A portable laser doppler wind lidar

Abstract

The application discloses a portable laser Doppler wind measurement radar, adopts a layered three-dimensional structure design, narrow linewidth laser and pump laser are arranged on a bottom plate to form a bottom layer, components on a parallel light path plate form a parallel light path layer, optical switches on an optical switch control plate form an optical switch control layer, components on a vertical light path plate form a vertical light path layer, data acquisition cards on a data acquisition card mounting plate form a data acquisition card layer, a front end plate forms a port panel layer, and a rear end plate where a control circuit is located forms a circuit control layer. The application can greatly improve the space and energy consumption effective utilization rate, simultaneously solves the electromagnetic crosstalk problem existing in miniaturization, and realizes low power consumption and miniaturization of the laser wind measurement radar.

Description

Technical Field

[0001] This invention relates to wind measurement technology, specifically to a portable laser Doppler wind measuring radar, belonging to the fields of laser wind measuring radar and coherent detection technology. Background Technology

[0002] The measurement of wind field information is one of the important tasks in the research and application of meteorology and aerodynamics. Lightweight, low-power, and high-precision wind field detection systems are of great significance for new energy development, national defense construction, and flight safety.

[0003] Laser Doppler wind radar is a detection system based on Mach-Zehnder or Michelson optical interferometry structure. It features high measurement accuracy, high resolution, wide detection range, and fast response speed. It mainly consists of core components such as narrow linewidth light source, optical amplifier, optical switch, balanced detector, fiber optic acousto-optic modulator, fiber optic beam splitter, fiber optic attenuator, fiber optic isolator, and data acquisition card.

[0004] Currently, the main method used is to modulate the optical signal using a fiber optic acousto-optic modulator before amplification (e.g., ...). Figure 1 (as shown) or the signal is amplified and then passed through an optical fiber acousto-optic modulator (such as...). Figure 2 (As shown) Two structural forms.

[0005] Figure 1 The final output of the method shown will generate more spontaneous emission noise, which will affect the detection range. Figure 2 The method shown can greatly reduce the time-domain noise of spontaneous emission, but the loss of the acousto-optic modulator itself will lead to insufficient final output optical power, affecting the detection range.

[0006] Existing laser Doppler wind radars all use discrete components assembled in a flat manner, resulting in a generally large size. Currently, the smallest unit on the market that includes all components such as narrow linewidth light sources, optical amplifiers, optical switches, fiber optic acousto-optic modulators, fiber optic beam splitters, fiber optic attenuators, and fiber optic isolators has a size of 180mm × 150mm × 45mm, a weight of approximately 3kg, and a power consumption of over 20W, making it difficult to meet the requirements for portable applications. Summary of the Invention

[0007] To address the issues of low space and energy utilization in existing laser Doppler wind radars that employ discrete components and independently integrated functional parts, this invention aims to provide a portable laser Doppler wind radar. This invention proposes a miniaturized system design method for laser wind radar, significantly improving space and energy efficiency while resolving electromagnetic crosstalk issues during miniaturization, thus achieving low power consumption and miniaturization of the laser wind radar.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A portable laser Doppler wind radar includes a narrow-linewidth laser, a pump laser, and a control circuit. The output of the narrow-linewidth laser is connected to the input of a 1*2 beam splitter I. One output of the 1*2 beam splitter I is sequentially connected to an optical fiber acousto-optic modulator I, a wavelength division multiplexer I, a gain fiber I, a polarization-maintaining isolator I, an optical fiber acousto-optic modulator II, a wavelength division multiplexer II, a gain fiber II, a polarization-maintaining isolator II, an optical fiber circulator, and an optical switch. The other output of the 1*2 beam splitter I is connected to one input of a 2*2 beam splitter via an optical attenuator. The output of the optical fiber circulator is connected to the other input of the 2*2 beam splitter. The two outputs of the 2*2 beam splitter are connected to a balanced detector, and the output of the balanced detector is connected to a data acquisition card. The output of the pump laser is connected to the input of the 1*2 beam splitter II, and the two outputs of the 1*2 beam splitter II are connected to the pump input terminals of wavelength division multiplexer I and wavelength division multiplexer II, respectively. The control circuit is connected to the narrow linewidth laser, the pump laser, the fiber acousto-optic modulator I, the fiber acousto-optic modulator II, the optical switch, the optical attenuator, the balanced detector, and the data acquisition card, respectively.

