WO2022099838A1 - 一种相干接收装置及测风激光雷达系统 - Google Patents

一种相干接收装置及测风激光雷达系统 Download PDF

Info

Publication number
WO2022099838A1
WO2022099838A1 PCT/CN2020/135327 CN2020135327W WO2022099838A1 WO 2022099838 A1 WO2022099838 A1 WO 2022099838A1 CN 2020135327 W CN2020135327 W CN 2020135327W WO 2022099838 A1 WO2022099838 A1 WO 2022099838A1
Authority
WO
WIPO (PCT)
Prior art keywords
light
signal
signal light
mixer
local oscillator
Prior art date
Application number
PCT/CN2020/135327
Other languages
English (en)
French (fr)
Inventor
石川
张博
陈宏刚
梁雪瑞
成璇璇
Original Assignee
武汉光迅科技股份有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 武汉光迅科技股份有限公司 filed Critical 武汉光迅科技股份有限公司
Priority to US18/252,355 priority Critical patent/US20240007194A1/en
Priority to EP20961392.6A priority patent/EP4246835A4/en
Publication of WO2022099838A1 publication Critical patent/WO2022099838A1/zh

Links

Images

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/60—Receivers
    • H04B10/61—Coherent receivers
    • H04B10/614—Coherent receivers comprising one or more polarization beam splitters, e.g. polarization multiplexed [PolMux] X-PSK coherent receivers, polarization diversity heterodyne coherent receivers
    • 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
    • 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
    • G01S7/481—Constructional features, e.g. arrangements of optical elements
    • G01S7/4818—Constructional features, e.g. arrangements of optical elements using optical fibres
    • 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
    • G01S7/491—Details of non-pulse systems
    • G01S7/4912—Receivers
    • G01S7/4917—Receivers superposing optical signals in a photodetector, e.g. optical heterodyne detection
    • 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
    • G01S7/499—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00 using polarisation effects
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/60—Receivers
    • H04B10/61—Coherent receivers
    • H04B10/615—Arrangements affecting the optical part of the receiver
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/60—Receivers
    • H04B10/61—Coherent receivers
    • H04B10/616—Details of the electronic signal processing in coherent optical receivers
    • 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 present application relates to the technical field of optical communication, and in particular, to a coherent receiving device and a wind-measuring lidar system.
  • Wind Doppler lidar is a high-precision, high-resolution atmospheric wind field detection technology. It is widely used in atmospheric dynamics research, weather forecasting and atmospheric environment monitoring.
  • Traditional Doppler frequency shift detection The methods include edge detection technology and stripe imaging technology.
  • the Doppler frequency is determined by converting the frequency change of the signal into the relative energy change by mainly using the annular fringe or linear stripe interference pattern produced by Fabry-Perot resonator, Mach-Zehnder interferometer, Fizeau interferometer, etc. shift.
  • This frequency shift detection method generally requires a surface charge-coupled device (CCD) to receive the interference pattern.
  • the surface CCD is large in size, and the energy of the echo signal received by this method is usually weak.
  • the detected energy is also weak, because the energy will be affected by the system noise, which will cause certain errors in the detection of Doppler frequency shift.
  • the embodiments of the present application provide a coherent receiving device and a wind-measuring lidar system to solve at least one problem existing in the prior art.
  • an embodiment of the present application provides a coherent receiving device, the device includes: a polarization-maintaining fiber pin, a polarization beam splitter prism, a frequency mixer, a photodiode PD array, and a signal processing circuit; wherein,
  • the polarization-maintaining fiber pin is used for receiving local oscillator light and outputting the local oscillator light to the mixer, and the polarization state of the local oscillator light remains unchanged when transmitted in the polarization-maintaining fiber pin. Change;
  • the polarization beam splitting prism is used for receiving signal light, dividing the signal light into a first signal light with p polarization state and a second signal light with s polarization state, and separating the first signal light and the The second signal light is output to the mixer;
  • the mixer configured to mix the first signal light and the second signal light with the local oscillator light respectively, and output the mixed light to the PD array;
  • the PD array is used to perform photoelectric conversion on the mixed light to obtain a differential current signal
  • the signal processing circuit is used to convert the differential current signal to obtain a differential voltage signal; the derivation formula of the differential voltage signal includes the part of the frequency difference between the signal light and the local oscillator light, and detects the The frequency of the differential voltage signal is used to obtain the value of the frequency difference between the signal light and the local oscillator light; according to the value of the frequency difference between the signal light and the local oscillator light, the Doppler frequency of the signal light is obtained. shift.
  • the signal processing circuit includes: an amplifier module, an analog-to-digital converter, and a processor; wherein,
  • the amplifier module for amplifying the differential current signal and converting the differential current signal into a differential voltage signal
  • the analog-to-digital converter is configured to perform analog-to-digital converter ADC sampling on the differential voltage signal to obtain an ADC sampling signal;
  • the processor is configured to process the ADC sampling signal to obtain the frequency of the ADC sampling signal, where the frequency of the ADC sampling signal is the Doppler frequency shift amount of the signal light.
  • the derivation formula of the differential voltage signal is: and Wherein, R is the responsivity of the photodiode in the PD array, G is the cross-group gain of the amplifier module, P in is the light intensity of the signal light, P lo is the light intensity of the local oscillator, ⁇ in is the angular frequency of the signal light, ⁇ lo is the angular frequency of the local oscillator light; ⁇ in is the initial phase of the signal light, ⁇ lo is the initial phase of the local oscillator light, and ⁇ is the angle between the first signal light and the second signal light and the horizontal direction;
  • the value of the term ( ⁇ in - ⁇ lo ) ⁇ t in the derivation formula of the differential voltage signal is the Doppler frequency shift amount of the signal light.
  • the amplifier module adopts a low-bandwidth amplifier, which is further configured to implement high-frequency filtering of the differential current signal.
  • the apparatus further includes: a low-frequency filter circuit disposed between the PD array and the amplifier module; wherein,
  • the low-frequency filter circuit is used to control the cut-off frequency of the differential current signal, so as to realize low-frequency filtering of the differential current signal.
  • the signal light is generated based on the following manner: the laser light emitted by the laser enters the atmosphere and interacts with aerosol molecules in the atmosphere to generate an echo signal, the echo signal being the the signal light.
  • the local oscillator light is the laser light emitted by the laser into the polarization-maintaining fiber ferrule.
  • the mixer includes a first sub-mixer and a second sub-mixer; wherein,
  • the first sub-mixer configured to mix the first signal light and the local oscillator light
  • the second sub-mixer is used for mixing the second signal light and the local oscillator light.
  • the device further comprises: a reflecting prism and a lens array disposed between the mixer and the PD array; wherein,
  • the mixed light output by the mixer is reflected by the reflecting prism and collected by the lens array, and then output to the PD array.
  • the device further includes: two C-lenses disposed between the polarization beam splitter prism and the mixer; wherein,
  • the first signal light and the second signal light output from the polarization beam splitting prism are respectively condensed into the frequency mixer through the two C lenses.
  • an embodiment of the present application provides a wind measurement lidar system, including: the coherent receiving device, a laser unit, and a telephoto system as described in the first aspect; wherein,
  • the laser unit is used for emitting laser light, dividing the laser light into a first part of the laser light and a second part of the laser light; outputting the first part of the laser light to the telephoto system, and outputting the second part of the laser light to the the coherent receiving device;
  • the telephoto system is used for injecting the first part of the laser light into the atmosphere, receiving echo signals that interact with aerosol molecules in the atmosphere, and outputting the echo signals to the coherent receiving device;
  • the coherent receiving device is configured to receive the second part of the laser light as the local oscillator light, interfere the local oscillator light with the echo signal to form a demodulated signal, and obtain the echo signal through the demodulated signal.
  • the Doppler frequency shift amount of the wave signal, and the wind speed is determined according to the Doppler frequency shift amount.
  • the laser unit includes: a laser and a beam splitter; wherein,
  • the laser for emitting laser light
  • the beam splitter is used for dividing the laser light into a first part of laser light with a first energy and a second part of laser light with a second energy, where the first energy is smaller than the second energy.
  • the embodiment of the present application discloses a coherent receiving device and a wind-measuring lidar system.
  • the device includes: a polarization-maintaining fiber pin, a polarization beam splitter prism, a frequency mixer, a photodiode PD array, and a signal processing circuit;
  • the polarization-maintaining fiber ferrule is used to receive the local oscillator light and output the local oscillator light to the mixer, and the polarization state of the local oscillator light remains unchanged during transmission in the polarization-maintaining fiber ferrule
  • the polarization beam splitter prism is used to receive signal light, divide the signal light into a first signal light with p polarization state and a second signal light with s polarization state, and separate the first signal light and all
  • the second signal light is output to the mixer;
  • the mixer is configured to mix the first signal light and the second signal light with the local oscillator light respectively, and mix the frequencies
  • the coherent receiving device in the embodiment of the present application uses the interference of the local oscillator light and the signal light to perform Doppler frequency detection, and adopts the differential signal output method, which can eliminate common mode noise, improve the detection accuracy, and the Doppler frequency shift detection is not affected by the Due to the influence of laser wavelength drift, the coherent receiving device adopts a dual-polarization detection scheme, so that even if the polarization direction of the signal light changes, the Doppler frequency shift of the signal light can be effectively detected.
  • FIG. 1 is a schematic structural diagram of a coherent receiving apparatus according to an embodiment of the present application
  • FIG. 2 is a schematic diagram of a steering structure between a mixer and a PD array provided by an embodiment of the present application;
  • FIG. 3 is a schematic structural diagram of another coherent receiving apparatus provided by an embodiment of the present application.
  • FIG. 4 is a schematic diagram of a connection structure between a PD array and an amplifier module provided by an embodiment of the present application;
  • FIG. 5 is a schematic structural diagram of a wind measurement lidar system provided by an embodiment of the present application.
  • Fig. 6 is a graph of atmospheric transmission window and human eye damage threshold
  • FIG. 7 is a schematic diagram of a circuit structure of a coherent receiving apparatus provided by an embodiment of the present application.
  • FIG. 8 is a schematic structural diagram of a 90-degree mixer provided by an embodiment of the present application.
  • FIG. 9 is a schematic diagram of a port phase difference of a 3dB coupler according to an embodiment of the present application.
  • spatially relational terms such as “under”, “under”, “under”, “under”, “over”, “above”, etc., are used herein may be used for convenience of description to describe the relationship of one element or feature to other elements or features shown in the figures. It should be understood that the spatially relative terms are intended to encompass different orientations of the device in use and operation in addition to the orientation shown in the figures. For example, if the device in the figures is turned over, then elements or features described as “below” or “beneath” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the exemplary terms “below” and “under” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatial descriptors used herein interpreted accordingly.
  • FIG. 1 is a schematic structural diagram of a coherent receiving device provided by an embodiment of the present application.
  • the coherent receiving device includes: a polarization-maintaining fiber pin 110 , a polarization beam splitter prism 120 , a mixer 130 , an optoelectronic Diode (Photo-Diode, PD) array 140 and signal processing circuit 150; wherein,
