WO2023065327A1 - 探测系统和终端设备 - Google Patents

探测系统和终端设备 Download PDF

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Publication number
WO2023065327A1
WO2023065327A1 PCT/CN2021/125805 CN2021125805W WO2023065327A1 WO 2023065327 A1 WO2023065327 A1 WO 2023065327A1 CN 2021125805 W CN2021125805 W CN 2021125805W WO 2023065327 A1 WO2023065327 A1 WO 2023065327A1
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Prior art keywords
signal light
polarization
polarization state
light
processing
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PCT/CN2021/125805
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English (en)
French (fr)
Inventor
刘彤辉
李孟麟
巫红英
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华为技术有限公司
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Priority to PCT/CN2021/125805 priority Critical patent/WO2023065327A1/zh
Priority to CN202180103142.9A priority patent/CN118043701A/zh
Publication of WO2023065327A1 publication Critical patent/WO2023065327A1/zh

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    • 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
    • G01S17/06—Systems determining position data of a target

Definitions

  • the present application relates to the field of laser detection, in particular to a detection system and terminal equipment.
  • Lidar can be divided into direct detection lidar and coherent lidar according to the different detection methods used.
  • Direct detection lidar refers to the lidar that adopts direct detection method.
  • Coherent detection lidar refers to lidar that uses coherent detection.
  • the direct detection lidar obtains the round-trip distance by multiplying the time delay difference between the measured reflected and received light pulses by the speed of light, thereby obtaining distance information.
  • direct detection of lidar requires high-sensitivity detectors and high-peak power transmit pulse signals, which are greatly affected by noise.
  • coherent lidar uses continuous light as the detection signal, and obtains the frequency, amplitude, and phase information of the signal through the mixing of local oscillator light and signal light. It has high detection efficiency, anti-environmental light interference, and real-time velocity information. advantage.
  • crosstalk affects it more than direct detection lidar because of its advantage in detecting weak signals.
  • the level of control over crosstalk directly affects its detection capability and accuracy. Therefore, it is necessary to study how to reduce the influence of crosstalk in coherent detection.
  • the application discloses a detection system and terminal equipment, which can effectively reduce the influence of crosstalk in the detection system.
  • an embodiment of the present application provides a detection system, including: a beam splitting module, a polarization module, and a mixer; the beam splitting module is configured to perform beam splitting processing on the input signal light to obtain the first signal light and The second signal light; the polarization module, configured to output the transmitted signal light after at least first polarization processing is performed on the first signal light; and, obtain the reflected signal light of the transmitted signal light, and output the The reflected signal light is at least the third signal light after the second polarization processing; the mixer is configured to perform frequency mixing processing on the second signal light and the third signal light; The fourth signal light obtained after performing at least the third polarization processing on the second signal light and the third signal light are subjected to frequency mixing processing.
  • the polarizing module is configured to output the transmitted signal light after performing at least the first polarization processing on the first signal light, and output the third signal light after performing at least the second polarization processing on the reflected signal light.
  • the third signal light can be understood as the signal light after performing at least the first polarization processing and at least the second polarization processing on the first signal light. Only the third signal light and the crosstalk light whose polarization state is the same as that of the third signal light can be output to the mixer. Since crosstalk light whose polarization state is different from that of the third signal light cannot be output to the mixer, the influence of crosstalk can be effectively reduced. In addition, the polarization module itself brings less crosstalk.
  • the mixer is a polarization mixer, and the polarization states of the second signal light and the third signal light are orthogonal; or, the mixer is a non-polarization mixer frequency converter, the polarization state of the fourth signal light is the same as that of the third signal light.
  • the polarization module reduces the crosstalk caused by the reflected light, that is, the crosstalk light will not enter the mixer, so the mixer performs frequency mixing processing on the second signal light and the third signal light or performs a frequency mixing process on the third signal light Performing frequency mixing processing on the light and the fourth signal light can both improve the frequency mixing efficiency and reduce the influence of non-ideal factors such as depolarization.
  • the polarization module includes: a polarization conversion module and a unidirectional conduction device; the unidirectional conduction device is configured to output the first signal light to the polarization conversion module, and, used to output the third signal light to the mixer; the polarization conversion module is used to perform the first polarization processing on the first signal light; and is used to perform the first polarization processing on the reflected signal light The second polarization processing is performed.
  • the unidirectional conduction device is used to output the first signal light to the polarization conversion module, and output the third signal light to the mixer; leakage of part of the signal light to the mixer can be avoided.
  • the one-way conduction device is further configured to reflect, filter or absorb signal light of the first polarization state entering from a first direction, and the first direction is the third signal light input direction, the first polarization state is different from the polarization state of the third signal light.
  • the unidirectional conduction device is also used to reflect, filter or absorb the signal light of the first polarization state entering from the first direction, so that most of the crosstalk light will not enter the mixer; the crosstalk can be effectively reduced Influence.
