WO2023019498A1 - 一种基于dwdm光开关模块测量三维风量的光路切换通道和切换方法、及激光雷达 - Google Patents

一种基于dwdm光开关模块测量三维风量的光路切换通道和切换方法、及激光雷达 Download PDF

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WO2023019498A1
WO2023019498A1 PCT/CN2021/113434 CN2021113434W WO2023019498A1 WO 2023019498 A1 WO2023019498 A1 WO 2023019498A1 CN 2021113434 W CN2021113434 W CN 2021113434W WO 2023019498 A1 WO2023019498 A1 WO 2023019498A1
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laser
optical switch
signal
switch module
dwdm
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PCT/CN2021/113434
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English (en)
French (fr)
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卢立武
肖增利
罗浩
李五一
乔乃燕
李智
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南京牧镭激光科技有限公司
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
    • G01P5/00—Measuring speed of fluids, e.g. of air stream; Measuring speed of bodies relative to fluids, e.g. of ship, of aircraft
    • G01P5/26—Measuring speed of fluids, e.g. of air stream; Measuring speed of bodies relative to fluids, e.g. of ship, of aircraft by measuring the direct influence of the streaming fluid on the properties of a detecting optical wave
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
    • G01P13/00—Indicating or recording presence, absence, or direction, of movement
    • G01P13/0006—Indicating or recording presence, absence, or direction, of movement of fluids or of granulous or powder-like substances
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
    • G01P13/00—Indicating or recording presence, absence, or direction, of movement
    • G01P13/02—Indicating direction only, e.g. by weather vane
    • G01P13/025—Indicating direction only, e.g. by weather vane indicating air data, i.e. flight variables of an aircraft, e.g. angle of attack, side slip, shear, yaw
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
    • G01S17/02—Systems using the reflection of electromagnetic waves other than radio waves
    • G01S17/50—Systems of measurement based on relative movement of target
    • G01S17/58—Velocity or trajectory determination systems; Sense-of-movement determination systems
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
    • G01S17/88—Lidar systems specially adapted for specific applications
    • G01S17/95—Lidar systems specially adapted for specific applications for meteorological use
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
    • G01S7/483—Details of pulse systems
    • G01S7/484—Transmitters
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/26—Optical coupling means
    • G02B6/28—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals
    • G02B6/293—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means
    • G02B6/29379—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means characterised by the function or use of the complete device
    • G02B6/2938—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means characterised by the function or use of the complete device for multiplexing or demultiplexing, i.e. combining or separating wavelengths, e.g. 1xN, NxM
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/11—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on acousto-optical elements, e.g. using variable diffraction by sound or like mechanical waves
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
    • Y02A90/00—Technologies having an indirect contribution to adaptation to climate change
    • Y02A90/10—Information and communication technologies [ICT] supporting adaptation to climate change, e.g. for weather forecasting or climate simulation

Definitions

  • the invention belongs to the technical field of three-dimensional air volume measurement equipment and methods, and in particular relates to a DWDM optical switch module-based measurement of three-dimensional air volume optical channels and a switching method, and a laser radar.
  • Coherent Doppler lidar uses the aerosol backscatter signal and the beat frequency signal of local oscillator light to obtain the Doppler frequency shift of the scattered signal, thereby obtaining wind speed information.
  • the inversion of the three-dimensional wind field requires wind speed values in at least three directions.
  • lidar measures wind speeds in multiple directions by scanning.
  • laser circulators only have a single output head, which can only measure a single radial wind speed, and cannot distinguish the state of a wind speed and wind direction in an area.
  • the existing optical switching methods are: (1) mechanical CDL structure, a scanner is installed in front of the telescope barrel, and there is an 8° optical wedge element in the center of the scanner, which will be refracted when light passes through the optical wedge.
  • the scanner rotates once, the scanned circle forms an inverted conical shape, and the laser radar forms a coordinate system in several directions in the scanning area.
  • a magneto-optical switch is connected behind the circulator.
  • the magneto-optic switch is an optical switch that uses the Faraday magneto-optic effect.
  • the effect of the magneto-optic crystal on the polarization plane of incident polarized light is changed by changing the external magnetic field. , to achieve the effect of optical path switching, and to send and receive laser light through telescopes with different orientations, so as to realize the detection of three-dimensional wind field.
  • This solution has small structure, fast switching speed, high stability, low driving voltage, small crosstalk, and long life time, but the price is relatively high, and additional signal control timing and temperature control are required to prevent the insertion loss of the device.
  • Micromechanical MEMS optical switch the light is focused on the mems vibrating mirror through the lens, and the vibrating mirror is electrically tuned to make it rotate in different directions, and then couple the light into the optical fiber array to achieve the effect of switching the optical channel.
  • This solution is cheap, less internal optical components and easy to integrate, the consistency of device parameters is better controlled, the production cycle is short, it can meet the needs of mass production, and the adjustable rate is high, but the MEMS chip is a semi-moving part, and the number of deflections has a life limit , 10 ⁇ 6 less than the magneto-optical switch, and its internal light spot is small, the device can withstand high peak power and low withstand power. It is necessary to provide an external circuit as a control signal, and it is easy to miss or not cut off the light during timing control.
  • the existing method uses MEMS optical switches, which have low power tolerance, which is not conducive to improving the performance of existing laser radars. It is easy to damage the pigtail by high power, resulting in increased insertion loss, or even no light, and the device is directly damaged; and the optical fiber array The film layer cannot withstand high power, the optical fiber is focused on the micro-vibrating mirror through the C-LENS lens, the temperature is very high, and the reflected light directly damages the film layer of the fiber array; the DWDM dense wavelength division multiplexer is a passive device.
  • the power can be customized, and the internal components can be damaged by laser coating to prevent the components from being broken down by high-power lasers and other corresponding problems during the radar performance improvement process, resulting in increased insertion loss and no light.
  • DWDM dense wavelength division multiplexer can use large mode field passive fiber and internal coating process to improve optical power input and output, so that the laser radar will be of great help to the improvement of future large energy.
  • the existing method uses a MEMS optical switch, which is sensitive to temperature, and the refractive index of the internal C-LENS lens changes.