[0009] Furthermore, it also includes a rectangular shell, which is formed by a bottom plate, a left side plate, a right side plate, a front end plate, a rear end plate, and a cover plate. The narrow linewidth laser and the pump laser are fixed to the upper surface of the base plate in a staggered manner; the drive circuits of the two fiber acousto-optic modulators are distributed back to back on both sides of the base plate to avoid crosstalk. A horizontal parallel optical path plate is fixed inside the housing above the bottom plate. Two fiber optic acousto-optic modulators are fastened side by side to the upper surface of the parallel optical path plate. 1*2 beam splitter I, 1*2 beam splitter II, wavelength division multiplexer I, wavelength division multiplexer II and polarization maintaining isolator I are fixed in the corresponding grooves on the upper surface of the parallel optical path plate. The optical attenuator and its control circuit are fixed to one corner of the upper surface of the parallel optical path plate. The inner side of one of the left and right side plates forms a vertical optical path plate, and the balanced detector is fixed on the vertical optical path plate; the fiber optic circulator, polarization maintaining isolator II and 2*2 beam splitter are fixed in the corresponding grooves of the vertical optical path plate.

[0010] Furthermore, a horizontal optical switch control board is fixedly installed inside the housing above the parallel optical path board. The optical switch is inverted on the lower surface of the optical switch control board by pin welding. The optical switch is located directly above wavelength division multiplexer I and wavelength division multiplexer II, and is located in the space between the two fiber optic acousto-optic modulators of the parallel optical path board.

[0011] Furthermore, a horizontal data acquisition card mounting plate is fixedly installed inside the housing above the optical switch control board, and the data acquisition card is mounted on the data acquisition card mounting plate.

[0012] Furthermore, the outer surface of the front-end board is provided with a communication port, a control port, and an optical output port; the control circuit is installed on the inner surface of the rear-end board to form a circuit control layer.

[0013] Furthermore, the fiber optic pigtail of the pump laser is led out directly from an opening on one side of the narrow-linewidth laser after passing through a slot on the narrow-linewidth laser; the fiber optic pigtail of the narrow-linewidth laser faces the pump laser, and after entering the pump laser, it turns 180° and is led out from the opening of the pump laser to the same direction as the fiber optic pigtail of the pump laser; a groove is provided at the edge of the narrow-linewidth laser housing to fix the fiber optic pigtail of the narrow-linewidth laser; the fiber optic pigtails of the pump laser and the narrow-linewidth laser are bent upwards and face the parallel optical path plate and connected to the corresponding 1*2 beam splitter.

[0014] Furthermore, wavelength division multiplexer I and wavelength division multiplexer II are arranged side by side and centered between the two fiber optic acousto-optic modulators; 1*2 beam splitter I and 1*2 beam splitter II are arranged laterally at the same end of the two fiber optic acousto-optic modulators and close to the end of the parallel optical path plate; polarization maintaining isolator I is located at the other end of the two fiber optic acousto-optic modulators and close to the other end of the parallel optical path plate opposite to the two 1*2 beam splitters.

