Photon Doppler velocity measurement method and device based on multi-channel optical switch

Abstract

According to the photon Doppler speed measurement method and device based on the multi-channel optical switch, speed measurement of a large number of speed measurement points is achieved only through a single device, and speed measurement of the large number of points has feasibility in technology; speed signal retest of a large number of speed measurement points can be realized only by adding one recording channel, and the hidden danger of test data loss caused by oscilloscope and channel faults can be effectively reduced; optical heterodyne speed measurement can be realized at all speed measurement points, and the time resolution and the measurement precision of the speed can be improved by utilizing up-conversion heterodyne; in addition, the bandwidth requirement of the system can be reduced by using down-conversion heterodyne, the two modes are easy to replace, and the multi-channel optical switch is adopted for beam combination and is separated by channel isolation, so that the speed signal crosstalk of all measuring points can be effectively eliminated.

Description

Technical Field

[0001] The invention relates to the technical field of laser speed measurement, and in particular to a photon Doppler speed measurement method and device based on a multi-channel optical switch. Background Art

[0002] In the research fields of shock wave and detonation physics, explosives, high-intensity lasers, pulse power, ultra-high-speed experiments, astrophysics, weapons, etc., velocity has always been the most critical issue and the main parameter that needs to be diagnosed, such as continuous and non-contact measurement of the free surface velocity history of various materials under the action of shock waves, measurement of the velocity of flyers driven by loading technologies such as explosives, light gas guns, laser devices, and electromagnetic drives, and measurement of the velocity and acceleration of shells in artillery and shell launching systems.

[0003] Photonic Doppler Velocimetry (PDV, also known as DPS or DISAR in China) has the advantages of non-contact measurement, high time resolution, and high velocity measurement accuracy. It has been widely used and has become the main means of velocity measurement.

[0004] The existing laser velocity measurement technology can only measure a limited number of points on the object to be measured, but with the deepening of related research, the requirement of array-type or area coverage velocity measurement of a large number of points on the object to be measured has been proposed, such as simultaneous velocity measurement of multiple objects, spatiotemporal inhomogeneity of strong shock waves, velocity change history of each point on the target surface loaded by laser or electromagnetic over time, velocity distribution and relative difference of the entire surface of the sample at one or more moments, etc. The development trend of laser velocity measurement technology has also put forward the same requirement, and defined the new optical velocity measurement equipment that realizes this requirement as the latest generation of optical velocity measurement equipment. At present, my country has a clear and urgent demand for this.

[0005] In traditional speed measuring equipment such as PDV, one measuring point requires at least one recording channel (including one detector and one oscilloscope channel), and generally one speed measuring host can only measure 4 to 8 speed measuring points at most. The measurement of more points needs to be achieved by superimposing multiple hosts. However, with the increase in the number of speed measuring points, the complexity, cost and volume of the entire system (especially the recording channel) increase significantly. Therefore, it is difficult to use the simple superposition method of PDV to achieve speed measurement of a large number of points (dozens or even hundreds of points), and other speed measuring technologies have more prominent problems in this regard. Summary of the invention

[0006] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a photon Doppler velocity measurement method and device based on a multi-channel optical switch, which is specifically achieved through the following technical solutions:

[0007] The present invention provides a photon Doppler speed measuring device based on a multi-channel optical switch, comprising:

[0008] N detection light lasers of different wavelengths, each of which is used to output detection light, and the N detection light lasers output N detection lights of different wavelengths in total;

[0009] N optical fiber beam splitters, which are connected to the output end of the detection light laser, and each optical fiber beam splitter is used to split the connected single detection light beam into M detection lights; the N optical fiber beam splitters divide the N detection lights into M×N detection lights;