  • MEMS optical switch which is sensitive to temperature, and the refractive index of the internal C-LENS lens changes.
  • the laser is coupled to the optical fiber array, it is easy to deviate, and it hits the surrounding glue to cause gasification, and the vaporization of the glue It will be attached to the fiber array, and the end face will be easily burned after the light passes through;
  • DWDM dense wavelength division multiplexer has a simple internal structure, is less affected by temperature, and has no lens coupling factors
  • the existing method uses MEMS optical switches, which require precise timing modulation of the circuit board, otherwise it is easy to miss the light cut, or the state of no light, causing the radar to detect wrong data, and the bit error rate is high;
  • DWDM dense wavelength division multiplexer which is a passive device, does not require external power supply and signal control. Through the internal filter and mirror structure, different wavelengths are screened and output from optical fibers of different wavelengths, so as to achieve the effect of switching channels.
  • the present invention proposes a new type of optical channel based on a DWDM switch module based on an adjustable seed laser + passive device DWDM (where DWDM is also called a dense wavelength division multiplexer).
  • DWDM is also called a dense wavelength division multiplexer.
  • a lidar with the above optical channel structure is further proposed.
  • lasers of different bands are given by adjustable seed lasers. After being amplified and passed through DWDM, they can be automatically distributed to the corresponding wavelength optical path, and then transmitted to the atmosphere through the telescope, and received at the same time. The echo signal of the atmosphere is also received from the corresponding channel, so as to obtain the wind speed information.
  • the present invention proposes an optical path switching channel based on a DWDM optical switch module for measuring three-dimensional air volume.
  • the optical switch module is used to distribute the channels in the optical path with different corresponding wavelengths, and it also includes the tunable seed source laser to output different wavelengths, which is realized by adjusting the current through the tunable seed drive.
  • the present invention also proposes a laser radar including the above-mentioned optical path switching channel.
  • the laser radar adopts the optical path switching channel described in claim 1, specifically including a tunable seed source laser, a tunable seed drive isolator, and a DWDM optical switch.
  • the tunable seed drive is used to assist the tunable seed source laser to emit laser light of different wavelengths; the tunable seed source laser is used to emit laser light of different wavelengths and send it to the isolator;
  • the isolator divides the laser into two paths, one path of laser light is processed by the DWDM optical switch module and the optical path of the telescope group, and is coupled and coherent with the other path of laser light in the coupler;
  • the photodetector is used to convert the coupled optical signal into an electrical signal, and output a difference frequency signal
  • the A/D data acquisition and signal processing module is connected to the output signal end of the photoelectric detector, and performs data processing to obtain time domain and frequency domain diagrams of the signal.
  • it also includes an acousto-optic modulator, a radio frequency driver, and a laser amplification module;
  • the video driver is used to output an external signal to the acousto-optic modulator;
  • the acousto-optic modulator is arranged at the output signal end of the isolator for The laser is modulated;
  • the laser amplification module is at the output signal end of the acousto-optic modulator, and is used to amplify the output light of the modulator to a suitable power.
  • it also includes a fiber optic circulator, including a plurality of ports, one port is used to receive the light emitted by the laser amplifier module, the second port is used to transmit signal light, and the third port is used to receive the light passing through the DWDM optical switch module, The telescope group returns the processed echo signal light.
  • a fiber optic circulator including a plurality of ports, one port is used to receive the light emitted by the laser amplifier module, the second port is used to transmit signal light, and the third port is used to receive the light passing through the DWDM optical switch module, The telescope group returns the processed echo signal light.
  • the present invention also provides the optical path switching method of the laser radar based on the DWDM optical switch module for measuring the three-dimensional air volume, and the specific steps are:
  • the pulsed laser interacts with the moving aerosol particles in the atmosphere, and the aerosol
  • the DWDM optical switch module divides the optical path into multiple channels.
  • the coordinate system it is defined that when ff 0 >0, the radial wind speed should be greater than 0, where the radial wind speed f: the total frequency of the received scattered signal; f AOM : the frequency of acousto-optic frequency shift, and the specific method of establishing the coordinate system: Divide the telescope into four parts, shoot into the atmosphere at different angles at the same time, follow the counterclockwise direction, and The upper right corner is the No.
  • the wind speed and direction of the upper beam plane are:
  • ⁇ up arctan 2(-y u ,-x u ).
  • the wind speed and direction of the lower beam plane are respectively:
  • ⁇ down arctan 2(-y d ,-x d )
  • ⁇ laser efficiency constant
  • ⁇ t horizontal telescope launch angle
  • ⁇ up upper plane beam angle
  • Vup upper plane wind speed
  • Vdown lower plane wind speed
  • ⁇ down lower plane beam angle
  • the index and turbulence state of the wind shear, as well as the wind speed state at different altitudes are calculated as follows:
  • STATUS(v los ) is the flag bit, ⁇ los : the wind speed label difference; Average wind speed; H lidar : radar installation height; X t : horizontal measurement distance; ⁇ s : vertical beam angle; H hub : hub height.
  • the technical content of the present invention is to use tunable seed source and DWDM dense wavelength division multiplexer to replace the original laser radar using optical switch method, which is a new type of optical channel switching method, specifically through the adjustable seed laser
  • optical switch method which is a new type of optical channel switching method, specifically through the adjustable seed laser
  • the lasers of different bands can be automatically distributed to the corresponding wavelength optical path after being amplified and passed through the DWDM optical switch module, and then sent to the atmosphere through the telescope, and the echo signal of the atmosphere is received at the same time, and the echo signal is also transmitted from the corresponding channel to receive wind speed information.
  • DWDM optical switch is used to replace the conventional MEMS optical switch.
  • DWDM does not require external power supply, nor does it need circuit timing control, low insertion loss, and low cost.
  • there is no need for external electrical signal control no need for an additional temperature control system, it can be integrated into miniaturization, it can output multiple channels, and the insertion loss is small. It can be customized and replaced with a large energy device, which is of great help to improve the performance of the radar.
  • the insertion loss refers to the insertion loss, which is the ratio of the input optical power of the fiber output head to the output optical power, specifically expressed as:
  • FIG. 1 is a schematic structural diagram of the laser radar of the present invention.