[0015] Furthermore, several mounting supports are provided on the upper surface of the base plate, and the parallel optical path board is suspended above the base plate through the mounting supports; several mounting feet are provided on the upper surface of the optical switch control board, and the data acquisition card mounting plate is fixedly mounted above the optical switch control board through the mounting feet.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention adopts a layered three-dimensional structure design and the concept of integrating functional component circuits and optical paths, which greatly improves the space and energy utilization rate, while separating electromagnetic interference sources and reducing the impact of electromagnetic crosstalk. 2. Compared with the existing technology of direct optical amplification, the present invention adopts a cross-interconnection method of dual AOM and dual EDF. Cross-interconnected multi-stage optical amplification can improve the maximum output optical power. At the same time, the second AOM can filter out the temporal domain noise of the first-stage EDFA amplification, thus suppressing ASE noise as a whole.

[0017] 3. Single-pump source beam splitting achieves N (N≥2) level optical amplification, improving pump efficiency and reducing the number of pump lasers from N to 1, significantly reducing the size of the optical amplification unit and lowering power consumption. 4. Placing the high-power, high-heat pump laser and the narrow-linewidth laser at the bottom of the housing, with them arranged opposite each other and in a staggered manner, facilitates heat dissipation and reduces the thermal impact on other components. The inverted optical switch fully utilizes the remaining space in the parallel optical path layer, further improving space utilization.

[0018] Through the above improvements, the present invention can reduce the size of the laser wind radar to 130mm*80mm*40mm, which is only 1 / 3 of the original size. The volume is greatly reduced, the power consumption is less than 12W, the weight is less than 1kg, the single pulse energy is greater than 5μJ, and various performance indicators are significantly improved. With the external optical lens, three-dimensional vector wind field information measurement can be realized, which meets the portable laser wind measurement needs of fields such as UAVs and digital fire control systems. Attached Figure Description

[0019] Figure 1 - Schematic diagram of an existing laser Doppler wind radar system embodiment 1 (optical signal modulated by an optical fiber acousto-optic modulator and then amplified).

[0020] Figure 2 - Schematic diagram of an existing laser Doppler wind radar system embodiment 2 (optical signal amplified and then modulated by an optical fiber acousto-optic modulator).

[0021] Figure 3 - Schematic diagram of the laser Doppler wind measurement radar system of this invention.

[0022] Figure 4 - Layout diagram of the bottom pump laser and narrow linewidth laser of this invention.

[0023] Figure 5 - Layout diagram of the parallel optical path layer device of this invention.

[0024] Figure 6 - Layout diagram of the vertical optical path layer device of this invention.

[0025] Figure 7 -Layout diagram of the optical switch control layer of this invention.

[0026] Figure 8 - External dimensions of an embodiment of the portable laser wind-measuring radar of the present invention.

[0027] Figure 9 -Schematic diagram of the portable laser wind measuring radar of the present invention.

[0028] Figure 10 - Test results of the portable laser wind measuring radar of this invention. Detailed Implementation

[0029] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0030] The portable laser Doppler wind measuring radar of this invention has the following system principle: Figure 3As shown, it includes a narrow linewidth laser ①, a 1*2 beam splitter Ⅰ ②, an optical fiber acousto-optic modulator Ⅰ ③, a wavelength division multiplexer Ⅰ ④, a gain fiber Ⅰ ⑤, a polarization-maintaining isolator Ⅰ ⑥, an optical fiber acousto-optic modulator Ⅱ ⑦, a wavelength division multiplexer Ⅱ ⑧, a gain fiber Ⅱ ⑨, a polarization-maintaining isolator Ⅱ ⑩, an optical fiber circulator ⑪, an optical switch ⑫, an optical attenuator ⑬, a pump laser ⑭, a 1*2 beam splitter Ⅱ ⑮, a 2*2 beam splitter ⑯, a balanced detector ⑰, a data acquisition card ⑱, and a control circuit. The output of the narrow linewidth laser ① is connected to the input of the 1*2 beam splitter Ⅰ ②; one output of the 1*2 beam splitter Ⅰ ② is connected in sequence to the fiber acousto-optic modulator Ⅰ ③, wavelength division multiplexer Ⅰ ④, gain fiber Ⅰ ⑤, polarization-maintaining isolator Ⅰ ⑥, fiber acousto-optic modulator Ⅱ ⑦, wavelength division multiplexer Ⅱ ⑧, gain fiber Ⅱ ⑨, polarization-maintaining isolator Ⅱ ⑩, fiber circulator ⑪, and optical switch ⑫; the other output of the 1*2 beam splitter Ⅰ ② is connected to one input of the 2*2 beam splitter ⑯ through the optical attenuator ⑬; the output of the fiber circulator ⑪ is connected to the other input of the 2*2 beam splitter ⑯; the two outputs of the 2*2 beam splitter ⑯ are connected to the balanced detector ⑰, and the output of the balanced detector ⑰ is connected to the data acquisition card ⑱.