  • the polarization-maintaining fiber pin 110 is used to receive the local oscillator light and output the local oscillator light to the mixer 130 , and the local oscillator light is polarized during transmission in the polarization-maintaining fiber pin 110 state remains unchanged;
  • the polarization beam splitter prism 120 is used for receiving signal light, dividing the signal light into a first signal light with p polarization state and a second signal light with s polarization state, and separating the first signal light and all outputting the second signal light to the mixer 130;
  • the mixer 130 is configured to mix the first signal light and the second signal light with the local oscillator light respectively, and output the mixed light to the PD array 140;
  • the PD array 140 is used for photoelectric conversion of the mixed light to obtain a differential current signal
  • the signal processing circuit 150 is configured to convert the differential current signal to obtain a differential voltage signal; the derivation formula of the differential voltage signal includes the part of the frequency difference between the signal light and the local oscillator light, and detects The frequency of the differential voltage signal to obtain the value of the frequency difference between the signal light and the local oscillator light; according to the value of the frequency difference between the signal light and the local oscillator light, the Doppler of the signal light is obtained Frequency shift amount.
  • the coherent receiving device has two input lights: one is signal light, and the other is local oscillator light.
  • the signal light and the local oscillator light are both laser light generated by the same laser, and the signal light is generated based on the following method: the laser light emitted by the laser enters the atmosphere and interacts with aerosol molecules in the atmosphere to generate echo signals , the echo signal is the signal light.
  • the local oscillator light is the laser light emitted by the laser into the polarization-maintaining fiber pin 110 .
  • the signal light is the echo signal that interacts with the aerosol molecules in the atmosphere, and its polarization state is uncertain; the local oscillator light is polarized light.
  • the local oscillator light is introduced into the coherent receiving device, which can improve the sensitivity of Doppler frequency shift detection, and eliminate the frequency drift caused by the laser working for a long time or the change of the external environment.
  • the coherent receiving apparatus further includes: two C-lenses 160 disposed between the polarization beam splitter prism 120 and the mixer 130 ; wherein the polarization beam splitter prism 120 outputs The first signal light and the second signal light are condensed into the mixer 130 through the two C-lenses 160 respectively.
  • the two C lenses 160 and the mixer 130 are directly bonded together, and the two C lenses 160 are used to detect the first signal light input to the mixer 130 . and the second signal light is converged.
  • Relative displacement will occur (that is, the position of the two C lenses 160 and the mixer 130 will change together), that is, the setting scheme in which the two C lenses and the mixer are bonded together in the embodiment of the present application has more advantages.
  • Good stability and temperature characteristics the optical paths of the first signal light and the second signal light have a large tolerance to the position, and even if the two C lenses 160 and the mixer 130 change their positions together, the influence on the coupling efficiency is small. .
  • the coherent receiving device further includes: a substrate 170; wherein the polarizing beam splitting prism 120, the two C lenses 160, the frequency mixer 130 and the PD array 140 are arranged on on the substrate 170 .
  • the polarizing beam splitter prism 120 is composed of two prisms glued together, and a polarization beam splitter film is provided on the glued surfaces of the two prisms.
  • the polarization state is parallel to the input light and the method.
  • the first signal light (p polarization state) in the line plane continues to propagate forward through the polarization beam splitter film, and exits the polarization beam splitter prism 120; the polarization state is perpendicular to the input light and the second signal light (s polarization state) in the normal plane.
  • the reflection turning (90 degrees) occurs, and the polarization beam splitting prism 120 is reflected and turned (90 degrees) again on the inclined plane, so as to form the second signal light parallel to the first signal light, and emit the polarization beam splitter. beam prism 120 .
  • the mixer 130 includes one local oscillator port and two signal ports, the local oscillator port is connected to the polarization-maintaining fiber pin 110, and the two signal ports are respectively connected to the two signal ports.
  • C lens 160 is attached.
  • the polarization-maintaining fiber pin 110 and the local oscillator port of the mixer 130 can be bonded together by UV glue (Ultraviolet Rays); the two C-lenses 160 and the two signal ports of the mixer 130 can be coupled by UV glue glued together.
  • the first signal light and the second signal light are condensed through two C-lenses 160 respectively and enter the mixer 130, where the mixer 130 includes a first sub-mixer and a second sub-mixer wherein, the first sub-mixer is used to mix the first signal light and the local oscillator light; the second sub-mixer is used to mix the second signal light mixing with the local oscillator light.
  • the first sub-mixer and the second sub-mixer may be 90-degree mixers.
  • the two polarization states of the signal light (the first signal light and the second signal light) are respectively mixed with the local oscillator light in the corresponding 90-degree mixers, and then sent to the PD array 140 through the mixer 130.
  • the two C lenses 160 are disposed on the substrate 170 .
  • the signal processing circuit 150 includes: an amplifier module, an analog-to-digital converter, and a processor; wherein, the amplifier module is configured to amplify the differential current signal, and convert the differential current The signal is converted into a differential voltage signal; the analog-to-digital converter is used for sampling the differential voltage signal by an analog-to-digital converter (Analog to Digital Converter, ADC) to obtain an ADC sampling signal; the processor is used for The ADC sampling signal is processed to obtain the frequency of the ADC sampling signal, and the frequency of the ADC sampling signal is the Doppler frequency shift amount of the signal light.
  • the wind speed can be determined according to the Doppler frequency shift of the signal light.
  • the coherent receiving device adopts the differential signal output mode, which can eliminate the common mode noise of the system and improve the detection accuracy.
  • the signal processing circuit 150 may only include an amplifier module, and the signal processing circuit 150 outputs the differential voltage signal amplified and converted by the amplifier module to the tube through the tube case pins of the coherent receiving device. Outside the casing, the differential voltage signal is processed by the analog-to-digital converter and the processor outside the casing to obtain the Doppler frequency shift of the signal light.
  • a low-frequency filter circuit is further provided between the PD array 140 and the amplifier module, and the low-frequency filter circuit is used to control the cut-off frequency of the differential current signal, so as to realize the correction of the differential current signal. Low frequency filtering of the current signal.
  • the amplifier module may use a low-bandwidth amplifier, so that it may also be used to implement high-frequency filtering of the differential current signal.
  • the differential current signal is amplified by a low bandwidth amplifier, so that the 1/f noise in the circuit can be effectively reduced, and the signal-to-noise ratio can be improved.
  • the PD array 140 and the signal processing circuit 150 are electrically connected through gold wires, so that the differential current signal output by the PD array 140 can be sent to the signal processing circuit 150 through the gold wires.
  • FIG. 2 is a schematic diagram of a steering structure between a mixer and a PD array provided by an embodiment of the present application.
  • the coherent receiving apparatus further includes: disposed between the mixer 130 and the PD array.
  • the mixed light output by the mixer 130 is turned by 90 degrees through the reflective prism 180 , and the turned light signal is converged into the PD array 140 through the lens array 190 .
  • lens brackets 1100 are provided on both sides of the PD array 140, and the lens brackets 1100 are used to fix the lens array 190, so that the center of the light passing surface of the lens array 190 is aligned with the center of the photosensitive surface of the PD array 140.
  • the lens holder 1100 is disposed on the substrate 170 .
  • the coherent receiving device further includes: a collimator 1200; wherein, the collimator 1200 is used to collimate the signal light input to the coherent receiving device, and the collimated signal The light is output to the polarizing beam splitting prism 120 .
  • the collimator 1200 is also disposed on the substrate 170 .
  • the coherent receiving apparatus further includes: a case 1300 , wherein the substrate 170 and the signal processing circuit 150 are arranged in the case 1300 . It should be noted that the devices provided on the substrate 170 are also located in the package 1300 .
  • the coherent receiving device may also adopt a method of setting an optical window, and a collimator is arranged in the optical window, so as to input the collimated signal light and local oscillator light to the coherent receiving device inside the device.
  • FIG. 3 is a schematic structural diagram of another coherent receiving device provided by an embodiment of the present application. As shown in FIG. 3 , the coherent receiving device includes: an optical window 210 , a polarization beam splitter prism 220 , a mixer 230 , and a PD array 240 and signal processing circuit 250; wherein,
  • the light window 210 is used to receive the local oscillator light and the signal light, and output the local oscillator light to the mixer 230, and output the signal light to the polarization beam splitter prism 220;
  • the polarization beam splitter prism 220 is used for receiving signal light, dividing the signal light into a first signal light with p polarization state and a second signal light with s polarization state, and separating the first signal light and all outputting the second signal light to the mixer 230;
  • the mixer 230 is configured to mix the first signal light and the second signal light with the local oscillator light respectively, and output the mixed light to the PD array 240;
  • the PD array 240 is used to perform photoelectric conversion on the mixed light to obtain a differential current signal
  • the signal processing circuit 250 is configured to process the differential current signal to obtain the Doppler frequency shift of the signal light.
  • the coherent receiving apparatus further includes: two C-lenses 260 disposed between the polarization beam splitter prism 220 and the mixer 230; wherein the polarization beam splitter prism 220 outputs The first signal light and the second signal light are condensed into the mixer 240 through the two C-lenses 260 respectively.
  • the coherent receiving apparatus further includes: a C lens 270 disposed between the light window 210 and the mixer 230 ; wherein the local oscillator light output by the light window 210 It is converged into the mixer 240 through the C-lens 270 .
  • FIG. 4 is a schematic diagram of a connection structure between a PD array and an amplifier module according to an embodiment of the present application.
  • every two PD devices in the PD array are connected to a low bandwidth amplifier TIA, two PD devices are connected in series, and one end Connect to Vcc, one end is grounded, Vcc provides reverse bias voltage for PD devices.
  • the amplifier module is composed of a low-bandwidth amplifier TIA, a resistor R2 and a capacitor C2 connected in parallel with the low-bandwidth amplifier TIA. By adjusting the sizes of R2 and C2, the gain and bandwidth of the low-bandwidth amplifier TIA can be controlled, so that the low-bandwidth amplifier TIA can be controlled.
  • the size of the filtering of the bandwidth amplifier TIA There is a low-frequency filter circuit between the PD array and the low-bandwidth amplifier TIA.
  • the low-frequency filter circuit consists of a series-connected resistor R1 and a capacitor C1.
  • R1 and C1 By adjusting the sizes of R1 and C1, the cutoff frequency of the differential current signal output by the PD array can be controlled. , so that the DC optical signal entering the low-bandwidth amplifier TIA can be eliminated, so as to realize low-frequency filtering of the differential current signal.
  • the size of the cutoff frequency can be adjusted according to the actual bandwidth used by the coherent receiving apparatus.
  • FIG. 5 is a schematic structural diagram of a wind-measuring lidar system provided by an embodiment of the application.
  • the wind-measuring lidar system includes: a coherent receiving device 310 , a laser unit 320 and a telephoto system 330 ; ,
  • the laser unit 320 is used for emitting laser light, dividing the laser light into a first part of the laser light and a second part of the laser light; outputting the first part of the laser light to the telephoto system 330, and outputting the second part of the laser light to the coherent receiving device 310;