  • Fig. 2 is a schematic diagram of the composition and structure of the DWDM wavelength division multiplexer of the present invention.
  • Fig. 3 is a working principle diagram of the tunable seed source laser of the present invention.
  • Fig. 4 is a diagram of the aggregation relationship of the four beams of the lidar according to the present invention.
  • the specific structure of the lidar based on the DWDM optical switch module of the present invention to measure the three-dimensional air volume is:
  • Tunable seed source laser 1 used to output continuous laser light with different wavelengths.
  • Tunable seed drive 2 used to modulate different wavelengths of the seed source laser 1.
  • Isolator 3 prevent the return light from returning to the tunable laser 1, and protect the tunable seed source laser 1 from damage; and divide the tunable seed source laser into two paths of local oscillator light and signal light.
  • Acousto-optic modulator 4 The continuous light output by the isolator 3, after passing through the acousto-optic modulator 4, performs pulse modulation to form a pulsed laser, and the frequency changes accordingly and moves (the amount of frequency shift depends on the used acousto-optic modulator 4 Frequency of).
  • RF driver 5 output the external signal to the acousto-optic modulator 4 for modulation.
  • Laser amplification module 6 amplify the output light of the modulator to a suitable power for detection.
  • Optical fiber circulator 7 There are three ports in total, one port receives the light emitted by the amplification module, the second port transmits signal light, and the third port receives echo signal light.
  • DWDM dense wavelength division multiplexer also known as DWDM optical switch module 8: After outputting lasers of different wavelengths to the telescope through different channels, they are emitted into the atmosphere, and receive the lasers of the atmosphere through the co-location of transceivers echo signal.
  • Telescope group 9 focus the energy at the desired atmospheric distance, while receiving the signal of laser backscatter in the atmosphere.
  • Coupler 10 Coupling the local oscillator light output by the isolator 2 and the circulator echo signal of the fiber amplifier 5 for coherence, and splitting the coherent laser light into two beams and outputting them to the balance detector 8 .
  • Photodetector 11 Beat the two beams of coherent light coupled by 7, convert the beat optical signal into an electrical signal, and output a difference frequency signal.
  • A/D data acquisition and signal processing module 12 convert the continuous analog signal output by the balanced photodetector 8 into a discrete digital signal, perform data processing, and obtain time domain and frequency domain diagrams of the signal.
  • the specific test method using the above-mentioned laser radar is:
  • the laser passes through the isolator 3, which can also be a splitter, and then split all the way to the local oscillator light. As a beat frequency, one path is used as signal light on the main optical path.
  • the radar circuit board provides a synchronous modulation signal to the radio frequency driver 5, and the radio frequency driver 5 modulates the signal to the acousto-optic modulator 4, and the signal light passes through the acousto-optic modulator 4. , is modulated into a pulsed laser and generates a frequency shift f AOM corresponding to the frequency of the acousto-optic modulator 4 .
  • the optical fiber amplifier 6 is amplified to the power required for detection; the output pulse amplified laser is input from the first port of the optical fiber circulator 7, output from the second port of the optical fiber circulator 7, and connected to the DWDM optical switch module 8 for channel switching of different wavelengths After the telescope group 8 is launched onto the aerosol in the atmosphere, after the laser encounters the aerosol, there will be a backscattering effect.
  • the backscattering signal is received by the telescope group 9 and passed through the optical fiber circulator 7; the return light signal and One of the local oscillators of the splitter/isolator 3 is coupled to the coupler 10, and is coherently beat and divided into two beams; the two beams of coherently beat optical signals are input to the photodetector 11, and the photodetector 11 converts the light The signal is converted into an electrical signal and input to the A/D data acquisition and signal processing module 12 .
  • the tunable seed drive 2 adjusts the tunable seed source laser 1 to emit laser light with different wavelengths through the following settings: the laser has a sampling grating at both ends of the resonant cavity as a reflection grating.
  • the grating intervals of the two sampling gratings are designed to be slightly different.
  • the resulting spectrum will have different modes spaced apart. Only the modes that are on the reflection peaks of the two fibers at the same time can form the resonant amplification of light.
  • the injection current to move the reflection spectrum of one of the gratings, the overlapping position of the reflection peaks can be changed, thereby obtaining output light of different frequencies.
  • there is a first-order phase area in the middle which is also used as a fine adjustment area. Through this area, the oscillation position of each mode is changed to realize quasi-continuous wavelength adjustment.
  • the range can reach hundreds of nanometers, and the wavelength selection is finer.
  • wavelength accuracy affects wind velocity accuracy.
  • DWDM optical switch module 8 also known as DWDM dense wavelength division multiplexer: it is similar to the integration of multiple WDM devices. After multiple wavelengths pass through the DWDM wavelength division multiplexer through the multimode fiber, the lasers of different wavelengths are separated by the wavelength division multiplexer. Several wavelength combined lasers modulated by DBR tunable seed source lasers are coupled to DWDM optical devices through optical fibers. Only when the wavelength of light is within the filtering range can it enter the optical fiber through the filter and emit it; otherwise, it cannot pass through the filter of this wavelength and will be reflected back by the filter. At this time, a reflective film is coated on the edge of the module.
  • the light reflected by the first filter is reflected to the port of the next fiber array again, and filters of different wavelengths are also placed on the next port. After repeated actions in sequence, after finding the appropriate wavelength through the back and forth reflections of different filters and mirrors, the light enters the corresponding port of the fiber array.
  • the purpose is to decompose most wavelengths in the multimode fiber into single wavelengths and output them from different wavelength channels to achieve method of optical switching. Because the optical switch module in the radar system needs low insertion loss, high return loss, high power withstand, polarization state >18dB, and high reliability, these key parameters DWDM can well meet the requirements.