[0010] M wavelength division multiplexers A, M circulators, M wavelength division multiplexers B and M×N speed measuring probes, one of the light paths separated by each optical fiber beam splitter is inputted to each wavelength division multiplexer A without duplication, each wavelength division multiplexer A combines N light paths from N optical fiber beam splitters into one light path, and then splits the light path into N light paths through the circulator and the wavelength division multiplexer B, and then enters N different speed measuring probes; since the N optical fiber beam splitters divide the N detection lights into M×N detection lights, the M wavelength division multiplexers A combine the M×N detection lights into M lights, the M circulators and the M wavelength division multiplexers B divide the M lights into M×N lights, and the M×N lights enter the M×N speed measuring probes respectively, and then shine on the moving target to be measured, forming M×N speed measuring points;

[0011] N speed measuring probes return signal lights with speed information, which are then multiplexed into a group of signal lights through wavelength division multiplexer B and circulator in sequence; M×N speed measuring point speed measuring probes return M×N signal lights, which are then multiplexed into M groups of signal lights;

[0012] Each group of signal lights is amplified by the amplifier and delayed by the delay line before entering the M-channel optical switch; the M-channel optical switch keeps one channel of the first to M-th input channels connected in chronological order, so that only one group of signal lights is output at one time, and M groups of signal lights separated by different delay times are output at multiple times; the M-channel optical switch inputs the signal lights into a 2×2 optical fiber coupler;

[0013] N reference lasers, the wavelengths of the N reference lasers correspond one to one with the wavelengths of the N detection light lasers; the N reference lights output by the N reference lasers are multiplexed and power-adjusted by the wavelength division multiplexer C and combined into one light, which is input to the 2×2 fiber coupler;

[0014] The 2×2 fiber coupler interferes with the two lights and forms an interference light through wavelength division multiplexing. The interference light enters detector 1 and detector 2 respectively through two pigtails; detector 1 converts the interference light into a voltage signal and inputs it to oscilloscope 1; detector 2 converts the interference light into a voltage signal and inputs it to oscilloscope 2; oscilloscope 1 and oscilloscope 2 respectively record and process the received voltage signals to realize speed measurement and remeasurement of M×N speed measurement points.

[0015] Optionally or preferably, the number of the detection light lasers is N; the optical fiber splitter is used to split the detection light into M pieces; wherein, M×N is recommended to be no less than 4.

[0016] Optionally or preferably, the oscilloscope one and the oscilloscope two are two channels of one oscilloscope, or may be a channel of different oscilloscopes respectively.

[0017] The present invention provides a photon Doppler velocity measurement method based on a multi-channel optical switch, comprising the following steps:

[0018] S1, N detection light lasers emit N detection lights;

[0019] S2, splitting N detection lights through N optical fiber beam splitters, each detection light is divided into M detection lights, and the N detection lights are divided into M×N detection lights in total;

[0020] S3, inputting the M paths of light split by each optical fiber beam splitter into M different wavelength division multiplexers A respectively, that is, each wavelength division multiplexer A simultaneously receives N paths of light from N optical fiber beam splitters; the wavelength division multiplexer A multiplexes the received light beams and outputs them as one path of light;

[0021] S4. The output optical path of each wavelength division multiplexer A is split by a circulator and a wavelength division multiplexer B. The output optical path of each wavelength division multiplexer A is divided into N paths. M circulators and M wavelength division multiplexers B split M different wavelength division multiplexers A into M×N paths of light. The M×N paths of light are respectively input into M×N speed measuring probes and irradiated onto the moving target to be measured, forming M×N speed measuring points.

[0022] S5. The surface of the moving target to be measured will reflect the detection light. Based on the Doppler frequency shift, the speed of the moving target to be measured will cause the reflected detection light to carry the speed information of the moving target to be measured. The reflected detection light is the signal light.

