied laser pulse signal; Based on the second optical collimator, the multi-stage amplified laser pulse signal is focused to obtain a focused laser pulse signal; Based on a photodetector, the focused laser pulse signal is converted into multiple radio frequency signals, including the fundamental frequency and higher harmonics; Based on the radio frequency filter, higher harmonics are filtered out from the radio frequency signal to obtain the filtered radio frequency signal; Based on a phase noise analyzer, the filtered radio frequency signal is subjected to phase noise analysis to obtain the timing jitter of the laser pulse signal.

8. The method for measuring timing jitter of a laser according to claim 7, characterized in that, The method based on a cascaded spatial Mach-Zehnder interferometer structure, which multiplies the repetition frequency of the spatially parallel light to obtain a multiplied laser pulse signal, includes: Based on the first-order spatial Mach-Zehnder interferometer structure, the repetition frequency of the spatial parallel light is multiplied to obtain a first-order multiplied laser pulse signal; Based on the second-order spatial Mach-Zehnder interferometer structure, the repetition frequency of the first-order multiplied laser pulse is multiplied to obtain a second-order multiplied laser pulse signal; Based on the third-order spatial Mach-Zehnder interferometer structure, the repetition frequency of the second-order multiplied laser pulse is multiplied to obtain a multi-order multiplied laser pulse signal.

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