[0031] The output of pump laser ⑭ is connected to the input of 1*2 beam splitter Ⅱ⑮, and the two outputs of 1*2 beam splitter Ⅱ⑮ are connected to the pump input terminals of wavelength division multiplexer Ⅰ④ and wavelength division multiplexer Ⅱ⑧, respectively.

[0032] The control circuit is connected to the narrow linewidth laser ①, the pump laser ⑭, the fiber acousto-optic modulator Ⅰ ③, the fiber acousto-optic modulator Ⅱ ⑦, the optical switch ⑫, the optical attenuator ⑬, the balanced detector ⑰, and the data acquisition card ⑱, respectively.

[0033] This laser wind-measuring radar uses an external optical lens connected to an optical switch (⑫) for laser emission and return light reception. The attenuation of the optical attenuator (⑬) in this invention is adjustable.

[0034] To mount and fix the aforementioned components of the wind-measuring radar, forming a ready-to-use product, this invention also includes a rectangular housing, which is composed of six sides: a bottom plate, a left side plate, a right side plate, a front end plate, a rear end plate, and a cover plate. This invention employs a layered, three-dimensional structural design, thereby compactly, reliably, and with some isolation, mounting the aforementioned components inside the housing. The specific distribution of each component is as follows.

[0035] See Figure 4The narrow-linewidth laser ① and the pump laser ⑭ are fixed to the upper surface of the base plate opposite each other and offset (by screws). During installation, the fiber optic pigtail of the pump laser ⑭ passes through a slot on the narrow-linewidth laser ① and exits directly from opening A on one side of the narrow-linewidth laser ①. The fiber optic pigtail of the narrow-linewidth laser ① faces the pump laser ⑭. After entering the pump laser, the fiber optic pigtail of the narrow-linewidth laser turns 180° and exits from opening B of the pump laser to the right side, facing the same direction as the pump laser's fiber optic pigtail. Simultaneously, a groove is provided at edge C of the narrow-linewidth laser ①'s housing to secure its fiber optic pigtail. The fiber optic pigtails of both the pump laser and the narrow-linewidth laser are bent upwards towards the parallel optical path plate and connected to the corresponding 1*2 beam splitter. The dashed arrows in the diagram indicate the fiber optic direction.

[0036] Since the left-side rear panel is the circuit control layer, wire soldering and circuit debugging are required later. To avoid mutual interference between the optical path and the circuit during subsequent assembly and debugging, the output fiber pigtails of both the narrow-linewidth laser ① and the pump laser ⑭ are led out from the right side facing the front panel (away from the rear panel). To reduce the assembly volume (length and width) of the narrow-linewidth laser ① and the pump laser ⑭, they are arranged in a relative configuration, with the output heads of the narrow-linewidth laser ① and the pump laser ⑭ respectively intersecting within their housings.

[0037] The drive circuits of the two fiber optic acousto-optic modulators are distributed back-to-back on both sides of the base plate to avoid crosstalk.