[0023] S6, the speed measuring probe collects signal lights from M×N speed measuring points, and multiplexes the M×N signal lights into M groups of signal lights through M wavelength division multiplexers B and M circulators;

[0024] S7, amplifying the M groups of signal lights obtained in step S6;

[0025] S8, performing equal delay on the M groups of signal lights processed in step S7;

[0026] S9, inputting the M groups of signal lights processed in step S8 into an M-channel optical switch, which couples them into one light beam and inputs them into a 2×2 optical fiber coupler;

[0027] S10, a 2×2 optical fiber coupler receives the light beam processed in step S9 and the multi-wavelength reference light beam set, interferes the two beams, and forms an interference light beam through wavelength division multiplexing; and sends the interference light beam to detector 1 and detector 2 respectively through two pigtail fibers;

[0028] S11, detector 1 and detector 2 respectively receive the interference light generated in step S10, and convert it into voltage signals respectively;

[0029] S12, oscilloscope 1 and oscilloscope 2 receive the voltage signals from detector 1 and detector 2 respectively, and record and process them respectively, so as to realize speed measurement and re-measurement of M×N speed measurement points.

[0030] Optionally or preferably, in step S8, when the M groups of signal lights are equally delayed, specifically:

[0031] The first group of signal lights is not delayed, so that the first group of signal lights is directly used as the subsequent input; a group of delay lines is added to the optical channel of the second group of signal lights, so that the second group of signal lights is delayed by ΔT and used as the subsequent input;

[0032] …

[0033] Add M-2 groups of delay lines to the optical channel of the M-1 group of signal light, so that the M-1 group of signal light is delayed by (M-2)×ΔT and used as subsequent input;

[0034] An M-1 group of delay lines is added to the optical channel of the M-th group of signal light, so that the M-th group of signal light is delayed by (M-1)×ΔT and used as subsequent input.

[0035] Optionally or preferably, the multi-wavelength reference beam set is generated by the following steps:

[0036] T1. Configure N reference light lasers so that the N reference light lasers emit N reference lights, and the wavelengths of the reference lights correspond one to one with the wavelengths of the DC detection lights in step S1, that is:

[0037] λ iR =λ i +Δi

[0038] Among them, λ iR is the wavelength of the reference light emitted by the i-th reference laser; iis the wavelength of the DC detection light emitted by the i-th detection light laser; Δi is the wavelength difference between the i-th reference laser and the i-th detection light laser, and Δi belongs to the i-th item in the monotonic sequence {Δn}: Δ1, Δ2, …, Δn;

[0039] T2, multiplexing the reference light generated in step T1 through a dense wavelength division multiplexer C;

[0040] T3. Adjust the power of the reference light generated in step T2 by an adjustable attenuator to obtain a multi-wavelength reference beam.

[0041] Optionally or preferably, the step S12 comprises the following steps:

[0042] S121, oscilloscope 1 receives the voltage signal from detector 1 and records it as the main measurement signal;

[0043] S122, oscilloscope 1 multiplexes each group of voltage signals with speed information into a group of time division signals by wavelength division multiplexing method, and at the same time, each wavelength division signal in the group is sequentially separated in the longitudinal direction; M groups of voltage signals are multiplexed into M groups of time division signals;

[0044] S123, each group of time-division signals contains speed signals of N speed measurement points, and each group of time-division signals is separated in sequence in the horizontal direction, and after all the M groups of time-division signals are expanded, speed signals of M×N speed measurement points can be obtained;

[0045] S124, oscilloscope 2 receives and records the voltage signal from detector 2;

[0046] S125, performing time-frequency processing on the voltage signal received by the second oscilloscope to obtain a speed spectrum of M×N speed measurement points, thereby realizing signal re-measurement.

[0047] Based on the above technical solution, the following technical effects can be produced:

[0048] 1. A single device can be used to measure the speed of M×N speed measurement points, making speed measurement at a large number of points technically feasible;

[0049] 2. Only two recording channels are needed to achieve speed signal retesting of M×N speed measurement points, which can effectively reduce the risk of test data loss due to oscilloscope and channel failure, significantly increase reliability, and set different amplitude ranges to improve test results. Conventional devices and methods require 2×M×N detectors and 2×M×N oscilloscope channels to achieve signal retesting of the same number of measurement points;