  • the telephoto system 330 is used to inject the first part of the laser light into the atmosphere, receive echo signals that interact with aerosol molecules in the atmosphere, and output the echo signals to the coherent receiving device 310;
  • the coherent receiving device 310 is configured to receive the second part of the laser light as the local oscillator light, interfere the local oscillator light with the echo signal to form a demodulated signal, and obtain the The Doppler frequency shift amount of the echo signal, and the wind speed is determined according to the Doppler frequency shift amount.
  • the laser unit 320 includes: a laser 321 and a beam splitter 322; wherein the laser 321 is used for emitting laser light; the beam splitter 322 is used for dividing the laser light into A first part of the laser light with a first energy and a second part of the laser light with a second energy, the first energy being less than the second energy.
  • the laser light generated by the laser 321 is split by the beam splitter 322 according to a certain ratio, for example, the beam is split according to a ratio of 9:1, and 90% of the laser light is output to the said laser as local oscillator light
  • 10% of the laser light is emitted into the atmosphere through the telescopic system 330, so that the laser light interacts with the aerosol molecules in the atmosphere to generate echo signals, and the telescopic system 330 receives the echo signals and converts the The echo signal is output to the coherent receiving device 310 as signal light.
  • the laser 321 can emit a single-polarized narrow linewidth light source. A laser with a light emission wavelength of 1.55um is preferred.
  • Figure 6 is a graph of the atmospheric transmission window and the damage threshold of the human eye
  • the abscissa in Figure 6 is the beam wavelength (um)
  • the MPE is the maximum exposure of the human eye
  • the point-shaped curve is the human eye's safety curve for the beam light intensity.
  • the curve shows that the 1.5-1.8um wavelength laser has a higher safety threshold for the human eye.
  • the maximum allowable exposure of the 1.55um wavelength laser is 10 times that of the 2.1um wavelength laser, which is 5 orders of magnitude higher than the 1.06um wavelength laser.
  • lasers with a wavelength of 1.55um are commonly used, and beam splitters and circulators with a wavelength of 1.55um are relatively common. Therefore, the wind measurement lidar system in the embodiment of this application selects a laser with a wavelength of 1.55um, which is compatible with the wavelength range of existing standard devices. , and has a higher safety threshold for the human eye.
  • the wind measurement lidar system further includes: a circulator 340 located between the laser unit 320 and the telephoto system 330 .
  • the beam splitter 322 divides the laser light into a first part of the laser light with the first energy and a second part of the laser light with the second energy, the first part of the laser light is output to the 1 port of the circulator 340, and the first part of the laser light is output.
  • a part of the laser light is output from the 2 port of the circulator 340 to the telescopic system 330, and the telescopic system 330 injects the first part of the laser light into the atmosphere, and the first part of the laser light interacts with the aerosol molecules in the atmosphere (such as elastic scattering),
  • the backscattered echo signal is received by the telephoto system 330 and output to the 2 port of the circulator 340 , and the echo signal is output to the coherent receiving device 310 from the 3 port of the circulator 340 .
  • the telescopic system 330 may be a laser collimation system, which can collimate the small mode field divergent light source in the circulator 340 into a large mode field parallel beam, thereby enabling longer distance transmission.
  • the laser emits laser light with a center wavelength of ⁇ into the atmosphere. Since the aerosol molecules suspended in the atmosphere and moving with the wind have a scattering effect on the laser light, it is assumed that the component of the wind speed V in the viewing direction of the telephoto system is V ⁇ cos( ⁇ ), then the backscattered light signal received by the wind lidar system will generate a Doppler frequency shift ⁇ f proportional to the radial velocity of the aerosol molecules, and the Doppler frequency shift ⁇ f The formula is as follows:
  • ⁇ represents the radial motion direction of aerosol molecules. Therefore, by determining the Doppler frequency shift of the backscattered light signal received by the wind-measuring lidar system, the radial wind speed of aerosol molecules can be obtained according to the Doppler frequency shift.
  • the mixer includes a first sub-mixer and a second sub-mixer, and the first sub-mixer and the second sub-mixer respectively convert two orthogonal polarization states of the signal light (the first signal light and the second sub-mixer).
  • the signal light is mixed with the local oscillator light to realize the frequency shift demodulation of the signal light.
  • the formulas are as follows:
  • P in is the light intensity of the signal light
  • P lo is the light intensity of the local oscillator
  • ⁇ in is the angular frequency of the signal light
  • ⁇ lo is the angular frequency of the local oscillator
  • ⁇ in is the initial phase of the signal light
  • ⁇ lo is the local oscillator light. initial phase.
  • FIG. 7 is a schematic diagram of a circuit structure of a coherent receiving device provided by an embodiment of the present application.
  • the signal light is divided into a first signal light with p polarization state and a second signal light with s polarization state through a polarization beam splitter Signal light, the polarization beam splitter outputs the first signal light and the second signal light to the first sub-mixer (90-degree mixer) and the second sub-mixer (90-degree mixer) respectively );
  • the local oscillator light is divided into two identical local oscillator lights by the beam splitter, which are respectively output to the first sub-mixer (90-degree mixer) and the second sub-mixer (90-degree mixer).
  • FIG. 6 the signal light is divided into a first signal light with p polarization state and a second signal light with s polarization state through a polarization beam splitter Signal light, the polarization beam splitter outputs the first signal light and the second signal light to the first sub-mixer (90-degree mixer) and
  • FIG. 8 is a schematic structural diagram of a 90-degree mixer provided by an embodiment of the present application.
  • a single 90-degree mixer includes four 3dB couplers and a 90-degree phase delayer.
  • a phase retarder is an additional waveguide with a length equal to one-quarter of the laser wavelength, capable of producing a 90-degree phase shift.
  • the local oscillator light is divided into two identical local oscillator lights by the beam splitter, and the light intensity of the local oscillator light entering a single 90-degree mixer is
  • FIG. 9 is a schematic diagram of a port phase difference of a 3dB coupler provided by an embodiment of the present application. As shown in FIG.
  • one port of the 3dB coupler outputs ⁇ +d ⁇ , and the other port outputs 0°.
  • the formula of the electric field output after the first signal light and the local oscillator light are mixed by the first sub-mixer is as follows:
  • the formula of the differential voltage output after the differential current output by the PD array is amplified and converted by the TIA is as follows:
  • the differential voltage signals X I and X Q contain Item, that is, the embodiment of the present application is that the introduction of the local oscillator light in the coherent receiving device increases the amplitude of the output current, thereby improving the sensitivity of the system detection.
  • the differential voltage signals X I and X Q contain the part ( ⁇ in - ⁇ lo ) ⁇ t of the frequency difference between the signal light and the local oscillator light. Therefore, the frequency detection of the differential voltage signals X I and X Q can be obtained.
  • the Doppler frequency shift of the signal light can be obtained, and the inversion of the wind speed can be realized by using the formula (1).
  • the formula of the differential voltage output after the differential current output by the PD array is amplified and converted by the TIA is as follows:
  • the differential voltage signals Y I and Y Q contain Item, that is, the embodiment of the present application is that the introduction of the local oscillator light in the coherent receiving device increases the amplitude of the output current, thereby improving the sensitivity of the system detection.
  • the differential voltage signals Y I and Y Q contain the part ( ⁇ in - ⁇ lo ) ⁇ t of the frequency difference between the signal light and the local oscillator light. Therefore, the frequency detection of the differential voltage signals Y I and Y Q can be obtained.
  • the Doppler frequency shift of the signal light can be obtained, and the inversion of the wind speed can be realized by using the formula (1).
  • the embodiment of the present application discloses a coherent receiving device and a wind-measuring lidar system.
  • the device includes: a polarization-maintaining fiber pin, a polarization beam splitter prism, a frequency mixer, a photodiode PD array, and a signal processing circuit;
  • the polarization-maintaining fiber ferrule is used to receive the local oscillator light and output the local oscillator light to the mixer, and the polarization state of the local oscillator light remains unchanged during transmission in the polarization-maintaining fiber ferrule
  • the polarization beam splitter prism is used to receive signal light, divide the signal light into a first signal light with p polarization state and a second signal light with s polarization state, and separate the first signal light and all
  • the second signal light is output to the mixer;
  • the mixer is configured to mix the first signal light and the second signal light with the local oscillator light respectively, and mix the frequencies
  • the coherent receiving device in the embodiment of the present application uses the interference of the local oscillator light and the signal light to perform Doppler frequency detection, and adopts the differential signal output method, which can eliminate common mode noise, improve the detection accuracy, and the Doppler frequency shift detection is not affected by the Due to the influence of laser wavelength drift, the coherent receiving device adopts a dual-polarization detection scheme, so that even if the polarization direction of the signal light changes, the Doppler frequency shift of the signal light can be effectively detected.
  • the embodiments described herein may be implemented in hardware, software, firmware, middleware, microcode, or a combination thereof.
  • the processing unit can be implemented in one or more Application Specific Integrated Circuits (ASIC), Digital Signal Processing (DSP), Digital Signal Processing Device (DSP Device, DSPD), programmable Logic Devices (Programmable Logic Device, PLD), Field-Programmable Gate Array (Field-Programmable Gate Array, FPGA), General Purpose Processors, Controllers, Microcontrollers, Microprocessors, Others for performing the functions described herein electronic unit or a combination thereof.
  • ASIC Application Specific Integrated Circuits
  • DSP Digital Signal Processing
  • DSP Device Digital Signal Processing Device
  • DSPD Digital Signal Processing Device
  • PLD programmable Logic Devices
  • Field-Programmable Gate Array Field-Programmable Gate Array
  • FPGA Field-Programmable Gate Array
  • the disclosed apparatus and system may be implemented in other manners.
  • the apparatus embodiments described above are only illustrative.
  • the division of the units is only a logical function division. In actual implementation, there may be other division methods.
  • multiple units or components may be combined, or Can be integrated into another system, or some features can be ignored, or not implemented.
  • the coupling, or direct coupling, or communication connection between the components shown or discussed may be through some interfaces, and the indirect coupling or communication connection of devices or units may be electrical, mechanical or other forms. of.
  • the unit described above as a separate component may or may not be physically separated, and the component displayed as a unit may or may not be a physical unit, that is, it may be located in one place or distributed to multiple network units; Some or all of the units may be selected according to actual needs to achieve the purpose of the solution in this embodiment.
  • each functional unit in each embodiment of the present application may all be integrated into one processing module, or each unit may be separately used as a unit, or two or more units may be integrated into one unit; the above integration
  • the unit can be implemented either in the form of hardware or in the form of hardware plus software functional units.
  • the aforementioned program can be stored in a computer-readable storage medium, and when the program is executed, execute Including the steps of the above method embodiment; and the aforementioned storage medium includes: a mobile storage device, a read-only memory (ROM, Read-Only Memory), a random access memory (RAM, Random Access Memory), a magnetic disk or an optical disk and other various A medium on which program code can be stored.
  • ROM read-only memory
  • RAM random access memory
  • magnetic disk or an optical disk and other various A medium on which program code can be stored.