  • the unidirectional conduction device is configured to reflect the third signal light from the first reflective surface to the mixer; and/or the unidirectional conduction device is configured to Reflecting the signal light of the first polarization state entering from the first direction from the second reflective surface; the first reflective surface is different from the second reflective surface, and the first polarization state is different from the first reflective surface The polarization states of the three signals.
  • the unidirectional conduction device is used to reflect the third signal light from the first reflective surface to the mixer; and/or the unidirectional conduction device is used to convert the first polarization state entering from the first direction
  • the signal light of the first polarization state is reflected from the second reflection surface; the signal light of the first polarization state can be prevented from entering the mixer, and the structure is simple.
  • the polarization conversion module includes: an optical antenna and a first polarization conversion device; the optical antenna is configured to output at least collimated signal light on the first signal light to The first polarization conversion device, and configured to output the third signal light to the unidirectional conduction device; the first polarization conversion device is configured to perform collimation processing on the first signal light The first polarization processing; and, for outputting the third signal light after performing the second polarization processing on the reflected signal light; or, the first polarization conversion device, for outputting the The fifth signal light after performing the first polarization processing on the first signal light is sent to the optical antenna; and, used to perform the second polarization processing on the reflected signal light; the optical antenna is used to output a pair of The fifth signal light is at least the transmitted signal light after performing collimation processing.
  • the optical antenna performs collimation processing on the signal light, so that the signal light can be coupled into the first polarization conversion device with the maximum efficiency or can be coupled and emitted with the maximum efficiency.
  • the beam splitting module includes: a beam splitter and a second polarization conversion device; the beam splitter is configured to perform beam splitting processing on the input signal light to obtain the first signal light and the second signal light; the second polarization conversion device, configured to output the fourth signal light obtained after performing at least the third polarization processing on the second signal light to the mixer.
  • the polarization state of the fourth signal light is orthogonal to the polarization state of the second signal light.
  • the second polarization conversion device is configured to output the fourth signal light obtained after performing at least the third polarization processing on the second signal light to the mixer, and can output the signal light of the required polarization state to the mixer. frequency converter.
  • the polarization state of the first signal light is the same as the polarization state of the second signal light.
  • the beam splitting module is a polarization beam splitter; the polarization state of the first signal light is orthogonal to the polarization state of the second signal light, and the signal input by the beam splitting module The polarization state of the light is not orthogonal to and not parallel to the polarization state of the first signal light.
  • the beam splitting module performs beam splitting processing on the input signal light to obtain the first signal light and the second signal light with orthogonal polarization states, which can ensure the polarization states of the local oscillator light and signal light input by the mixer In the same way, the frequency mixing efficiency can be improved, the structure is simple, and no additional polarization conversion device is required.
  • the beam splitter is a polarization beam splitter; the beam splitter is specifically configured to perform beam splitting processing and polarization state adjustment processing on the input signal light to obtain the first signal light and the second signal light; the polarization state of the first signal light is orthogonal to the polarization state of the second signal light, and the polarization state of the signal light input by the beam splitter is the same as that of the first signal light
  • the polarization states are not orthogonal and not parallel.
  • the beam splitting module performs beam splitting processing and polarization state adjustment processing on the input signal light to obtain the first signal light and the second signal light with orthogonal polarization states, which can ensure that the local oscillator light input by the mixer and The polarization states of the signal light are orthogonal for mixing processing using a polarization mixer.
  • the emitting optical path and the receiving optical path in the detection system are coaxially arranged.
  • an embodiment of the present application provides a laser radar system, including the detection system described in the above first aspect or any possible implementation manner of the above first aspect.
  • an embodiment of the present application provides a terminal device, including the detection system described in the foregoing first aspect or any possible implementation manner of the foregoing first aspect.
  • an embodiment of the present application provides a detection device, including at least one laser, at least one detector, and the detection system described in the above first aspect or any possible implementation manner of the above first aspect.
  • FIG. 1 is a schematic structural diagram of a detection system provided by an embodiment of the present application.
  • 2A to 2C are examples of the polarization state of the first signal light, the polarization state of the second signal light, and the polarization state of the third signal light provided in the embodiment of the present application;
  • 3A to 3D are examples of the polarization state of the first signal light, the polarization state of the second signal light, the polarization state of the third signal light, and the polarization state of the fourth signal light provided in the embodiment of the present application;
  • 4A to 4C are examples of the polarization state of the signal light input by the beam splitting module 10 provided by the embodiment of the present application, the polarization state of the first signal light, the polarization state of the second signal light, and the polarization state of the third signal light;
  • 5A to 5C are examples of the polarization state of the signal light input by the beam splitting module 10 provided by the embodiment of the present application, the polarization state of the first signal light, the polarization state of the second signal light, and the polarization state of the third signal light;
  • FIG. 6 is a schematic structural diagram of a polarization module provided in an embodiment of the present application.