[0050] 3. All M×N speed measurement points can realize optical heterodyne speed measurement, that is, up-conversion heterodyne can be used to improve the time resolution and measurement accuracy of the speed, and down-conversion heterodyne can be used to reduce the bandwidth requirements of the system, and the two methods are easy to switch;

[0051] 5. Each group of time-division signals contains multiple speed signals of multiple wavelengths (rather than the conventional single wavelength or single speed signal). The speed signals in the group are isolated by wavelength differences. Each group of time-division signals is combined by a multi-channel optical switch and separated by its channel isolation, so that the speed signal crosstalk of all measuring points can be effectively eliminated. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0053] Figure 1 It is a schematic diagram of the structural connection of the detection light laser, the detection light output optical path and the signal light return optical path;

[0054] Figure 2 It is a schematic diagram of the structural connection of the multiplexed optical path and the signal recording part;

[0055] Figure 3 The wavelength division and time division joint multiplexed speed measurement signals of M×N speed measurement points obtained for one recording channel (wavelength division multiplexing in the vertical direction and time division multiplexing in the horizontal direction). DETAILED DESCRIPTION

[0056] It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.

[0057] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0058] Embodiment 1:

[0059] like Figure 1-Figure 3 As shown:

[0060] The present invention provides a photon Doppler speed measuring device based on a multi-channel optical switch, comprising:

[0061] N detection light lasers of different wavelengths, each of which is used to output detection light, and the N detection light lasers output N detection lights of different wavelengths in total;

[0062] N optical fiber beam splitters, which are connected to the output end of the detection light laser, and each optical fiber beam splitter is used to split the connected single detection light beam into M detection lights; the N optical fiber beam splitters divide the N detection lights into M×N detection lights;

[0063] M wavelength division multiplexers A, M circulators, M wavelength division multiplexers B and M×N speed measuring probes, one of the light paths separated by each optical fiber beam splitter is inputted to each wavelength division multiplexer A without duplication, each wavelength division multiplexer A combines N light paths from N optical fiber beam splitters into one light path, and then splits the light path into N light paths through the circulator and the wavelength division multiplexer B, and then enters N different speed measuring probes; since the N optical fiber beam splitters divide the N detection lights into M×N detection lights, the M wavelength division multiplexers A combine the M×N detection lights into M lights, the M circulators and the M wavelength division multiplexers B divide the M lights into M×N lights, and the M×N lights enter the M×N speed measuring probes respectively, and then shine on the moving target to be measured, forming M×N speed measuring points;

[0064] N speed measuring probes return signal lights with speed information, which are then multiplexed into a group of signal lights through wavelength division multiplexer B and circulator in sequence; M×N speed measuring point speed measuring probes return M×N signal lights, which are then multiplexed into M groups of signal lights;

[0065] Each group of signal lights is amplified by an amplifier and delayed by a delay line before entering an M-channel optical switch; the M-channel optical switch keeps one channel of the first to M-th input channels connected in sequence according to the time sequence, so that only one group of signal lights is output at one time, and M groups of signal lights separated by different delay times are output in sequence at multiple times; the M-channel optical switch inputs the signal lights into a 2×2 optical fiber coupler; specifically, the typical value of the isolation between each channel of the M-channel optical switch is not less than 20 dB, so the M groups of signal lights will not crosstalk with each other;

[0066] N reference lasers, the wavelengths of the N reference lasers correspond one to one with the wavelengths of the N detection light lasers; the N reference lights output by the N reference lasers are multiplexed and power-adjusted by the wavelength division multiplexer C and combined into one light, which is input to the 2×2 fiber coupler;

[0067] The 2×2 optical fiber coupler interferes with two paths of light and forms an interference light beam through wavelength division multiplexing, and the interference light enters detector 1 and detector 2 respectively through two pigtails; detector 1 converts the interference light into a voltage signal and inputs it to oscilloscope 1; detector 2 converts the interference light into a voltage signal and inputs it to oscilloscope 2; oscilloscope 1 and oscilloscope 2 respectively record and process the received voltage signals to realize speed measurement and re-measurement of M×N speed measurement points, wherein oscilloscope 1 and oscilloscope 2 are two channels of one oscilloscope, and can also be one channel of different oscilloscopes.