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Electromagnetism (AREA)
  • General Physics & Mathematics (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Signal Processing (AREA)
  • Multimedia (AREA)
  • Aviation & Aerospace Engineering (AREA)
  • Optical Communication System (AREA)
  • Optical Radar Systems And Details Thereof (AREA)

Abstract

一种相干接收装置（310）及测风激光雷达系统，相干接收装置（310）包括：保偏光纤插针（110），用于接收本振光，并输出给混频器（130，230）；偏振分束棱镜（120，220），用于接收信号光，将信号光分成第一信号光和第二信号光，并将第一信号光和第二信号光输出给混频器（130，230）；混频器（130，230），用于将第一信号光和第二信号光分别与本振光进行混频，并将混频后的光输出给PD阵列（140，240）；PD阵列（140，240），用于对混频后的光进行光电转换，得到差分电流信号；信号处理电路（150，250），用于对差分电流信号进行转换，以得到差分电压信号；差分电压信号的推导公式中包括信号光和本振光频率差的部分，检测差分电压信号的频率，以得到信号光和本振光频率差的值；根据信号光和本振光频率差的值，得到信号光的多普勒频移量。

Description

一种相干接收装置及测风激光雷达系统
相关申请的交叉引用
本申请基于申请号为202011258199.X、申请日为2020年11月11日的中国专利申请提出，并要求该中国专利申请的优先权，该中国专利申请的全部内容在此引入本申请作为参考。
技术领域
本申请涉及光通信技术领域，尤其涉及一种相干接收装置及测风激光雷达系统。
背景技术
测风多普勒激光雷达是一种高精度、高分辨率的大气风场探测技术，在大气动力学研究，天气预报和大气环境监测等领域都有广泛应用，传统的多普勒频移探测方法有边缘检测技术和条纹成像技术。主要采用法布里-珀罗谐振腔、马赫-曾德干涉仪、菲索干涉仪等产生的环形条纹或线形条干涉图案，将信号的频率变化转化为相对能量的变化来测定多普勒频移。这种频移探测方法一般需要用面形电荷耦合器件(Charge-coupled Device，CCD)来接收干涉图案，面形CCD体积较大，而且通过该方法接收到的回波信号的能量通常较弱，探测到的能量也较弱，由于该能量会受系统噪声的影响，从而对多普勒频移探测造成一定的误差。
发明内容
有鉴于此，本申请实施例为解决现有技术中存在的至少一个问题而提供一种相干接收装置及测风激光雷达系统。
为达到上述目的，本申请实施例的技术方案是这样实现的：
第一方面，本申请实施例提供一种相干接收装置，所述装置包括：保偏光纤插针、偏振分束棱镜、混频器、光电二极管PD阵列和信号处理电路；其中，
所述保偏光纤插针，用于接收本振光，并将所述本振光输出给所述混频器，所述本振光在所述保偏光纤插针中传输时偏振态保持不变；
所述偏振分束棱镜，用于接收信号光，将所述信号光分成具有p偏振态的第一信号光和具有s偏振态的第二信号光，并将所述第一信号光和所述第二信号光输出给所述混频器；
所述混频器，用于将所述第一信号光和所述第二信号光分别与所述本振光进行混频，并将混频后的光输出给所述PD阵列；
所述PD阵列，用于对所述混频后的光进行光电转换，得到差分电流信号；
所述信号处理电路，用于对所述差分电流信号进行转换，以得到差分电压信号；所述差分电压信号的推导公式中包括所述信号光和所述本振光频率差的部分，检测所述差分电压信号的频率，以得到所述信号光和所述本振光频率差的值；根据所述信号光和所述本振光频率差的值，得到所述信号光的多普勒频移量。
在一种可选的实施方式中，所述信号处理电路包括：放大器模块、模数转换器和处理器；其中，
所述放大器模块，用于对所述差分电流信号进行放大，并将所述差分电流信号转换成差分电压信号；
所述模数转换器，用于对所述差分电压信号进行模数转换器ADC采样，得到ADC采样信号；
所述处理器，用于对所述ADC采样信号进行处理，得到所述ADC采样信号的频率，所述ADC采样信号的频率为所述信号光的多普勒频移量。
在一种可选的实施方式中，所述差分电压信号的推导公式为
Figure PCTCN2020135327-appb-000001
和
Figure PCTCN2020135327-appb-000002
Figure PCTCN2020135327-appb-000003
其中，R为所述PD阵列中光电二极管的响应度，G为放大器模块的跨组增益，P in为信号光光强，P lo为本振光光强，ω in为信号光角频率，ω lo为本振光角频率；θ in为信号光初始相位，θ lo为本振光初始相位，δ为所述第一信号光和所述第二信号光与水平方向的夹角；
检测所述差分电压信号的频率，以确定所述差分电压信号的推导公式中的(ω in-ω lo)×t项的值；
所述差分电压信号的推导公式中的(ω in-ω lo)×t项的值为所述信号光的多普勒频移量。
在一种可选的实施方式中，所述放大器模块采用低带宽放大器，还用于实现对所述差分电流信号的高频滤波。
在一种可选的实施方式中，所述信号光的多普勒频移量用于确定风速。
在一种可选的实施方式中，所述装置还包括：设置在所述PD阵列与所述放大器模块之间的低频滤波电路；其中，
所述低频滤波电路，用于控制所述差分电流信号的截止频率，以实现对所述差分电流信号的低频滤波。
在一种可选的实施方式中，所述信号光基于以下方式生成：由激光器发射的激光进入大气中并与大气中的气溶胶分子发生相互作用产生回波信号，所述回波信号为所述信号光。
在一种可选的实施方式中，所述本振光为所述激光器发射进入所述保偏光纤插针的激光。
在一种可选的实施方式中，所述混频器包括第一子混频器和第二子混频器；其中，
所述第一子混频器，用于对所述第一信号光和所述本振光进行混频；
所述第二子混频器，用于对所述第二信号光和所述本振光进行混频。
在一种可选的实施方式中，所述装置还包括：设置在所述混频器与所述PD阵列之间的反射棱镜和透镜阵列；其中，
所述混频器输出的混频后的光经过所述反射棱镜反射以及所述透镜阵列汇聚后，再输出给所述PD阵列。
在一种可选的实施方式中，所述装置还包括：设置在所述偏振分束棱镜与所述混频器之间的两个C透镜；其中，
所述偏振分束棱镜输出的所述第一信号光和所述第二信号光分别通过所述两个C透镜汇聚进入所述混频器。
第二方面，本申请实施例提供一种测风激光雷达系统，包括：如第一方面所述的相干接收装置、激光单元和望远系统；其中，
所述激光单元，用于发射激光，将所述激光分为第一部分激光以及第二部分激光；将所述第一部分激光输出给所述望远系统，以及将所述第二部分激光输出给所述相干接收装置；
所述望远系统，用于将所述第一部分激光射入大气中，接收和大气中的气溶胶分子发生相互作用的回波信号，并将所述回波信号输出给所述相干接收装置；
所述相干接收装置，用于接收所述第二部分激光作为本振光，将所述本振光与所述回波信号进行干涉，形成解调信号，通过所述解调信号得到所述回波信号的多普勒频移量，根据所述多普勒频移量确定风速。
在一种可选的实施方式中，所述激光单元包括：激光器和分束器；其中，
所述激光器，用于发射激光；
所述分束器，用于将所述激光分为具有第一能量的第一部分激光以及具有第二能量的第二部分激光，所述第一能量小于所述第二能量。
本申请实施例公开了一种相干接收装置及测风激光雷达系统，所述装置包括：保偏光纤插针、偏振分束棱镜、混频器、光电二极管PD阵列和信号处理电路；其中，所述保偏光纤插针，用于接收本振光，并将所述本振光输出给所述混频器，所述本振光在所述保偏光纤插针中传输时偏振态保持不变；所述偏振分束棱镜，用于接收信号光，将所述信号光分成具有p偏振态的第一信号光和具有s偏振态的第二信号光，并将所述第一信号光和所述第二信号光输出给所述混频器；所述混频器，用于将所述第一信号光和所述第二信号光分别与所述本振光进行混频，并将混频后的光输出给所述PD阵列；所述PD阵列，用于对所述混频后的光进行光电转换，得到差分电流信号；所述信号处理电路，用于对所述差分电流信号进行转换，以得到差分电压信号；所述差分电压信号的推导公式中包括所述信号光和所述本振光频率差的部分，检测所述差分电压信号的频率，以得到所述信号光和所述本振光频率差的值；根据所述信号光和所述本振光频率差的值，得到所述信号光的多普勒频移量。本申请实施例中的相干接收装置采用本振光与信号光干涉进行多普勒频率检测，且采用差分信号输出方式，能够消除共模噪声，提高检测精度，且多普勒频移检测不受激光器波长漂移的影响，相干接收装置采用双偏振检测方案，从而即使信号光改变了偏振方向，也能对信号光的多普勒频移进行有效检测。
附图说明
图1为本申请实施例提供的一种相干接收装置的结构示意图；
图2为本申请实施例提供的混频器与PD阵列之间的转向结构的示意图；
图3为本申请实施例提供的另一种相干接收装置的结构示意图；
图4为本申请实施例提供的PD阵列和放大器模块之间的连接结构示意图；