[0038] See Figure 5 Inside the housing, above the base plate, is a horizontal parallel optical path board. Two fiber optic acousto-optic modulators ③ and ⑦ are fastened side by side (by screws) to the upper surface of the parallel optical path board. 1*2 beam splitter I ②, 1*2 beam splitter II ⑮, wavelength division multiplexer I ④, wavelength division multiplexer II ⑧, and polarization maintaining isolator I ⑥ are fixed to the corresponding grooves on the upper surface of the parallel optical path board with 703 adhesive. Optical attenuator ⑬ and its control circuit (by screws) are fixed to one corner of the upper surface of the parallel optical path board.

[0039] Further, see also Figure 5 Wavelength division multiplexer I ④ and wavelength division multiplexer II ⑧ are arranged side by side and centered between the two fiber optic acousto-optic modulators; 1*2 beam splitter I ② and 1*2 beam splitter II ⑮ are arranged laterally at the same end of the two fiber optic acousto-optic modulators and close to the end of the parallel optical path plate; polarization maintaining isolator I ⑥ is located at the other end of the two fiber optic acousto-optic modulators and close to the other end of the parallel optical path plate opposite to the two 1*2 beam splitters.

[0040] See Figure 6The inner side of one of the left and right side plates forms a vertical optical path plate. The balanced detector ⑰ is fixed to the vertical optical path plate with screws. The fiber optic circulator ⑪, polarization maintaining isolator Ⅱ ⑩ and 2*2 beam splitter ⑯ are fixed to the corresponding grooves in the vertical optical path plate with 703 glue.

[0041] Furthermore, a horizontal optical switch control board is fixedly installed inside the housing above the parallel optical path board, see [reference]. Figure 7 The optical switch ⑫ is inverted and soldered to the lower surface of the optical switch control board via pins. The optical switch ⑫ is located directly above wavelength division multiplexers I ④ and II ⑧, and within the space between the two fiber acousto-optic modulators ③ and ⑦ on the parallel optical path board. This inverted optical switch design allows for full utilization of the remaining space in the parallel optical path layer, further improving space utilization.

[0042] Furthermore, a horizontal data acquisition card mounting plate is fixedly installed inside the housing above the optical switch control board, and the data acquisition card (18) is mounted on the data acquisition card mounting plate.

[0043] This invention uses a front-end board as a port panel layer. The outer surface of the front-end board is provided with a communication port, a control port, and an optical output port. The control port is used for power input and control; the communication port is used for data communication with a host computer; and the optical output port is used to output pulsed laser light and receive the returned light. The control circuit is mounted on the inner surface of the rear-end board to form a circuit control layer.

[0044] This invention employs a layered, three-dimensional structural design concept to achieve a compact structure and reduced volume. The components on the base plate constitute the bottom layer (see...). Figure 4 The components on the parallel optical path board constitute the parallel optical path layer (see...). Figure 5 The optical switches on the optical switch control board constitute the optical switch control layer (see...). Figure 7 The components on the vertical optical path board constitute the vertical optical path layer (see...). Figure 6 The data acquisition cards on the data acquisition card mounting board constitute the data acquisition card layer; the front-end board constitutes the port panel layer; and the back-end board containing the control circuit constitutes the circuit control layer. This invention arranges components in layers based on the functional division and assembly sequence of the wind measurement radar optical path system. Furthermore, the specific arrangement of components is based on their input / output and fiber optic line routing, achieving a compact layout, convenient connection, and interference avoidance.

[0045] To ensure reliable mounting of the various mounting plates within the housing, this invention provides several mounting supports on the upper surface of the base plate, through which the parallel optical path plate is suspended and mounted above the base plate. Several mounting feet are provided on the upper surface of the optical switch control plate, through which the data acquisition card mounting plate is suspended and fixedly mounted above the optical switch control plate.

[0046] The main inventive points of this invention are briefly described below: 1. The layered three-dimensional modular design provides power and control for other active components as a separate module. The optical path is divided into a parallel optical path layer and a vertical optical path layer. The optical fiber and the wire are spatially separated to avoid interference. The wire is concentrated on one side of the module and connected to the control circuit.