[0068] Specifically, M×N is recommended to be no less than 4; for example, N and M can be 4 or 8.

[0069] The present invention also provides a photon Doppler velocity measurement method based on a multi-channel optical switch, comprising the following steps:

[0070] S1, N detection light lasers emit N detection lights;

[0071] S2, splitting N detection lights through N optical fiber beam splitters, each detection light is divided into M detection lights, and the N detection lights are divided into M×N detection lights in total;

[0072] S3, inputting the M paths of light split by each optical fiber beam splitter into M different wavelength division multiplexers A respectively, that is, each wavelength division multiplexer A simultaneously receives N paths of light from N optical fiber beam splitters; the wavelength division multiplexer A multiplexes the received light beams and outputs them as one path of light;

[0073] S4. The output optical path of each wavelength division multiplexer A is split by a circulator and a wavelength division multiplexer B. The output optical path of each wavelength division multiplexer A is divided into N paths. M circulators and M wavelength division multiplexers B split M different wavelength division multiplexers A into M×N paths of light. The M×N paths of light are respectively input into M×N speed measuring probes and irradiated onto the moving target to be measured, forming M×N speed measuring points.

[0074] S5. The surface of the moving target to be measured will reflect the detection light. Based on the Doppler frequency shift, the speed of the moving target to be measured will cause the reflected detection light to carry the speed information of the moving target to be measured. The reflected detection light is the signal light.

[0075] S6, the speed measuring probe collects signal lights from M×N speed measuring points, and multiplexes the M×N signal lights into M groups of signal lights through M wavelength division multiplexers B and M circulators;

[0076] S7, amplifying the M groups of signal lights obtained in step S6;

[0077] S8, performing equal delay on the M groups of signal lights processed in step S7;

[0078] S9, inputting the M groups of signal lights processed in step S8 into an M-channel optical switch, which couples them into one light beam and inputs them into a 2×2 optical fiber coupler;

[0079] S10, a 2×2 optical fiber coupler receives the light beam processed in step S9 and the multi-wavelength reference light beam set, interferes the two beams, and forms an interference light beam through wavelength division multiplexing; and sends the interference light beam to detector 1 and detector 2 respectively through two pigtail fibers;

[0080] S11, detector 1 and detector 2 respectively receive the interference light generated in step S10, and convert it into voltage signals respectively;

[0081] S12, oscilloscope 1 and oscilloscope 2 receive the voltage signals from detector 1 and detector 2 respectively, and record and process them respectively, so as to realize speed measurement and re-measurement of M×N speed measurement points.

[0082] In this embodiment, when the M groups of signal lights are equally delayed in step S8, specifically:

[0083] The first group of signal lights is not delayed, so that the first group of signal lights is directly used as the subsequent input; a group of delay lines is added to the optical channel of the second group of signal lights, so that the second group of signal lights is delayed by ΔT and used as the subsequent input;

[0084] …

[0085] Add M-2 groups of delay lines to the optical channel of the M-1 group of signal light, so that the M-1 group of signal light is delayed by (M-2)×ΔT and used as subsequent input;

[0086] An M-1 group of delay lines is added to the optical channel of the M-th group of signal light, so that the M-th group of signal light is delayed by (M-1)×ΔT and used as subsequent input.

[0087] In this embodiment, the multi-wavelength reference beam set is generated by the following steps:

[0088] T1. Configure N reference light lasers so that the N reference light lasers emit N reference lights, and the wavelengths of the reference lights correspond one to one with the wavelengths of the DC detection lights in step S1, that is:

[0089] λ iR =λ i +Δi

[0090] Among them, λ iR is the wavelength of the reference light emitted by the i-th reference laser; i is the wavelength of the DC detection light emitted by the i-th detection light laser; Δi is the wavelength difference between the i-th reference laser and the i-th detection light laser, and Δi belongs to the i-th item in the monotonic sequence {Δn}: Δ1, Δ2, …, Δn; further, the sequence {Δn} is an arithmetic increasing sequence or an unequally increasing sequence;

[0091] T2, multiplexing the reference light generated in step T1 through a dense wavelength division multiplexer C;

[0092] T3. Adjust the power of the reference light generated in step T2 by an adjustable attenuator to obtain a multi-wavelength reference beam.