图5为本申请实施例提供的一种测风激光雷达系统的结构示意图；
图6为大气传输窗口及人眼伤害阈值曲线图；
图7为本申请实施例提供的一种相干接收装置的电路结构示意图；
图8为本申请实施例提供的一种90度混频器的结构示意图；
图9为本申请实施例提供的一种3dB耦合器的端口相位差示意图。
具体实施方式
下面将参照附图更详细地描述本申请公开的示例性实施方式。虽然附图中显示了本申请的示例性实施方式，然而应当理解，可以以各种形式实现本申请，而不应被这里阐述的具体实施方式所限制。相反，提供这些实施方式是为了能够更透彻地理解本申请，并且能够将本申请公开的范围完整的传达给本领域的技术人员。
在下文的描述中，给出了大量具体的细节以便提供对本申请更为彻底的理解。然而，对于本领域技术人员而言显而易见的是，本申请可以无需一个或多个这些细节而得以实施。在其他的例子中，为了避免与本申请发生混淆，对于本领域公知的一些技术特征未进行描述；即，这里不描述实际实施例的全部特征，不详细描述公知的功能和结构。
在附图中，为了清楚，层、区、元件的尺寸以及其相对尺寸可能被夸大。自始至终相同附图标记表示相同的元件。
应当明白，空间关系术语例如“在……下”、“在……下面”、“下面的”、“在……之下”、“在……之上”、“上面的”等，在这里可为了方便描述而被使用从而描述图中所示的一个元件或特征与其它元件或特征的关系。应当明白，除了图中所示的取向以外，空间关系术语意图还包括使用和操作中的器件的不同取向。例如，如果附图中的器件翻转，然后，描述为“在其它元件下面”或“在其之下”或“在其下”元件或特征将取向为在其它元件或特征“上”。因此，示例性术语“在……下面”和“在……下”可包括上和下两个取向。器件可以另外地取向(旋转90度或其它取向)并且在 此使用的空间描述语相应地被解释。
在此使用的术语的目的仅在于描述具体实施例并且不作为本申请的限制。在此使用时，单数形式的“一”、“一个”和“所述/该”也意图包括复数形式，除非上下文清楚指出另外的方式。还应明白术语“组成”和/或“包括”，当在该说明书中使用时，确定所述特征、整数、步骤、操作、元件和/或部件的存在，但不排除一个或更多其它的特征、整数、步骤、操作、元件、部件和/或组的存在或添加。在此使用时，术语“和/或”包括相关所列项目的任何及所有组合。
图1为本申请实施例提供的一种相干接收装置的结构示意图，如图1所示，所述相干接收装置包括：保偏光纤插针110、偏振分束棱镜120、混频器130、光电二极管(Photo-Diode，PD)阵列140和信号处理电路150；其中，
所述保偏光纤插针110，用于接收本振光，并将所述本振光输出给所述混频器130，所述本振光在所述保偏光纤插针110中传输时偏振态保持不变；
所述偏振分束棱镜120，用于接收信号光，将所述信号光分成具有p偏振态的第一信号光和具有s偏振态的第二信号光，并将所述第一信号光和所述第二信号光输出给所述混频器130；
所述混频器130，用于将所述第一信号光和所述第二信号光分别与所述本振光进行混频，并将混频后的光输出给所述PD阵列140；
所述PD阵列140，用于对所述混频后的光进行光电转换，得到差分电流信号；
所述信号处理电路150，用于对所述差分电流信号进行转换，以得到差分电压信号；所述差分电压信号的推导公式中包括所述信号光和所述本振光频率差的部分，检测所述差分电压信号的频率，以得到所述信号光和所述本振光频率差的值；根据所述信号光和所述本振光频率差的值，得到所述信号光的多普勒频移量。
在本申请实施例中，所述相干接收装置有两路输入光：一路为信号光，另一路为本振光。所述信号光和所述本振光均为同一激光器产生的激光，所述信号光基于以下方式生成：由激光器发射的激光进入大气中并与大气中的气溶胶分子发生相互作用产生回波信号，所述回波信号为所述信号光。所述本振光为所述激光器发射进入所述保偏光纤插针110的激光。其中，信号光为与大气中的气溶胶分子发生相互作用的回波信号，其偏振态不确定；本振光为偏振光。本申请实施例在相干接收装置中引入本振光，能够提高多普勒频移检测的灵敏度，并消除因激光器长时间工作或者外界环境发生变化而产生的频率漂移。
在本申请实施例中，所述相干接收装置还包括：设置在所述偏振分束棱镜120与所述混频器130之间的两个C透镜160；其中，所述偏振分束棱镜120输出的所述第一信号光和所述第二信号光分别通过所述两个C透镜160汇聚进入所述混频器130。在本申请实施例中所述两个C透镜160与所述混频器130直接粘接在一起，所述两个C透镜160用于对输入所述混频器130的所述第一信号光和所述第二信号光进行汇聚。当器件外界冲击或者外界环境温度发生变化时，由于所述两个C透镜160与所述混频器130粘接在一起，因此所述两个C透镜160与所述混频器130之间不会发生相对位移(即所述两个C透镜160和所述混频器130一起发生位置变化)，即本申请实施例中采用两个C透镜与混频器粘接在一起的设置方案具有更好的稳定性和温度特性。且所述第一信号光和所述第二信号光的光路对位置容差较大，即使所述两个C透镜160和所述混频器130一起发生位置变化对耦合效率的影响也较小。
在本申请实施例中，所述相干接收装置还包括：基板170；其中，所述偏振分束棱镜120、所述两个C透镜160、所述混频器130和所述PD阵列140设置在所述基板170上。
在本申请实施例中，所述偏振分束棱镜120由两块棱镜胶合组成，两 块棱镜的胶合面设置有偏振分束膜，当信号光到达胶合面时，偏振态平行于输入光线及法线平面的第一信号光(p偏振态)透过偏振分束膜继续向前传播，并射出偏振分束棱镜120；偏振态垂直于输入光线及法线平面内的第二信号光(s偏振态)在偏振分束膜处发生反射转向(90度)，并在偏振分束棱镜120的斜面再次反射转向(90度)，从而形成与第一信号光平行的第二信号光，射出偏振分束棱镜120。
在本申请实施例中，所述混频器130包括一个本振端口和两个信号端口，所述本振端口与保偏光纤插针110连接，所述两个信号端口分别与所述两个C透镜160连接。保偏光纤插针110与混频器130的本振端口可以通过紫外胶(Ultraviolet Rays)粘接在一起；所述两个C透镜160与混频器130的两个信号端口可以通过紫外胶耦合粘接在一起。
在本申请实施例中，第一信号光和第二信号光分别通过2个C透镜160汇聚进入混频器130中，所述混频器130包括第一子混频器和第二子混频器；其中，所述第一子混频器，用于对所述第一信号光和所述本振光进行混频；所述第二子混频器，用于对所述第二信号光和所述本振光进行混频。所述第一子混频器和所述第二子混频器可以为90度混频器。所述信号光的两个偏振态光(第一信号光和第二信号光)分别与本振光在对应的90度混频器中混频后，通过混频器130给所述PD阵列140。所述2个C透镜160设置在所述基板170上。
在本申请实施例中，所述信号处理电路150包括：放大器模块、模数转换器和处理器；其中，所述放大器模块，用于对所述差分电流信号进行放大，并将所述差分电流信号转换成差分电压信号；所述模数转换器，用于对所述差分电压信号进行模数转换器(Analog to Digital Converter，ADC)采样，得到ADC采样信号；所述处理器，用于对所述ADC采样信号进行处理，得到所述ADC采样信号的频率，所述ADC采样信号的频率即为所述信号光的多普勒频移量。根据所述信号光的多普勒频移量即可确定风速。 本申请实施例中相干接收装置采用差分信号输出方式，能够消除系统共模噪声，提高检测精度。在一些实施例中，所述信号处理电路150可以只包括放大器模块，所述信号处理电路150将所述放大器模块放大并转化后的差分电压信号通过所述相干接收装置的管壳针脚输出至管壳外部，由管壳外部的模数转换器和处理器对差分电压信号进行处理，以得到所述信号光的多普勒频移量。
在本申请实施例中，所述PD阵列140与所述放大器模块之间还设有一低频滤波电路，所述低频滤波电路，用于控制所述差分电流信号的截止频率，以实现对所述差分电流信号的低频滤波。
在本申请实施例中，所述放大器模块可以采用低带宽放大器，从而还可以用于实现对所述差分电流信号的高频滤波。本申请实施例中通过低带宽放大器对所述差分电流信号进行放大，从而可以有效降低电路中的1/f噪声，提高信噪比。
在本申请实施例中，所述PD阵列140与所述信号处理电路150通过金线进行电连接，从而所述PD阵列140输出的差分电流信号可以通过金线发送给所述信号处理电路150。
由于所述PD阵列140设置在基板170上，且PD阵列140中的光电二极管的光敏面朝上，而所述混频器130输出的混频后的光的方向平行于光电二极管的光敏面，因此需要将混频后的光进行转向后再射入PD阵列140中的光电二极管的光敏面上。图2为本申请实施例提供的混频器与PD阵列之间的转向结构的示意图，如图2所示，所述相干接收装置还包括：设置在所述混频器130与所述PD阵列140之间的反射棱镜180和透镜阵列190；其中，所述混频器130输出的混频后的光经过所述反射棱镜180反射以及所述透镜阵列190汇聚后，再输出给所述PD阵列140。混频器130输出的混频后的光通过反射棱镜180进行90度的转向，转向后的光信号经过透镜阵列190汇聚进入PD阵列140。在一些实施例中，PD阵列140两侧设置 有透镜支架1100，透镜支架1100用于固定透镜阵列190，以使所述透镜阵列190通光面的中心与PD阵列140光敏面的中心对准。所述透镜支架1100设置在所述基板170上。