[0047] 2. To address the heat dissipation and electromagnetic crosstalk issues arising from the layered three-dimensional structure design and high-density integration, the high-power, high-heat pump laser and narrow-linewidth laser are placed at the bottom layer for easy heat dissipation. The AOM driving circuits are distributed back-to-back on both sides to avoid crosstalk, and the AOM matching circuits are shielded to prevent electromagnetic interference.

[0048] 3. A cross-amplification scheme is adopted for multi-stage optical amplification. First, the output of fiber acousto-optic modulator I③ is pre-amplified and then input into fiber acousto-optic modulator II⑦. Then, the output of fiber acousto-optic modulator II⑦ is subjected to two-stage optical amplification. Compared with the existing direct optical amplification scheme, this can significantly improve the maximum output optical power and suppress ASE noise. At the same time, the optical amplifier path is integrated with the system optical path. The two-stage gain fibers share a single pump laser. A single pump source is used for N (N≥2)-stage beam splitting to achieve N-stage optical amplification by pumping the multi-stage gain fiber. The number of pump lasers is reduced from N to 1, which is more economical and has lower power consumption.

[0049] 4. The pump laser and the narrow linewidth laser are arranged opposite each other and offset (offset range: 5-20mm), see [reference]. Figure 4 Both output optical fibers and pigtails are led out from the same side and connected to the upper parallel optical path layer.

[0050] 5. The optical switch ⑫ and its control board are placed upside down above the parallel optical path layer. The optical switch ⑫ is located in the space between the two AOMs of the parallel optical path layer, see [link / reference]. Figure 7 The front of the optical switch control board can be used as an optical path platform for fiber optic connections.

[0051] Through the above improvements, the present invention achieves a miniaturized and low-power target for the laser Doppler wind radar system. Except for the optical antenna, the system size can reach 130mm×80mm×40mm, and the power consumption is <12W.

[0052] Figure 8 This is a schematic diagram showing the external dimensions of an embodiment of a portable laser wind-measuring radar based on a layered three-dimensional structure design. Figure 8 As can be seen, apart from the optical antenna, the system size can be reduced to 130mm×80mm×40mm. Figure 9 for Figure 8A schematic diagram of the corresponding embodiment: where A: bottom layer; B: parallel optical path layer; C: optical switch control layer; D: data acquisition card layer; E: vertical optical path layer; F: port panel layer; G: circuit control layer; H: side panel; I: cover plate.

[0053] Figure 10 for Figure 8 The diagram shows the test results of the wind-measuring radar in the illustrated embodiment. This invention can detect vector wind field information within a 3km range.