  • the optical path switching method of the laser radar based on the DWDM optical switch module to measure the three-dimensional air volume the specific steps are:
  • v f D * ⁇ /2 (where f D is the Doppler frequency shift generated by the aerosol backscattering signal, ⁇ is the laser wavelength, and v is the wind speed in the light detection direction)
  • the telescope is divided into four parts, and shoots into the atmosphere at different angles simultaneously. According to the counterclockwise direction, take the upper right corner as the No. 1 telescope tube, and mark los1.los2.los3.los4 in turn; among them, the horizontal angle between los1, los3, los 2, and los 4 is 27°; los 1, los 2, los 3. The vertical angle between los 4 intervals is 15°, so that the emitted laser light can form a rectangular matrix, as shown in Figure 4.
  • ⁇ up arctan 2(-y u ,-x u )
  • ⁇ down arctan 2(-y d ,-x d )
  • the wind speed and wind direction state of the upper and lower beam planes are obtained, and then the wind shear index and turbulence state, as well as the wind speed state of the altitude layer are calculated.
  • STATUS(v los ) is the flag bit, ⁇ los : the wind speed label difference; Average wind speed; H lidar : radar installation height; X t : horizontal measurement distance; ⁇ s : vertical beam angle; H hub : hub height.

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Abstract

一种基于DWDM光开关模块（8）测量三维风量的光路切换通道，通道是通过可调谐种子源激光器（1）发出不同波段的激光，经过隔离分路、调制、放大，再通过DWDM光开关模块（8），进行分配到不同的对应的波长光路中的通道，其中还包括可调谐种子源激光器（1）输出不同波长是通过可调谐种子驱动（2）调整电流来实现的。同时还提供了包括光路切换通道的切换方法及激光雷达，是可调谐种子源和DWDM光开关取代原先MEMS光开关的新型方法，是能够通过采用DWDM光开关替换常规MEMS光开关，DWDM作为无源器件，无需外接供电，也不需要电路时序控制，插损较低，成本低，可靠性高，易于集成，可维护性高，满足目前批量生产激光雷达的需求。

Description

一种基于DWDM光开关模块测量三维风量的光路切换通道和切换方法、及激光雷达 技术领域
本发明属于三维风量测量设备及方法的技术领域，特别是涉及一种基于DWDM光开关模块测量三维风量光通道和切换方法、及激光雷达。
背景技术
相干多普勒激光雷达利用气溶胶后向散射信号和本振光的拍频信号，获取散射信号的多普勒频移，从而获得风速信息。而反演三维风场需要至少三个方向的风速值，通常激光雷达都会通过扫描方式来测量多个方向的风速。一般激光器环形器只有单个输出头，只能测量单个径向风速，无法辨别区域类的一个风速和风向的状态，我们需要在后面增加一个实现多通道切换的光学器件，从而实现多方向形成三维风量的测量方式。
现有的光切换的方法有：(1)机械式CDL结构，在望远镜筒的前方加装扫描器，扫描器的中心有一个8°的光楔元件，当光通过光楔时会发生折射，当扫描器旋转一周后，所扫到的一周形成倒立圆锥形，激光雷达在该扫描区域形成几个方向的坐标系，通过确认坐标系中的不同方向的风速，从而获得该风场风速信息。该方案，不过价格偏高，频率不宜过快，偏转角度控制比较繁琐，需要单独的控制器来控制扫描方式，可靠性一般；长期旋转对轴承的损耗比较大，导致光路中心容易有偏差，装入雷达使其整体结构偏大。
(2)磁光开光结构，在环形器的后面接入磁光开关，磁光开关是利用法拉第磁光效应的光开关，通过外加磁场的改变来改变磁光晶体对入射偏振光偏振面的作用，达到光路切换的效果，在通过不同指向的望远镜进行收发激光，从而实现三维风场的探测。该方案结构小巧，开关速度快，稳定性高，驱动电压低，串扰小，寿命时间长，但是价格比较高，需要额外信号控制时序，需要控温，来防止器件的插损变化，内部光学元件过多，器件参数的一致性难以控制，其制作周期较长，无法满足批量生产的需求。
(3)微机械式MEMS光开关，光通过透镜聚焦在mems振镜上，振镜通过电调谐，使其转动不同方向后，将光耦合的光纤阵列中，从而达到切换的光通道的效果，该方案价格便宜，内部光学元件少易集成，器件参数一致性比较好控制，制作周期短，能满足批量生产的需求，可调速率高，但是MEMS芯片属于半活动部件，偏转次数有寿命限制，和磁光开关比少了10^6，而且其内部光斑小，器件承受峰值功率高，耐受功率低。需要外部提供电路作为控制信号，且时序控制时容易出现漏切光或不切光的状态。
同时，现有使用MEMS光开关还存在以下的问题：