在本申请实施例中，所述相干接收装置还包括：准直器1200；其中，所述准直器1200，用于对输入相干接收装置的信号光进行准直，并将准直后的信号光输出给偏振分束棱镜120。所述准直器1200也设置在所述基板170上。
在本申请实施例中，所述相干接收装置还包括：管壳1300；其中，所述基板170和所述信号处理电路150设置在所述管壳1300内。需要说明的是，所述基板170上设置的器件也均位于所述管壳1300内。
在本申请另一实施例中，所述相干接收装置还可以采用设置光窗的方式，在光窗中设置准直器，从而将准直后的信号光和本振光输入至所述相干接收装置内。图3为本申请实施例提供的另一种相干接收装置的结构示意图，如图3所示，所述相干接收装置包括：光窗210、偏振分束棱镜220、混频器230、PD阵列240和信号处理电路250；其中，
所述光窗210，用于接收本振光和信号光，并将所述本振光输出给所述混频器230，将所述信号光输出给所述偏振分束棱镜220；
所述偏振分束棱镜220，用于接收信号光，将所述信号光分成具有p偏振态的第一信号光和具有s偏振态的第二信号光，并将所述第一信号光和所述第二信号光输出给所述混频器230；
所述混频器230，用于将所述第一信号光和所述第二信号光分别与所述本振光进行混频，并将混频后的光输出给所述PD阵列240；
所述PD阵列240，用于对所述混频后的光进行光电转换，得到差分电流信号；
所述信号处理电路250，用于对所述差分电流信号进行处理，得到所述信号光的多普勒频移量。
在本申请实施例中，所述相干接收装置还包括：设置在所述偏振分束棱镜220与所述混频器230之间的两个C透镜260；其中，所述偏振分束棱镜220输出的所述第一信号光和所述第二信号光分别通过所述两个C透镜260汇聚进入所述混频器240。
在本申请实施例中，所述相干接收装置还包括：设置在所述光窗210与所述混频器230之间的C透镜270；其中，所述光窗210输出的所述本振光通过所述C透镜270汇聚进入所述混频器240。
图4为本申请实施例提供的PD阵列和放大器模块之间的连接结构示意图，如图4所示，PD阵列中每两个PD器件和一个低带宽放大器TIA连接，两个PD器件串联，一端接Vcc，一端接地，Vcc为PD器件提供反偏电压。所述放大器模块由一低带宽放大器TIA和与低带宽放大器TIA并联的电阻R2和电容C2组成，通过调整R2和C2的大小，可以控制低带宽放大器TIA的增益和带宽的大小，从而能够控制低带宽放大器TIA的滤波的大小。PD阵列和低带宽放大器TIA之间设有一个低频滤波电路，该低频滤波电路由串联的电阻R1和电容C1组成，通过调整R1和C1的大小，能够控制PD阵列输出的差分电流信号的截止频率，从而能够消除进入低带宽放大器TIA的直流光信号，以实现对所述差分电流信号的低频滤波。需要说明的是，截止频率大小可以根据相干接收装置的实际使用带宽来进行调整。
图5为本申请实施例提供的一种测风激光雷达系统的结构示意图，如图5所示，所述测风激光雷达系统包括：相干接收装置310、激光单元320和望远系统330；其中，
所述激光单元320，用于发射激光，将所述激光分为第一部分激光以及第二部分激光；将所述第一部分激光输出给所述望远系统330，以及将所述第二部分激光输出给所述相干接收装置310；
所述望远系统330，用于将所述第一部分激光射入大气中，接收和大气中的气溶胶分子发生相互作用的回波信号，并将所述回波信号输出给所述 相干接收装置310；
所述相干接收装置310，用于接收所述第二部分激光作为本振光，将所述本振光与所述回波信号进行干涉，形成解调信号，通过所述解调信号得到所述回波信号的多普勒频移量，根据所述多普勒频移量确定风速。
在本申请实施例中，所述激光单元320包括：激光器321和分束器322；其中，所述激光器321，用于发射激光；所述分束器322，用于将所述激光分为具有第一能量的第一部分激光以及具有第二能量的第二部分激光，所述第一能量小于所述第二能量。在一些实施例中，激光器321产生的激光通过分束器322将所述激光按照一定比例进行分束，例如按照9：1的比例进行分束，90％的激光作为本振光输出给所述相干接收装置310，10％的激光通过望远系统330发射进入大气中，使得激光与大气中的气溶胶分子发生相互作用而产生回波信号，望远系统330接收回波信号，并将所述回波信号作为信号光输出给相干接收装置310。在实际应用时，所述激光器321可以发射单偏振窄线宽光源。优选光发射波长为1.55um的激光器。
图6为大气传输窗口及人眼伤害阈值曲线图，图6中横坐标是光束波长(um)，MPE是人眼的最大曝光量，点状曲线是人眼对光束光强安全曲线，从该曲线可知1.5-1.8um波长的激光对人眼有更高的安全阈值。1.55um波长的激光的最大允许曝光量是2.1um波长激光的10倍，高出1.06um波长的激光5个数量级。而且1.55um波长的激光比较常用，1.55um的分束器、环形器比较常见，因此本申请实施例中的测风激光雷达系统选择1.55um波长的激光，即能兼容现有标准器件的波长范围，对人眼又有较高的安全阈值。
在本申请实施例中，所述测风激光雷达系统还包括：位于所述激光单元320和所述望远系统330之间的环形器340。所述分束器322将所述激光分为具有第一能量的第一部分激光以及具有第二能量的第二部分激光后，将所述第一部分激光输出给环形器340的1端口，所述第一部分激光从环 形器340的2端口输出给望远系统330，望远系统330将所述第一部分激光射入大气中，第一部分激光与大气中的气溶胶分子发生相互作用(如弹性散射)，后向散射的回波信号被望远系统330接收，并输出给环形器340的2端口，回波信号由环形器340的3端口输出给相干接收装置310。其中，望远系统330可以为激光准直系统，该激光准直系统能够把环形器340中小模场发散光源准直成为大模场平行光束，从而能够传输更远距离。
在本申请实施例中，激光器发射中心波长为λ的激光到大气中，由于悬浮于大气中随风运动的气溶胶分子对激光具有散射作用，假设风速V在望远系统的视向的分量为V×cos(θ)，则测风激光雷达系统接收到的后向散射的光信号会产生与气溶胶分子的径向运动速度成正比的多普勒频移△f，多普勒频移△f的公式如下：
Figure PCTCN2020135327-appb-000004
其中，±表示气溶胶分子的径向运动方向。因此，确定测风激光雷达系统接收到的后向散射的光信号的多普勒频移，即可根据多普勒频移得到气溶胶分子的径向风速。
混频器包括第一子混频器和第二子混频器，第一子混频器和第二子混频器分别将信号光的两个正交偏振态(第一信号光和第二信号光)与本振光进行混频，以实现对信号光的频移解调。假设信号光电场为E in，本振光电场E lo，信号光电场为E in和本振光电场E lo的公式如下：
Figure PCTCN2020135327-appb-000005
Figure PCTCN2020135327-appb-000006
其中，P in为信号光光强，P lo为本振光光强；ω in为信号光角频率，ω lo为本振光角频率；θ in为信号光初始相位，θ lo为本振光初始相位。
当信号光通过偏振分束器时，设信号的两个光偏振态(s偏振态和p偏振态)与水平方向(入射方向与法线组成的平面)夹角为δ时，根据马吕 斯定律可以得到光强公式，p偏振态的第一信号光的光强P p和s偏振态的第二信号光的光强P s的公式如下：
P p＝P in×(cosδ) 2       (4)
P s＝P in×(sinδ) 2       (5)
图7为本申请实施例提供的一种相干接收装置的电路结构示意图，如图6所示，信号光经偏振分束器分成具有p偏振态的第一信号光和具有s偏振态的第二信号光，偏振分束器将所述第一信号光和所述第二信号光分别输出给第一子混频器(90度混频器)和第二子混频器(90度混频器)；本振光经分束器分成两束相同的本振光，分别输出给第一子混频器(90度混频器)和第二子混频器(90度混频器)。图8为本申请实施例提供的一种90度混频器的结构示意图，如图8所示，单个90度混频器包括4个3dB耦合器和一个90度相位延迟器。相位延迟器为一段额外波导，其长度等于激光波长的四分之一，能够产生90度的相移。本振光经分束器分成两束相同的本振光，则进入单个90度混频器的本振光的光强为
Figure PCTCN2020135327-appb-000007
图9为本申请实施例提供的一种3dB耦合器的端口相位差示意图，如图9所示，3dB耦合器的一个端口输出π+d θ，另一个端口输出0°。对于具有p偏振态的第一信号光来说，所述第一信号光与本振光经第一子混频器(90度混频器)进行混频后输出的电场的公式如下：
Figure PCTCN2020135327-appb-000008
Figure PCTCN2020135327-appb-000009
Figure PCTCN2020135327-appb-000010
Figure PCTCN2020135327-appb-000011
设放大器模块(TIA)的跨组增益为G，PD阵列中光电二极管的响应 度为R，则PD阵列输出的差分电流经TIA放大和转换后输出的差分电压的公式如下：
X I＝R×G×(|E 1| 2-|E 2| 2)       (10)