[0093] Furthermore, when the wavelength of the reference light is longer (i.e., the above Δi is a positive value), it is an up-conversion heterodyne speed measurement, there is an initial static speed that is not zero (its value corresponds to Δi), and the speed curve in the dynamic stage increases on its basis (up to the speed value corresponding to the system bandwidth), thereby improving the time resolution and measurement accuracy. When the wavelength of the reference light is shorter (i.e., the above Δi is a negative value), it is a down-conversion heterodyne speed measurement, there is also an initial static speed that is not zero (its value corresponds to Δi), and the speed curve in the dynamic stage first decreases to zero and then increases on its basis (up to the speed value corresponding to the system bandwidth), thereby increasing the speed measurement range, or reducing the system bandwidth requirement when the speed measurement range is the same.

[0094] In this embodiment, step S12 includes the following steps:

[0095] S121, oscilloscope 1 receives the voltage signal from detector 1 and records it as the main measurement signal;

[0096] S122, oscilloscope 1 multiplexes each group of voltage signals with speed information into a group of time division signals by wavelength division multiplexing method, and at the same time, each wavelength division signal in the group is sequentially separated in the longitudinal direction; M groups of voltage signals are multiplexed into M groups of time division signals;

[0097] S123, each group of time-division signals contains speed signals of N speed measurement points, and each group of time-division signals is separated in sequence in the horizontal direction, and after all the M groups of time-division signals are expanded, speed signals of M×N speed measurement points can be obtained;

[0098] S124, oscilloscope 2 receives and records the voltage signal from detector 2;

[0099] S125, perform time-frequency processing on the voltage signal received by the second oscilloscope to obtain Figure 3 The speed spectrum of the M×N speed measurement points shown in the figure can realize signal remeasurement.

[0100] The velocity spectrum produced by the first set of interference is as follows Figure 3 As shown, it can be seen that because {Δn}: Δ1, Δ2, ..., Δn is an increasing series, the speed curves of the speed measurement points 1-1, 2-1, ..., N-1 change in turn based on static speeds of different sizes, that is, through the wavelength division multiplexing method, the speed signals of N speed measurement points are multiplexed into the first group of time division signals of the speed spectrum;

[0101] After the time corresponding to the first group of delay lines, the second group of N wavelengths of signal light 1-2, 2-2, ..., N-2 enters the 2×2 fiber coupler at the same time. After the same process as the first group, the speed signals of the N speed measurement points are multiplexed into the second group of time-division signals of the speed spectrum, such as Figure 3 As shown, and the time corresponding to the first group of delay lines is spaced apart from the first group of time-division signals;

[0102] The third group of N wavelength signal lights (1-3, 2-3, ..., N-3) to the Mth group of N wavelength signal lights (1-M, 2-M, ..., NM) are multiplexed into the third group of time division signals to the Mth group of time division signals of the velocity spectrum through the same process as the second group, such as Figure 3 As shown, the time interval of the delay line and the time of the difference in its length correspond to the preceding time division signal;

[0103] By analogy, the speed signals of M×N speed measurement points are finally recorded in one signal through wavelength division multiplexing and time division multiplexing, and have retesting provided by another detector and oscilloscope, which effectively reduces the hidden danger of test data loss due to oscilloscope and channel failure, and different amplitude ranges can be set to improve the test effect.

[0104] The above is only a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the concept described herein through the above teachings or the technology or knowledge of the relevant field. The changes and modifications made by those skilled in the art shall not deviate from the spirit and scope of the present invention, and shall be within the scope of protection of the claims attached to the present invention.