(a)现有方法使用MEMS光开关,耐受功率低，不利于现有激光雷达提升性能，容易被高功率打坏pigtail，导致插损变大，甚至不出光，器件直接损坏；且光纤阵列膜层无法承受过高功率，光纤通过C-LENS透镜聚焦在微振镜上，温度非常高，反射光直接将光纤阵列的膜层打坏；DWDM密集波分复用器为无源器件，对于功率可定制化，内部元器件可通过镀激光损伤膜层，防止元器件在雷达提升性能过程中出现被高功率激光击穿等相应问题而导致的插损变大，不出光等情况。DWDM密集波分复用器，可使用大模场无源光纤，以及内部镀膜的工艺，提高光功率输入以及输出，以便于激光雷达对未来的大能量的提升有很大帮助。
(b)现有方法使用MEMS光开关，对温度比较敏感，内部的C-LENS透镜折射率发生变化，在激光耦合到光纤阵列时容易偏，打到周边的胶水上导致气化，汽化胶水的会附着在光纤阵列上，光通过后容易导致端面烧毁；DWDM密集波分复用器由于内部结构简单，受温度影响低，无透镜耦合因素的影响
(c)现有方法使用MEMS光开关，需要电路板时序精确调制，否则容易出现漏切光，或者不出光的状态，造成雷达探测到错误数据，误码率高；DWDM密集波分复用器，属于无源器件，无需外部的电源以及信号控制，通过内部的滤波片和反射镜结构，筛检不同的波长，从不同波长的光纤输出，从而达到切换通道的效果。
基于上述的现有方法不足，为了满足目前测风激光雷达光开关模块低成本，高可靠性，能批量生产要求，急需新的技术方案。
发明内容
技术方案：为了解决上述的技术问题，本发明基于可调种子激光器+无源器件DWDM(其中DWDM又称为密集波分复用器)基础上，提出一种基于DWDM开关模块的新型光通道，以及光通道下的切换方法，进一步提出具有上述光通道结构的激光雷达。
基于DWDM开关模块的光通道，是通过可调种子激光器给出不同波段的激光，经过放大后通过DWDM后，可自动分配到所对应的波长光路中，后经过望远镜发射到大气中，同时接收到大气的回波信号，回波信号也从相应的通道接收，从而获得风速信息。
本发明提出了一种基于DWDM光开关模块测量三维风量的光路切换通道，具体内容为：该通道是通过可调谐种子源激光器发出不同波段的激光，经过隔离分路、调制、放大，再通过DWDM光开关模块，进行分配到不同的对应的波长光路中的通道，其中还包括可调谐种子源激光器输出不同波长是通过可调谐种子驱动调整电流来实现的。
同时，本发明还提出了包括上述光路切换通道的激光雷达，所述激光雷达采用权利要求1所述的光路切换通道，具体地包括可调谐种子源激光器、可调谐种子驱动隔离器、DWDM光开关模块、望远镜组、耦合器、光电探测器、A/D数据采集及信号处理模块；
所述可调谐种子驱动用于辅助可调谐种子源激光器发出不同波长的激光；所述可调谐种子源激光器用于发出不同波长的激光，发送至隔离器；
所述隔离器，将激光分为两路，一路激光经过DWDM光开关模块、望远镜组光路回传处理，与另一路激光在耦合器耦合、相干；
所述光电探测器，用于对耦合后光信号转化为电信号，输出差频信号；
所述A/D数据采集及信号处理模块，连接在光电探测器输出信号端，进行数据处理，获得信号的时域及频域图。
作为改进，还包括声光调制器、射频驱动器、激光放大模块；所述视频驱动器用于将外部信号输出至声光调制器；所述声光调制器设置在隔离器输出信号端，用于对激光进行调制处理；所述激光放大模块在声光调制器输出信号端，用于对调制器输出光放大至合适功率。
作为改进，还包括光纤环形器，包括多个端口，一个端口用于接收激光放大模块的光射光，第二个端口用于发射信号光，第三个端口用于接收依次经过DWDM光开关模块、望远镜组回传处理的回波信号光。
同时，本发明还提供了所述基于DWDM光开关模块测量三维风量的激光雷达的光路切换方法，具体步骤为：
(i)通过可调谐种子驱动调整种子源电流，来调谐种子源激光器发出不同波段的激光；
(ii)通过分束器将(i)中激光分为两路，一路是激光经过可调衰减器后作为本振光输入到耦合器；另一路是激光经过声光调制器后被调制成脉冲激光并产生移频量f AOM， 脉冲激光经激光放大模块放大后，经过光纤环形器、DWDM光开关模块和望远镜组发射到大气中，脉冲激光与大气中运动的气溶胶粒子相互作用，气溶胶的后向散射信号产生多普勒频移f D，然后再返回DWDM光开关模块、光纤环形器，直至耦合器与本振光相干拍频；相干拍频后的信号又经过平衡光电探测器转换成模拟射频信号，用A/D数据采集及信号处理模块将模拟信号转换成数字信号，然后通过算法处理计算出信号的频率f＝f AOM+f D，f D为气溶胶后向散射信号产生的多普勒移频量。
作为改进，DWDM光开关模块将光路分为多通道，当建立坐标系，定义当f-f 0>0时，径向风速应大于0，其中径向风速
Figure PCTCN2021113434-appb-000001
f：接收到的散射信号的总频率；f AOM：声光移频频率，其中建立坐标系的具体方法：将望远镜分为四份，同时以不同角度射向大气中，按照逆时针方向，以右上角为1号望远镜筒，进行顺序标注，依次标注los1、los2、los3、los4；其中los1、los3、los2、los4间隔的水平夹角为30°；los 1、los 2，los 3、los 4间隔的垂直夹角为25°，这样打出去的激光构成一个矩形方阵，以los1与los2射出的光束n1和n2在测试距离范围平面上，形成一条水平线，以此水平线为上光束平面；以los3与los4射出的光束n3和n4在测试距离范围平面上，形成一条水平线，以此水平线为下光束平面。
作为改进，根据几何关系，上光束平面中，两束激光
Figure PCTCN2021113434-appb-000002
视线方向风速分别为：
Figure PCTCN2021113434-appb-000003
则x u、y u的解为：
Figure PCTCN2021113434-appb-000004
上光束平面风速、风向分别为：
Figure PCTCN2021113434-appb-000005
θ up＝arctan 2(-y u,-x u)。
作为改进，计算下波束平面风速分量v down，在下光束平面中，根据几何关系，两束 激光
Figure PCTCN2021113434-appb-000006
视线方向风速分别为：
Figure PCTCN2021113434-appb-000007
则x d、y d的解为：
Figure PCTCN2021113434-appb-000008
其中，下光束平面风速、风向分别为：
Figure PCTCN2021113434-appb-000009
θ down＝arctan 2(-y d,-x d)
其中η:激光器效率常数，θt：水平望远镜发射夹角，θup：上平光束夹角，Vup：上平面风速，Vdown:下平面风速，θdown：下平面光束夹角。