将公式(6)和(7)代入公式(10)可得：
Figure PCTCN2020135327-appb-000012
X Q＝R×G×(|E 3| 2-|E 4| 2)       (12)
将公式(8)和(9)代入公式(12)可得：
Figure PCTCN2020135327-appb-000013
其中，
Figure PCTCN2020135327-appb-000014
是90度相位延迟器的相位误差，
Figure PCTCN2020135327-appb-000015
具有波长相关性，对于平面光波导的混频器，
Figure PCTCN2020135327-appb-000016
的波长相关性约为-0.045(°/nm)；d θ是3dB耦合器的2个输出端口之间的相位误差，同样d θ具有波长相关性，d θ的波长相关性约为-0.021(°/nm)。本申请实施例中采用的是单一波长的激光器，因此，
Figure PCTCN2020135327-appb-000017
和d θ在本申请实施例中不具有波长相关性，从而使得
Figure PCTCN2020135327-appb-000018
和d θ＝0。在此种情况下，差分电压X I和X Q的公式如下：
Figure PCTCN2020135327-appb-000019
Figure PCTCN2020135327-appb-000020
由公式(14)和公式(15)可知差分电压信号X I和X Q中包含有
Figure PCTCN2020135327-appb-000021
项，即本申请实施例是相干接收装置中本振光的引入提高了输出电流的幅值，从而提高了系统检测的灵敏度。且差分电压信号X I和X Q中包含了信号光和本振光频率差的部分(ω in-ω lo)×t，因此，对差分电压信号X I和X Q进行频率检测，即可求得信号光的多普勒频移量，利用公式(1)即可以实现风速的反演。
对于具有s偏振态的第二信号光来说，所述第二信号光与本振光经第二子混频器(90度混频器)进行混频和输出的电场强度的公式如下：
Figure PCTCN2020135327-appb-000022
Figure PCTCN2020135327-appb-000023
Figure PCTCN2020135327-appb-000024
Figure PCTCN2020135327-appb-000025
设放大器模块(TIA)的跨组增益为G，PD阵列中光电二极管的响应度为R，则PD阵列输出的差分电流经TIA放大和转换后输出的差分电压的公式如下：
Y I＝R×G×(|E 1| 2-|E 2| 2)      (20)
将公式(16)和(17)代入公式(20)可得：
Figure PCTCN2020135327-appb-000026
Y Q＝R×F×(|E 3| 2-|E 4| 2)       (22)
将公式(18)和(19)代入公式(22)可得：
Figure PCTCN2020135327-appb-000027
其中，
Figure PCTCN2020135327-appb-000028
是90度相位延迟器的相位误差，
Figure PCTCN2020135327-appb-000029
具有波长相关性，对于平面光波导的混频器，
Figure PCTCN2020135327-appb-000030
的波长相关性约为-0.045(°/nm)；d θ是3dB耦合器的2个输出端口之间的相位误差，同样d θ具有波长相关性，d θ的波长相关性约为-0.021(°/nm)。本申请实施例中采用的是单一波长的激光器，因此，
Figure PCTCN2020135327-appb-000031
和d θ在本申请实施例中不具有波长相关性，从而使得
Figure PCTCN2020135327-appb-000032
和d θ＝0。 在此种情况下，差分电压Y I和Y Q的公式如下：
Figure PCTCN2020135327-appb-000033
Figure PCTCN2020135327-appb-000034
由公式(24)和公式(25)可知差分电压信号Y I和Y Q中包含有
Figure PCTCN2020135327-appb-000035
项，即本申请实施例是相干接收装置中本振光的引入提高了输出电流的幅值，从而提高了系统检测的灵敏度。且差分电压信号Y I和Y Q中包含了信号光和本振光频率差的部分(ω in-ω lo)×t，因此，对差分电压信号Y I和Y Q进行频率检测，即可求得信号光的多普勒频移量，利用公式(1)即可以实现风速的反演。
本申请实施例公开了一种相干接收装置及测风激光雷达系统，所述装置包括：保偏光纤插针、偏振分束棱镜、混频器、光电二极管PD阵列和信号处理电路；其中，所述保偏光纤插针，用于接收本振光，并将所述本振光输出给所述混频器，所述本振光在所述保偏光纤插针中传输时偏振态保持不变；所述偏振分束棱镜，用于接收信号光，将所述信号光分成具有p偏振态的第一信号光和具有s偏振态的第二信号光，并将所述第一信号光和所述第二信号光输出给所述混频器；所述混频器，用于将所述第一信号光和所述第二信号光分别与所述本振光进行混频，并将混频后的光输出给所述PD阵列；所述PD阵列，用于对所述混频后的光进行光电转换，得到差分电流信号；所述信号处理电路，用于对所述差分电流信号进行转换，以得到差分电压信号；所述差分电压信号的推导公式中包括所述信号光和所述本振光频率差的部分，检测所述差分电压信号的频率，以得到所述信号光和所述本振光频率差的值；根据所述信号光和所述本振光频率差的值，得到所述信号光的多普勒频移量。本申请实施例中的相干接收装置采用本振光与信号光干涉进行多普勒频率检测，且采用差分信号输出方式，能够 消除共模噪声，提高检测精度，且多普勒频移检测不受激光器波长漂移的影响，相干接收装置采用双偏振检测方案，从而即使信号光改变了偏振方向，也能对信号光的多普勒频移进行有效检测。
可以理解的是，本文描述的这些实施例可以用硬件、软件、固件、中间件、微码或其组合来实现。对于硬件实现，处理单元可以实现在一个或多个专用集成电路(Application Specific Integrated Circuits，ASIC)、数字信号处理器(Digital Signal Processing，DSP)、数字信号处理设备(DSP Device，DSPD)、可编程逻辑设备(Programmable Logic Device，PLD)、现场可编程门阵列(Field-Programmable Gate Array，FPGA)、通用处理器、控制器、微控制器、微处理器、用于执行本申请所述功能的其它电子单元或其组合中。
应理解，说明书通篇中提到的“一个实施例”或“一实施例”意味着与实施例有关的特定特征、结构或特性包括在本申请的至少一个实施例中。因此，在整个说明书各处出现的“在一个实施例中”或“在一实施例中”未必一定指相同的实施例。此外，这些特定的特征、结构或特性可以任意适合的方式结合在一个或多个实施例中。应理解，在本申请的各种实施例中，上述各过程的序号的大小并不意味着执行顺序的先后，各过程的执行顺序应以其功能和内在逻辑确定，而不应对本申请实施例的实施过程构成任何限定。上述本申请实施例序号仅仅为了描述，不代表实施例的优劣。
在本申请所提供的几个实施例中，应该理解到，所揭露的装置和系统，可以通过其它的方式实现。以上所描述的装置实施例仅仅是示意性的，例如，所述单元的划分，仅仅为一种逻辑功能划分，实际实现时可以有另外的划分方式，如：多个单元或组件可以结合，或可以集成到另一个系统，或一些特征可以忽略，或不执行。另外，所显示或讨论的各组成部分相互之间的耦合、或直接耦合、或通信连接可以是通过一些接口，设备或单元的间接耦合或通信连接，可以是电性的、机械的或其它形式的。
上述作为分离部件说明的单元可以是、或也可以不是物理上分开的，作为单元显示的部件可以是、或也可以不是物理单元，即可以位于一个地方，也可以分布到多个网络单元上；可以根据实际的需要选择其中的部分或全部单元来实现本实施例方案的目的。
另外，在本申请各实施例中的各功能单元可以全部集成在一个处理模块中，也可以是各单元分别单独作为一个单元，也可以两个或两个以上单元集成在一个单元中；上述集成的单元既可以采用硬件的形式实现，也可以采用硬件加软件功能单元的形式实现。本领域普通技术人员可以理解：实现上述方法实施例的全部或部分步骤可以通过程序指令相关的硬件来完成，前述的程序可以存储于一计算机可读取存储介质中，该程序在执行时，执行包括上述方法实施例的步骤；而前述的存储介质包括：移动存储设备、只读存储器(ROM，Read-Only Memory)、随机存取存储器(RAM，Random Access Memory)、磁碟或者光盘等各种可以存储程序代码的介质。
本申请所提供的几个产品实施例中所揭露的特征，在不冲突的情况下可以任意组合，得到新的产品实施例。
本申请所提供的几个系统或设备实施例中所揭露的特征，在不冲突的情况下可以任意组合，得到新的系统实施例或设备实施例。
以上所述，仅为本申请的具体实施方式，但本申请的保护范围并不局限于此，任何熟悉本技术领域的技术人员在本申请揭露的技术范围内，可轻易想到变化或替换，都应涵盖在本申请的保护范围之内。因此，本申请的保护范围应以所述权利要求的保护范围为准。