Claims

1. A photon Doppler speed measurement device based on a multi-channel optical switch, characterized in that: include: N detection light lasers of different wavelengths, each of which is used to output detection light, and the N detection light lasers output N detection lights of different wavelengths in total; N optical fiber beam splitters, each of which is connected to the output end of the detection light laser, and each optical fiber beam splitter is used to split the received single detection light beam into M detection lights; N optical fiber beam splitters divide N detection lights into M×N detection lights; M wavelength division multiplexers A, M circulators, M wavelength division multiplexers B and M×N speed measuring probes, one of the light paths separated by each optical fiber beam splitter is inputted to each wavelength division multiplexer A without duplication, each wavelength division multiplexer A combines N light paths from N optical fiber beam splitters into one light path, and then splits the light path into N light paths through the circulator and the wavelength division multiplexer B, and then enters N different speed measuring probes; since the N optical fiber beam splitters divide the N detection lights into M×N detection lights, the M wavelength division multiplexers A combine the M×N detection lights into M lights, the M circulators and the M wavelength division multiplexers B divide the M lights into M×N lights, and the M×N lights enter the M×N speed measuring probes respectively, and then shine on the moving target to be measured, forming M×N speed measuring points; N speed measuring probes return signal lights with speed information, which are then multiplexed into a group of signal lights through wavelength division multiplexer B and circulator in sequence; M×N speed measuring point speed measuring probes return M×N signal lights, which are then multiplexed into M groups of signal lights; Each group of signal light enters the M-channel optical switch after being amplified by the amplifier and delayed by the delay line; The M-channel optical switch keeps one channel of the 1st to Mth input channels connected in chronological order, so that only one group of signal lights is output at one time, and M groups of signal lights separated by different delay times are output at multiple times; the M-channel optical switch inputs the signal light into a 2×2 optical fiber coupler; N reference lasers, the wavelengths of the N reference lasers correspond one to one with the wavelengths of the N detection light lasers; the N reference lights output by the N reference lasers are multiplexed and power-adjusted by the wavelength division multiplexer C and combined into one light, which is input to the 2×2 fiber coupler; The 2×2 fiber coupler interferes with the two lights and forms an interference light through wavelength division multiplexing. The interference light enters detector 1 and detector 2 respectively through two pigtails; detector 1 converts the interference light into a voltage signal and inputs it to oscilloscope 1; detector 2 converts the interference light into a voltage signal and inputs it to oscilloscope 2; oscilloscope 1 and oscilloscope 2 respectively record and process the received voltage signals to realize speed measurement and remeasurement of M×N speed measurement points.

2. The photon Doppler velocity measurement device based on a multi-channel optical switch according to claim 1, characterized in that: The number of the detection light lasers is N; the optical fiber beam splitter is used to split the detection light into M pieces; wherein M×N is not less than 4.

3. The photon Doppler velocity measurement device based on a multi-channel optical switch according to claim 1, characterized in that: The oscilloscope 1 and the oscilloscope 2 are two channels of one oscilloscope; they may also be a channel of different oscilloscopes.