作为改进，其中进行计算出风切变的指数和湍流状态，以及不同高度层的风速状态如下：
(i)湍流状态
Figure PCTCN2021113434-appb-000010
Figure PCTCN2021113434-appb-000011
(ii)风切变指数
Figure PCTCN2021113434-appb-000012
(iii)不同高度层的风速计算
Figure PCTCN2021113434-appb-000013
Figure PCTCN2021113434-appb-000014
其中STATUS(v los)：为标志位，σ los：风速标注差；
Figure PCTCN2021113434-appb-000015
风速平均值；H lidar：雷达安装高度；X t：水平测量距离；θ s：垂直光束角度；H hub：轮毂高度。
有益效果：本发明提出技术内容是利用可调谐种子源和DWDM密集波分复用器取代原先激光雷达利用光开关的方法，是一种新型的光通道切换方法，具体是通过可调种子激光器给出不同波段的激光，经过放大后通过DWDM光开关模块后，可自动分配到所对应的波长光路中，后经过望远镜发射到大气中，同时接收到大气的回波信号，回波信号也从相应的通道接收，从而获得风速信息。
进一步地与现有的常规相比，具有如下的优势：采用DWDM光开关替换了常规的MEMS光开关，DWDM作为无源器件，无需外接供电，也不需要电路时序控制，插损较低，成本低，可靠性高，易于集成，可维护性高，满足目前批量生产激光雷达的需求。同时，无需外部电信号控制，无需外加控温系统，可集成于小型化，可输出多路，插损小，可按需求定制换大能量器件，对雷达提升性能有着极大的帮助。
其中，插损是指插入损耗，由光纤输出头的进入光功率比输出光功率的比值，具体表示为：
Figure PCTCN2021113434-appb-000016
附图说明
图1为本发明的激光雷达结构示意图。
图2为本发明DWDM波分复用器的组成结构示意图。
图3为本发明可调谐种子源激光器的工作原理图。
图4为本发明激光雷达四光束的集合关系图。
具体实施方式
下面结合实施例，对本发明的具体实施方式作进一步详细描述。以下实施例用于说明本发明，但不用来限制本发明的范围。
见图1中，本发明的基于DWDM光开关模块测量三维风量的激光雷达具体的结构为：
可调谐种子源激光器1：用于输出不同波长的连续激光。
可调谐种子驱动2：用于调制种子源激光器1不同波长。
隔离器3：防止回光返回可调谐激光器1，保护可调谐种子源激光器1不受损伤；并且将可调谐种子源激光分为本振光和信号光两路。
声光调制器4：由隔离器3输出的连续光，经过声光调制器4后，进行脉冲调制形成脉冲激光，且频率发生相应变化移动(频率移频量取决于使用的声光调制器4的频率)。
射频驱动器5：将外部信号输出给声光调制器4进行调制工作。
激光放大模块6：将调制器输出光放大至适合功率，以便探测。
光纤环形器7：共有三个端口，一端口接收放大模块发射的光，二端口发射信号光，三端口接收回波信号光。
DWDM密集波分复用器，也可称为DWDM光开关模块8：将不同波长的激光分别通过不同的通道输出到望远镜后，发射到大气中，并通过收发同置的方式来接收大气的激光回波信号。
望远镜组9：将能量汇聚在所需的大气距离，同时接收大气中激光后向散射的信号。
耦合器10：将隔离器2输出的本振光和光纤放大器5的环形器回波信号进行耦合，相干，并将相干后的激光分为两束输出至平衡探测器8中。
光电探测器11：将7耦合的两束相干光进行拍频，拍频后的光信号转换成电信号后，输出差频信号。
A/D数据采集及信号处理模块12：将平衡光电探测器8输出的连续的模拟信号转换成离散的数字信号，进行数据处理，并得到信号的时域及频域图。
作为本发明的具体实施方式，采用上述的激光雷达具体的测试方法为：
通过可调谐种子驱动2调整可调谐种子源激光器1的电流，来控制可调谐种子源变化不同的波长输出连续激光，激光通过隔离器3，也可以为分路器后，一路分至本振光作为拍频，一路在主光路上作为信号光，与此同时雷达电路板提供给射频驱动器5同步调制信号，在由射频驱动器5给声光调制器4调制信号，信号光经过声光调制器4，被调制成脉冲激光且产生相应与声光调制器4的频率的移频量f AOM。
光纤放大器6被放大至探测所需的功率大小；输出的脉冲放大激光从光纤环形器7一端口输入，从光纤环形器7的二端口输出，接入DWDM光开关模块8进行不同波长的通道切换后经过望远镜组8发射到大气中的气溶胶上，激光遇到气溶胶后，会有向后散射效果，此时通过望远镜组9接收后向散射信号，通过光纤环形器7；回光信号和分路/隔离器3的一路本振光耦合至耦合器10中，进行相干拍频并分为两束；两束相干拍频后的光信号输入光电探测器11，由光电探测器11将光信号转换为电信号，输入到A/D数据采集及信号处理模块12。
可调谐种子驱动2调整可调谐种子源激光器1发出不同波长激光是通过如下的设置：激光器在谐振腔的两端分别有一个取样光栅作为反射光栅。将两取样光栅的光栅间隔设计得略微有些不同。这样产生的光谱会有不同模式的间隔。只有同时处于两个光纤反射峰值上的模式，才有可能形成光的谐振放大。通过改变注入电流来移动其中的一个光栅的反射谱，这样便可以使反射峰重合位置发生变化，从而得到不同频率的输出光。同样，中间有一级相位区，也是作为精细调节区，通过此区改变各模式振荡位置来实现准连续的波长调节，范围可达百纳米，且选择波长更为精细。
可选择地，通过增加电流调制出几个不同波长，由引一路光出来进入标准具，通过功率变化-电流变化-电压变化，来实现稳波长，主要原因在于风速反演中，风速大小和波长相关，波长精度会影响风速精度。
DWDM光开关模块8，又称为DWDM密集波分复用器的工作原理：类似于多个WDM器件集成在一起。多个波长通过多模光纤经过DWDM波分复用器后，通过波分复用器将不同的波长的激光分离开来。根据DBR可调谐种子源激光器调制出的几个波长合波激光通过光纤耦合至DWDM光器件中，光通过棱镜折射到每一个光纤阵列中，每个光纤阵列的前端放置介质膜的滤波片，只有光波长在该滤波范围内，才可通过滤波片进入光纤中发射出去；否则无法通过该波长的滤波片，会被该滤波片反射回去，此时，在模块的边缘镀了一层反射膜，将第一个滤波片反射回来的光再次反射到下一个光纤阵列的端口，同样下一个端口放置着不同波长的滤波片。依次反复作用，通过不同的滤波片和反射镜的来回反射找到合适波长后，光进入该光纤阵列对应端口，目的是将多模光纤中的多数波长分解为单一波长从不同的波长通道输出，实现光切换的方法。由于雷达系统里光开关模块需要低插损，高回损，耐受功率高，偏振态>18dB，可靠性高,这些关键参数DWDM都 可以很好的满足要求。