Claims (13)

  1. 一种相干接收装置，所述装置包括：保偏光纤插针、偏振分束棱镜、混频器、光电二极管PD阵列和信号处理电路；其中，
    所述保偏光纤插针，用于接收本振光，并将所述本振光输出给所述混频器，所述本振光在所述保偏光纤插针中传输时偏振态保持不变；
    所述偏振分束棱镜，用于接收信号光，将所述信号光分成具有p偏振态的第一信号光和具有s偏振态的第二信号光，并将所述第一信号光和所述第二信号光输出给所述混频器；
    所述混频器，用于将所述第一信号光和所述第二信号光分别与所述本振光进行混频，并将混频后的光输出给所述PD阵列；
    所述PD阵列，用于对所述混频后的光进行光电转换，得到差分电流信号；
    所述信号处理电路，用于对所述差分电流信号进行转换，以得到差分电压信号；所述差分电压信号的推导公式中包括所述信号光和所述本振光频率差的部分，检测所述差分电压信号的频率，以得到所述信号光和所述本振光频率差的值；根据所述信号光和所述本振光频率差的值，得到所述信号光的多普勒频移量。
  2. 根据权利要求1所述的相干接收装置，其中，所述信号处理电路包括：放大器模块、模数转换器和处理器；其中，
    所述放大器模块，用于对所述差分电流信号进行放大，并将所述差分电流信号转换成差分电压信号；
    所述模数转换器，用于对所述差分电压信号进行模数转换器ADC采样，得到ADC采样信号；
    所述处理器，用于对所述ADC采样信号进行处理，得到所述ADC采样信号的频率，所述ADC采样信号的频率为所述信号光的多普勒频移量。
  3. 根据权利要求2所述的相干接收装置，其中，
    所述差分电压信号的推导公式为
    Figure PCTCN2020135327-appb-100001
    和
    Figure PCTCN2020135327-appb-100002
    Figure PCTCN2020135327-appb-100003
    其中，R为所述PD阵列中光电二极管的响应度，G为放大器模块的跨组增益，P in为信号光光强，P lo为本振光光强，ω in为信号光角频率，ω lo为本振光角频率；θ in为信号光初始相位，θ lo为本振光初始相位，δ为所述第一信号光和所述第二信号光与水平方向的夹角；
    检测所述差分电压信号的频率，以确定所述差分电压信号的推导公式中的(ω in-ω lo)×t项的值；
    所述差分电压信号的推导公式中的(ω in-ω lo)×t项的值为所述信号光的多普勒频移量。
  4. 根据权利要求2所述的相干接收装置，其中，
    所述放大器模块采用低带宽放大器，还用于实现对所述差分电流信号的高频滤波。
  5. 根据权利要求2所述的相干接收装置，其中，
    所述信号光的多普勒频移量用于确定风速。
  6. 根据权利要求2所述的相干接收装置，其中，所述装置还包括：设置在所述PD阵列与所述放大器模块之间的低频滤波电路；其中，
    所述低频滤波电路，用于控制所述差分电流信号的截止频率，以实现对所述差分电流信号的低频滤波。
  7. 根据权利要求1所述的相干接收装置，其中，
    所述信号光基于以下方式生成：由激光器发射的激光进入大气中并与大气中的气溶胶分子发生相互作用产生回波信号，所述回波信号为所述信 号光。
  8. 根据权利要求7所述的相干接收装置，其中，
    所述本振光为所述激光器发射进入所述保偏光纤插针的激光。
  9. 根据权利要求1至8中任一项所述的相干接收装置，其中，所述混频器包括第一子混频器和第二子混频器；其中，
    所述第一子混频器，用于对所述第一信号光和所述本振光进行混频；
    所述第二子混频器，用于对所述第二信号光和所述本振光进行混频。
  10. 根据权利要求1至8中任一项所述的相干接收装置，其中，所述装置还包括：设置在所述混频器与所述PD阵列之间的反射棱镜和透镜阵列；其中，
    所述混频器输出的混频后的光经过所述反射棱镜反射以及所述透镜阵列汇聚后，再输出给所述PD阵列。
  11. 根据权利要求1至8中任一项所述的相干接收装置，其中，所述装置还包括：设置在所述偏振分束棱镜与所述混频器之间的两个C透镜；其中，
    所述偏振分束棱镜输出的所述第一信号光和所述第二信号光分别通过所述两个C透镜汇聚进入所述混频器。
  12. 一种测风激光雷达系统，包括：如权利要求1-11任一项所述的相干接收装置、激光单元和望远系统；其中，
    所述激光单元，用于发射激光，将所述激光分为第一部分激光以及第二部分激光；将所述第一部分激光输出给所述望远系统，以及将所述第二部分激光输出给所述相干接收装置；
    所述望远系统，用于将所述第一部分激光射入大气中，接收和大气中的气溶胶分子发生相互作用的回波信号，并将所述回波信号输出给所述相干接收装置；
    所述相干接收装置，用于接收所述第二部分激光作为本振光，将所述 本振光与所述回波信号进行干涉，形成解调信号，通过所述解调信号得到所述回波信号的多普勒频移量，根据所述多普勒频移量确定风速。
  13. 根据权利要求12所述的测风激光雷达系统，其中，所述激光单元包括：激光器和分束器；其中，
    所述激光器，用于发射激光；
    所述分束器，用于将所述激光分为具有第一能量的第一部分激光以及具有第二能量的第二部分激光，所述第一能量小于所述第二能量。
PCT/CN2020/135327 2020-11-11 2020-12-10 一种相干接收装置及测风激光雷达系统 WO2022099838A1 (zh)

Priority Applications (2)

Application Number Priority Date Filing Date Title
US18/252,355 US20240007194A1 (en) 2020-11-11 2020-12-10 Coherent receiving device and anemometry lidar system
EP20961392.6A EP4246835A4 (en) 2020-11-11 2020-12-10 COHERENT RECEIVING DEVICE AND ANEMOMETRY LIDAR SYSTEM

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN202011258199.XA CN112511239B (zh) 2020-11-11 2020-11-11 一种相干接收装置及测风激光雷达系统
CN202011258199.X 2020-11-11

Publications (1)

Publication Number Publication Date
WO2022099838A1 true WO2022099838A1 (zh) 2022-05-19

Family

ID=74957156

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2020/135327 WO2022099838A1 (zh) 2020-11-11 2020-12-10 一种相干接收装置及测风激光雷达系统

Country Status (4)

Country Link
US (1) US20240007194A1 (zh)
EP (1) EP4246835A4 (zh)
CN (1) CN112511239B (zh)
WO (1) WO2022099838A1 (zh)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115242314A (zh) * 2022-08-02 2022-10-25 北京中科国光量子科技有限公司 一种基于双向复用90°混频器的相干接收装置

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113702947A (zh) * 2021-08-09 2021-11-26 北京一径科技有限公司 一种跨阻放大器、光接收装置及激光雷达接收器
CN113885047B (zh) * 2021-08-23 2024-06-18 中国海洋大学 基于光学相干技术的双偏振高光谱分辨率激光雷达系统
CN113960631B (zh) * 2021-12-22 2022-04-08 青岛镭测创芯科技有限公司 一种雷达系统

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101825713A (zh) * 2009-12-24 2010-09-08 哈尔滨工业大学 一种2μm全光纤相干激光多普勒测风雷达系统
CN101825710A (zh) * 2009-12-24 2010-09-08 哈尔滨工业大学 一种2μm全光纤相干激光多普勒测风雷达系统
US7826752B1 (en) * 2005-06-02 2010-11-02 Level 3 Communications, Llc Optical transmission apparatuses, methods, and systems
CN106932785A (zh) * 2017-02-27 2017-07-07 南京红露麟激光雷达科技有限公司 一种时分复用的偏振相干多普勒测风激光雷达
CN106940444A (zh) * 2017-02-27 2017-07-11 南京红露麟激光雷达科技有限公司 基于微波差分增益的相干多普勒测风激光雷达
CN111525962A (zh) * 2019-02-02 2020-08-11 华为技术有限公司 相干光接收机、相干光处理方法和相干光接收设备

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7532311B2 (en) * 2005-04-06 2009-05-12 Lockheed Martin Coherent Technologies, Inc. Efficient lidar with flexible target interrogation pattern
JPWO2015190097A1 (ja) * 2014-06-12 2017-04-20 日本電気株式会社 光受信器及び光受信方法
US10114035B2 (en) * 2015-01-08 2018-10-30 Nec Corporation Remote wind turbulence sensing
CN111628827B (zh) * 2019-02-28 2022-05-06 华为技术有限公司 一种相干光学接收装置及光信号解调装置

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7826752B1 (en) * 2005-06-02 2010-11-02 Level 3 Communications, Llc Optical transmission apparatuses, methods, and systems
CN101825713A (zh) * 2009-12-24 2010-09-08 哈尔滨工业大学 一种2μm全光纤相干激光多普勒测风雷达系统
CN101825710A (zh) * 2009-12-24 2010-09-08 哈尔滨工业大学 一种2μm全光纤相干激光多普勒测风雷达系统
CN106932785A (zh) * 2017-02-27 2017-07-07 南京红露麟激光雷达科技有限公司 一种时分复用的偏振相干多普勒测风激光雷达
CN106940444A (zh) * 2017-02-27 2017-07-11 南京红露麟激光雷达科技有限公司 基于微波差分增益的相干多普勒测风激光雷达
CN111525962A (zh) * 2019-02-02 2020-08-11 华为技术有限公司 相干光接收机、相干光处理方法和相干光接收设备

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
PENG, CHENG: "Research on Dual-balanced Heterodyne Detection of 2μm Coherent Lidar for Wind Measurement", BASIC SCIENCES, CHINESE MASTER’S THESES FULL-TEXT DATABASE, no. 3, 15 March 2016 (2016-03-15), pages 1 - 61, XP055931131, ISSN: 1674-0246 *
See also references of EP4246835A4

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115242314A (zh) * 2022-08-02 2022-10-25 北京中科国光量子科技有限公司 一种基于双向复用90°混频器的相干接收装置

Also Published As

Publication number Publication date
CN112511239A (zh) 2021-03-16
EP4246835A1 (en) 2023-09-20
EP4246835A4 (en) 2024-10-02
CN112511239B (zh) 2022-03-11
US20240007194A1 (en) 2024-01-04

Similar Documents

Publication Publication Date Title
WO2022099838A1 (zh) 一种相干接收装置及测风激光雷达系统
US11268811B2 (en) Non-interferometric optical gyroscope based on polarization sensing
US10578740B2 (en) Coherent optical distance measurement apparatus and method
US11293757B2 (en) Non-interferometric optical gyroscope based on polarization sensing and implementations of closed loop control allowing for slow phase modulation
JP7402868B2 (ja) 走査ｌｉｄａｒにおけるデスキャン補正
WO2021012132A1 (zh) 一种激光雷达系统
US10310085B2 (en) Photonic integrated distance measuring pixel and method of distance measurement
US10429187B1 (en) Apparatus and method for optical power control
CN110890689A (zh) 一种同时实现激光器频率稳定和噪声抑制的反馈锁定结构
US8730481B2 (en) Sagnac optical ingredient-measuring apparatus with circular polarizers in parallel
CN109557557B (zh) 一种软件自定义多功能激光雷达
CN113960631B (zh) 一种雷达系统
CN113097842B (zh) 一种基于保偏光纤的超稳激光系统
CN101149263A (zh) 一种基于慢光效应的光学陀螺
JPH02118416A (ja) 光センサー装置
CN112147628B (zh) 基于光电振荡器的远距离位移测量装置和测量方法
CN216132474U (zh) 一种光纤光栅中心波长解调系统及解调仪
EP4279949A1 (en) Distance measuring
CN112129242B (zh) 基于光电振荡器的光纤扭转角度测量装置和方法
TW387055B (en) Distributed fiber grating sensing systems using birefringence fiber interferometers for detecting wavelength shifts
CN118566885A (zh) 一种鉴频器、驱动模块、探测设备以及鉴频方法
CN114812788A (zh) 一种低成本测振系统及方法
JP3339323B2 (ja) 光ファイバセンサ
JPS63157023A (ja) レ−ザ光のスペクトル線幅測定装置
JPS59217113A (ja) 光ヘテロダイン方式の光フアイバジヤイロ

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 20961392

Country of ref document: EP

Kind code of ref document: A1

WWE Wipo information: entry into national phase

Ref document number: 18252355

Country of ref document: US

NENP Non-entry into the national phase

Ref country code: DE

ENP Entry into the national phase

Ref document number: 2020961392

Country of ref document: EP

Effective date: 20230612