4. A photon Doppler velocity measurement method based on a multi-channel optical switch, characterized in that: The following steps are involved: S1, N detection light lasers emit N detection lights; S2, splitting N detection lights through N optical fiber beam splitters, each detection light is divided into M detection lights, and the N detection lights are divided into M×N detection lights in total; S3, inputting the M paths of light split by each optical fiber beam splitter into M different wavelength division multiplexers A respectively, that is, each wavelength division multiplexer A simultaneously receives N paths of light from N optical fiber beam splitters; the wavelength division multiplexer A multiplexes the received light beams and outputs them as one path of light; S4. The output optical path of each wavelength division multiplexer A is split by a circulator and a wavelength division multiplexer B. The output optical path of each wavelength division multiplexer A is divided into N paths. M circulators and M wavelength division multiplexers B split M different wavelength division multiplexers A into M×N paths of light. The M×N paths of light are respectively input into M×N speed measuring probes and irradiated onto the moving target to be measured, forming M×N speed measuring points. S5. The surface of the moving target to be measured will reflect the detection light. Based on the Doppler frequency shift, the speed of the moving target to be measured will cause the reflected detection light to carry the speed information of the moving target to be measured. The reflected detection light is the signal light. S6, the speed measuring probe collects signal lights from M×N speed measuring points, and multiplexes the M×N signal lights into M groups of signal lights through M wavelength division multiplexers B and M circulators; S7, amplifying the M groups of signal lights obtained in step S6; S8, performing equal delay on the M groups of signal lights processed in step S7; S9, inputting the M groups of signal lights processed in step S8 into an M-channel optical switch, which couples them into one light beam and inputs them into a 2×2 optical fiber coupler; S10, a 2×2 optical fiber coupler receives the light beam processed in step S9 and the multi-wavelength reference light beam set, interferes the two beams, and forms an interference light beam through wavelength division multiplexing; and sends the interference light beam to detector 1 and detector 2 respectively through two pigtail fibers; S11, detector 1 and detector 2 respectively receive the interference light generated in step S10, and convert it into voltage signals respectively; S12, oscilloscope 1 and oscilloscope 2 receive the voltage signals from detector 1 and detector 2 respectively, and record and process them respectively, so as to realize speed measurement and re-measurement of M×N speed measurement points.

5. The photon Doppler velocity measurement method based on a multi-channel optical switch according to claim 4, characterized in that: When the M groups of signal lights are equally delayed in step S8, specifically: The first group of signal lights is not delayed, so that the first group of signal lights is directly used as the subsequent input; a group of delay lines is added to the optical channel of the second group of signal lights, so that the second group of signal lights is delayed by ΔT and used as the subsequent input; …… Add M-2 groups of delay lines to the optical channel of the M-1 group of signal light, so that the M-1 group of signal light is delayed by (M-2)×ΔT and used as subsequent input; An M-1 group of delay lines is added to the optical channel of the M-th group of signal light, so that the M-th group of signal light is delayed by (M-1)×ΔT and used as subsequent input.

6. The photon Doppler velocity measurement method based on a multi-channel optical switch according to claim 4, characterized in that: The multi-wavelength reference beam set is generated by the following steps: T1. Configure N reference light lasers so that the N reference light lasers emit N reference lights, and the wavelengths of the reference lights correspond one to one with the wavelengths of the DC detection lights in step S1, that is: l iR =λ i +Dn Among them, λ iR is the wavelength of the reference light emitted by the i-th reference laser; i is the wavelength of the DC detection light emitted by the i-th detection light laser; Δi is the wavelength difference between the i-th reference laser and the i-th detection light laser, and Δi belongs to the i-th item in the monotonic sequence {Δn}: Δ1, Δ2, …, Δn; T2, multiplexing the reference light generated in step T1 through a dense wavelength division multiplexer; T3. Adjust the power of the reference light generated in step T2 by an adjustable attenuator to obtain a multi-wavelength reference beam.

7. The photon Doppler velocity measurement method based on a multi-channel optical switch according to claim 4, characterized in that: The step S12 comprises the following steps: S121, oscilloscope 1 receives the voltage signal from detector 1 and records it as the main measurement signal; S122, oscilloscope 1 multiplexes each group of voltage signals with speed information into a group of time division signals by wavelength division multiplexing method, and at the same time, each wavelength division signal in the group is sequentially separated in the longitudinal direction; M groups of voltage signals are multiplexed into M groups of time division signals; S123, each group of time-division signals contains speed signals of N speed measurement points, and each group of time-division signals is separated in sequence in the horizontal direction, and after all the M groups of time-division signals are expanded, speed signals of M×N speed measurement points can be obtained; S124, oscilloscope 2 receives and records the voltage signal from detector 2; S125, performing time-frequency processing on the voltage signal received by the second oscilloscope to obtain a speed spectrum of M×N speed measurement points, thereby realizing signal re-measurement.

Images