实施例1
基于DWDM光开关模块测量三维风量的激光雷达的光路切换方法，具体步骤为：
(i)通过可调谐种子驱动2调整种子源电流，来调谐种子源激光器1发出不同波段的激光；
(ii)通过分束器将(i)中激光分为两路，一路是激光经过可调衰减器后作为本振光输入到耦合器10；另一路是激光经过声光调制器4后被调制成脉冲激光并产生移频量f AOM，脉冲激光经激光放大模块6放大后，经过光纤环形器7、DWDM光开关模块8和望远镜组9发射到大气中，脉冲激光与大气中运动的气溶胶粒子相互作用，气溶胶的后向散射信号产生多普勒频移f D，然后再返回DWDM光开关模块8、光纤环形器7，直至耦合器10与本振光相干拍频；相干拍频后的信号又经过平衡光电探测器11转换成模拟射频信号，用A/D数据采集及信号处理模块12将模拟信号转换成数字信号，然后通过算法处理计算出信号的频率f＝f AOM+f D，f D为气溶胶后向散射信号产生的多普勒移频量。
因为已知f AOM，通过公式v＝f D*λ/2(其中f D为气溶胶后向散射信号产生的多普勒移频量，λ为激光波长，v为光探测方向上的风速)和脉冲激光飞行时间ΔT计算出不同距离D＝(ΔT*c)/2的风速(c＝3*10 8m/s，为光速)。由于激光雷达测量的是一个风场的风速变化信息，而单一通道只能探测到激光雷达的径向风速，无法测风向，及变化的状态；如图1，光开将光路分为多通道可实现反演三维风场的风向，风速以及变化的状态。
(1)测量径向风速v 1、v 2、v 3、v 4，其计算公式为：
Figure PCTCN2021113434-appb-000017
根据前面坐标系定义，当f-f 0>0时，径向风速应大于0，因此，对于得到的径向风速，实际应用时，v＝-v，其中f：接收到的散射信号的总频率；f AOM：声光移频频率。
本发明中将望远镜分为四份，同时以不同角度射向大气中。按照逆时针方向，以右上角为1号望远镜筒，依次标注los1.los2.los3.los4；其中los1、los3，los 2、los 4间隔的水平夹角为27°；los 1、los 2，los 3、los 4间隔的垂直夹角为15°，这样打出去的激光可构成一个矩形方阵，如图4。我们以los1与los2射出的光束n1和n2在测试距离 范围平面上，形成一条水平线，以此水平线为上光束平面；我们以los3与los4射出的光束n3和n4在测试距离范围平面上，形成一条水平线，以此水平线为下光束平面。
(2)计算上光束平面风速分量v up。
在上光束平面中，根据几何关系，两束激光
Figure PCTCN2021113434-appb-000018
视线方向风速分别为：
Figure PCTCN2021113434-appb-000019
则x u、y u的解为：
Figure PCTCN2021113434-appb-000020
因此，上光束平面风速、风向分别为：
Figure PCTCN2021113434-appb-000021
θ up＝arctan 2(-y u,-x u)
(3)计算下波束平面风速分量v down。
在下光束平面中，根据几何关系，两束激光
Figure PCTCN2021113434-appb-000022
视线方向风速分别为：
Figure PCTCN2021113434-appb-000023
则x d、y d的解为：
Figure PCTCN2021113434-appb-000024
因此，下光束平面风速、风向分别为：
Figure PCTCN2021113434-appb-000025
θ down＝arctan 2(-y d,-x d)
此时获得上下光束平面的风速、风向状态，再计算出风切变的指数和湍流状态，以 及高度层的风速状态。
(4)湍流状态
Figure PCTCN2021113434-appb-000026
Figure PCTCN2021113434-appb-000027
(6)风切变指数
Figure PCTCN2021113434-appb-000028
(7)不同高度层的风速计算
Figure PCTCN2021113434-appb-000029
Figure PCTCN2021113434-appb-000030
其中STATUS(v los)：为标志位，σ los：风速标注差；
Figure PCTCN2021113434-appb-000031
风速平均值；H lidar：雷达安装高度；X t：水平测量距离；θ s：垂直光束角度；H hub：轮毂高度。
以上所述实施例仅表达了本发明的几种实施方式，其描述较为具体和详细，但并不能因此而理解为对发明专利范围的限制。应当指出的是，对于本领域的普通技术人员来说，在不脱离本发明构思的前提下，还可以做出若干变形和改进，这些都属于本发明的保护范围。因此，本发明专利的保护范围应以所附权利要求为准。

Claims (9)

  1. 一种基于DWDM光开关模块测量三维风量的光路切换通道，其特征在于：该通道是通过可调谐种子源激光器(1)发出不同波段的激光，经过隔离分路、调制、放大，再通过DWDM光开关模块(8)，进行分配到不同的对应的波长光路中的通道，其中还包括可调谐种子源激光器(1)输出不同波长是通过可调谐种子驱动(2)调整电流来实现的。
  2. 一种基于DWDM光开关模块测量三维风量的激光雷达，其特征在于：所述激光雷达采用权利要求1所述的光路切换通道，具体地包括可调谐种子源激光器(1)、可调谐种子驱动(2)、隔离器(3)、DWDM光开关模块(8)、望远镜组(9)、耦合器(10)、光电探测器(11)、A/D数据采集及信号处理模块(12)；
    所述可调谐种子驱动(2)用于辅助可调谐种子源激光器(1)发出不同波长的激光；
    所述可调谐种子源激光器(1)用于发出不同波长的激光，发送至隔离器(3)；
    所述隔离器(3)，将激光分为两路，一路激光经过DWDM光开关模块(8)、望远镜组(9)光路回传处理，与另一路激光在耦合器(10)耦合、相干；
    所述光电探测器(11)，用于对耦合后光信号转化为电信号，输出差频信号；
    所述A/D数据采集及信号处理模块(12)，连接在光电探测器输出信号端，进行数据处理，获得信号的时域及频域图。
  3. 根据权利要求2所述基于DWDM光开关模块测量三维风量的激光雷达，其特征在于：还包括声光调制器(4)、射频驱动器(5)、激光放大模块(6)；所述视频驱动器(5)用于将外部信号输出至声光调制器(4)；所述声光调制器(4)设置在隔离器(3)输出信号端，用于对激光进行调制处理；所述激光放大模块(6)在声光调制器(4)输出信号端，用于对调制器输出光放大至合适功率。