[0054] The above embodiments of the present invention are merely illustrative examples and are not intended to limit the implementation of the invention. Those skilled in the art can make various changes and modifications based on the above description. It is impossible to exhaustively list all possible implementations here. All obvious changes or modifications derived from the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. A portable laser Doppler wind-measuring radar, characterized in that: It includes a narrow-linewidth laser, a pump laser, and a control circuit. The output of the narrow-linewidth laser is connected to the input of a 1*2 beam splitter I. One output of the 1*2 beam splitter I is connected sequentially to fiber acousto-optic modulator I, wavelength division multiplexer I, gain fiber I, polarization-maintaining isolator I, fiber acousto-optic modulator II, wavelength division multiplexer II, gain fiber II, polarization-maintaining isolator II, fiber circulator, and optical switch. The other output of the 1*2 beam splitter I is connected to one input of a 2*2 beam splitter through an optical attenuator. The output of the fiber circulator is connected to the other input of the 2*2 beam splitter. The two outputs of the 2*2 beam splitter are connected to a balanced detector, and the output of the balanced detector is connected to a data acquisition card. The output of the pump laser is connected to the input of the 1*2 beam splitter II, and the two outputs of the 1*2 beam splitter II are connected to the pump input terminals of wavelength division multiplexer I and wavelength division multiplexer II, respectively. The control circuit is connected to the narrow linewidth laser, the pump laser, the fiber acousto-optic modulator I, the fiber acousto-optic modulator II, the optical switch, the optical attenuator, the balanced detector, and the data acquisition card, respectively. It also includes a rectangular shell, which is formed by a bottom plate, a left side plate, a right side plate, a front end plate, a rear end plate and a cover plate. The narrow linewidth laser and the pump laser are fixed to the upper surface of the base plate in a staggered manner; the drive circuits of the two fiber acousto-optic modulators are distributed back to back on both sides of the base plate to avoid crosstalk. A horizontal parallel optical path plate is fixed inside the housing above the bottom plate. Two fiber optic acousto-optic modulators are fastened side by side to the upper surface of the parallel optical path plate. 1*2 beam splitter I, 1*2 beam splitter II, wavelength division multiplexer I, wavelength division multiplexer II and polarization maintaining isolator I are fixed in the corresponding grooves on the upper surface of the parallel optical path plate. The optical attenuator and its control circuit are fixed to one corner of the upper surface of the parallel optical path plate. The inner side of one of the left and right side plates forms a vertical optical path plate, and the balanced detector is fixed on the vertical optical path plate; the fiber optic circulator, polarization maintaining isolator II and 2*2 beam splitter are fixed in the corresponding grooves of the vertical optical path plate.

2. The portable laser Doppler wind radar according to claim 1, characterized in that: A horizontal optical switch control board is fixedly installed inside the housing above the parallel optical path board. The optical switch is inverted on the lower surface of the optical switch control board by pin welding. The optical switch is located directly above wavelength division multiplexer I and wavelength division multiplexer II, and is located in the space between the two fiber acousto-optic modulators of the parallel optical path board.

3. The portable laser Doppler wind radar according to claim 2, characterized in that: A horizontal data acquisition card mounting plate is fixedly installed inside the housing above the optical switch control board, and the data acquisition card is mounted on the data acquisition card mounting plate.

4. A portable laser Doppler wind radar according to claim 1, characterized in that: The front-end board has communication ports, control ports and optical output ports on its outer surface; the control circuit is installed on the inner surface of the rear-end board to form a circuit control layer.

5. A portable laser Doppler wind radar according to claim 1, characterized in that: The fiber optic pigtail of the pump laser is led out directly from an opening on one side of the narrow-linewidth laser after passing through a slot on the narrow-linewidth laser. The fiber optic pigtail of the narrow-linewidth laser faces the pump laser. After entering the pump laser, the fiber optic pigtail of the narrow-linewidth laser turns 180° and is led out from the opening of the pump laser to the same direction as the fiber optic pigtail of the pump laser. A groove is provided at the edge of the narrow-linewidth laser housing to fix the fiber optic pigtail of the narrow-linewidth laser. The fiber optic pigtails of the pump laser and the narrow-linewidth laser are bent upwards and then face the parallel optical path plate and are connected to the corresponding 1*2 beam splitter.

6. A portable laser Doppler wind radar according to claim 1, characterized in that: Wavelength division multiplexer I and wavelength division multiplexer II are arranged side by side and centered between the two fiber acousto-optic modulators; 1*2 beam splitter I and 1*2 beam splitter II are arranged laterally at the same end of the two fiber acousto-optic modulators and close to the end of the parallel optical path plate; polarization maintaining isolator I is located at the other end of the two fiber acousto-optic modulators and close to the other end of the parallel optical path plate opposite to the two 1*2 beam splitters.

7. A portable laser Doppler wind radar according to claim 1, characterized in that: Several mounting supports are provided on the upper surface of the base plate, and the parallel optical path board is suspended above the base plate through the mounting supports; several mounting feet are provided on the upper surface of the optical switch control board, and the data acquisition card mounting plate is fixedly mounted above the optical switch control board through the mounting feet.

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