  4. 根据权利要求3所述基于DWDM光开关模块测量三维风量的激光雷达，其特征在于：还包括光纤环形器(7)，包括多个端口，一个端口用于接收激光放大模块(6)的光射光，第二个端口用于发射信号光，第三个端口用于接收依次经过DWDM光开关模块(8)、望远镜组(9)回传处理的回波信号光。
  5. 一种根据权利要求2-4任一所述基于DWDM光开关模块测量三维风量的激光雷达的光路切换方法，其特征在于：具体步骤为：
    (i)通过可调谐种子驱动(2)调整种子源电流，来调谐种子源激光器(1)发出不同波段的激光；
    (ii)通过分束器将(i)中激光分为两路，一路是激光经过可调衰减器后作为本振光输入到耦合器(10)；另一路是激光经过声光调制器(4)后被调制成脉冲激光并产生移频量f AOM，脉冲激光经激光放大模块(6)放大后，经过光纤环形器(7)、DWDM光开关模块(8)和望远镜组(9)发射到大气中，脉冲激光与大气中运动的气溶胶粒子相互作用，气溶胶的后向散射信号产生多普勒频移f D，然后再返回DWDM光开关模块(8)、光纤环形器(7)，直至耦合器(10)与本振光相干拍频；相干拍频后的信号又经过平衡光电探测器(11)转换成模拟射频信号，用A/D数据采集及信号处理模块(12)将模拟信号转换成数字信号，然后通过算法处理计算出信号的频率f＝f AOM+f D，f D为气溶胶后向散射信号产生的多普勒移频量。
  6. 根据权利要求5所述基于DWDM光开关模块测量三维风量的激光雷达的光路切换方法，其特征在于：DWDM光开关模块(8)将光路分为多通道，当建立坐标系，定义当f-f 0>0时，径向风速应大于0，其中径向风速
    Figure PCTCN2021113434-appb-100001
    f：接收到的散射信号的总频率；f AOM：声光移频频率，其中建立坐标系的具体方法：将望远镜分为四份，同时以不同角度射向大气中，按照逆时针方向，以右上角为1号望远镜筒，进行顺序标注，依次标注los1、los2、los3、los4；其中los1、los3、los2、los4间隔的水平夹角为30°；los 1、los 2，los 3、los 4间隔的垂直夹角为25°，这样打出去的激光构成一个矩形方阵，以los1与los2射出的光束n1和n2在测试距离范围平面上，形成一条水平线，以此水平线为上光束平面；以los3与los4射出的光束n3和n4在测试距离范围平面上，形成一条水平线，以此水平线为下光束平面。
  7. 根据权利要求6所述基于DWDM光开关模块测量三维风量的激光雷达的光路切换方法，其特征在于：
    根据几何关系，上光束平面中，两束激光
    Figure PCTCN2021113434-appb-100002
    视线方向风速分别为：
    Figure PCTCN2021113434-appb-100003
    则x u、y u的解为：
    Figure PCTCN2021113434-appb-100004
    上光束平面风速、风向分别为：
    Figure PCTCN2021113434-appb-100005
    θ up＝arctan2(-y u,-x u)。
  8. 根据权利要求6所述基于DWDM光开关模块测量三维风量的激光雷达的光路切换方法，其特征在于：计算下波束平面风速分量v down，在下光束平面中，根据几何关系，两束激光
    Figure PCTCN2021113434-appb-100006
    视线方向风速分别为：
    Figure PCTCN2021113434-appb-100007
    则x d、y d的解为：
    Figure PCTCN2021113434-appb-100008
    其中，下光束平面风速、风向分别为：
    Figure PCTCN2021113434-appb-100009
    θ down＝arctan2(-y d,-x d)，
    其中η:激光器效率常数，θt：水平望远镜发射夹角，θup：上平光束夹角，Vup：上平面风速，Vdown:下平面风速，θdown：下平面光束夹角。
  9. 根据权利要求5所述基于DWDM光开关模块测量三维风量的光路切换方法，其特征在于：其中进行计算出风切变的指数和湍流状态，以及不同高度层的风速状态如下：
    (i)湍流状态
    Figure PCTCN2021113434-appb-100010
    Figure PCTCN2021113434-appb-100011
    (ii)风切变指数
    Figure PCTCN2021113434-appb-100012
    (iii)不同高度层的风速计算
    Figure PCTCN2021113434-appb-100013
    Figure PCTCN2021113434-appb-100014
    其中STATUS(v los)：为标志位，σ los：风速标注差；
    Figure PCTCN2021113434-appb-100015
    风速平均值；H lidar：雷达安装高度；X t：水平测量距离；θs：垂直光束角度；H hub：轮毂高度。
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CN116879869A (zh) * 2023-09-06 2023-10-13 青岛镭测创芯科技有限公司 一种激光雷达控制方法、装置、电子设备及介质
CN116879869B (zh) * 2023-09-06 2024-01-19 青岛镭测创芯科技有限公司 一种激光雷达控制方法、装置、电子设备及介质
CN117214918A (zh) * 2023-11-09 2023-12-12 中国科学技术大学 一种瑞利多普勒测温测风激光雷达
CN117214918B (zh) * 2023-11-09 2024-03-29 中国科学技术大学 一种瑞利多普勒测温测风激光雷达
CN117728892A (zh) * 2024-02-07 2024-03-19 深圳市光为光通信科技有限公司 1.6t lpo或cpo光模块的光信号弹性自适应处理方法
CN117728892B (zh) * 2024-02-07 2024-04-26 深圳市光为光通信科技有限公司 1.6t lpo或cpo光模块的光信号弹性自适应处理方法

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