  • FIG. 7 is an example of processing the third signal light entering from the first direction and the signal light of the first polarization state by a unidirectional conduction device provided by the embodiment of the present application;
  • FIG. 8A and FIG. 8B are schematic structural diagrams of the polarization conversion module 602 provided by the embodiment of the present application.
  • FIG. 9 is a schematic structural diagram of a beam splitting module 10 provided in an embodiment of the present application.
  • Fig. 10 is an example of a coaxial arrangement of the transmitting optical path and the receiving optical path provided by the embodiment of the present application;
  • Fig. 11 is a schematic structural diagram of another detection system provided by the embodiment of the present application.
  • Fig. 12 is a schematic structural diagram of another detection system provided by the embodiment of the present application.
  • Fig. 13 is a schematic structural diagram of another detection system provided by the embodiment of the present application.
  • FIG. 14 is a schematic structural diagram of another detection system provided by the embodiment of the present application.
  • FIG. 15A and FIG. 15B are examples of test results of a coaxial transceiving detection system using a non-polarizing device (circulator) as a non-reciprocal device;
  • 16A and 16B are examples of test results of a coaxial transceiving detection system using a polarizing device as a non-reciprocal device.
  • the present application provides a detection system capable of effectively reducing crosstalk effects.
  • the detection system provided by the present application can also reduce the crosstalk caused by the device itself.
  • lidar In order to make it easier to understand the lidar provided by this application, some knowledge related to lidar is introduced below.
  • two basic optical systems can be included-coaxial and paraxial optical systems.
  • the axis where the emitting beam is located and the axis where the receiving optical path is located are located or partly located on the same optical axis.
  • the structure is simple and the transmission and reception efficiency is high, but it is easily affected by near-field backscattered light.
  • the paraxial (also known as dual-axis) optical system the laser beam is separated from the optical axis of the receiver, and the emitted beam can only coincide with the receiving field of view within a certain range. Rangefinder systems are less susceptible to near-field backscatter, but have close-range blind spots.
  • the reflected light passing through the device will introduce a signal much larger than the target reflected light (that is, the required signal light), which will greatly affect the detection of short-distance signals after mixing with the local oscillator light , and raise the noise level at long distances.
  • the influence of crosstalk is more serious.
  • FIG. 1 is a schematic structural diagram of a detection system provided by an embodiment of the present application.
  • the detection system includes: a beam splitting module 10 , a polarization module 20 and a mixer 40 .
  • the functions of the beam splitting module 10, the polarization module 20 and the mixer 40 are as follows:
  • a beam splitting module 10 configured to perform beam splitting processing on the input signal light to obtain first signal light and second signal light;
  • Polarization module 20 configured to output the transmitted signal light after performing at least the first polarization processing on the above-mentioned first signal light; and acquire (or receive) the reflected signal light of the above-mentioned transmitted signal light, and output at least The third signal light after the second polarization processing is sent to the mixer 40;
  • the mixer 40 is configured to perform frequency mixing processing on the above-mentioned second signal light and the above-mentioned third signal light; or is used to perform at least third polarization processing on the above-mentioned second signal light to obtain the fourth signal light and The above-mentioned third signal light performs frequency mixing processing.
  • the beam splitting module 10 is also used to output the first signal light to the polarization module 20, and output the second signal light to the mixer 40; the polarization state of the third signal light and the polarization state of the second signal light
  • the states are orthogonal, and the mixer 40 is a polarization mixer.
  • the polarization state of the second signal light is the same as that of the first signal light, for example, both are horizontally polarized or vertically polarized; the polarization state of the third signal light is the same as the polarization state of the first signal light Orthogonal.
  • FIG. 2A to 2C are examples of the polarization state of the first signal light, the polarization state of the second signal light, and the polarization state of the third signal light provided in the embodiment of the present application.
  • 201 represents the polarization state of the first signal light
  • 202 represents the polarization state of the second signal light
  • 203 represents the polarization state of the third signal light; wherein, the polarization state of the second signal light and the polarization state of the first signal light The same (both are horizontally polarized), the polarization state of the third signal light is orthogonal to the polarization state of the first signal light, and the polarization state of the third signal light is orthogonal to that of the second signal light.
  • Fig. 2A 201 represents the polarization state of the first signal light
  • 202 represents the polarization state of the second signal light
  • 203 represents the polarization state of the third signal light
  • the polarization state of the third signal light is orthogonal to the polarization state
  • 204 represents the polarization state of the first signal light
  • 205 represents the polarization state of the second signal light
  • 206 represents the polarization state of the third signal light; wherein, the polarization state of the second signal light and the polarization state of the first signal light
  • the polarization state of the third signal light is orthogonal to that of the first signal light
  • the polarization state of the third signal light is orthogonal to that of the second signal light.
  • 207 represents the polarization state of the first signal light
  • 208 represents the polarization state of the second signal light
  • 209 represents the polarization state of the third signal light; wherein, the polarization state of the second signal light and the polarization state of the first signal light
  • the polarization state of the third signal light is orthogonal to that of the first signal light
  • the polarization state of the third signal light is orthogonal to that of the second signal light.
  • the beam splitting module 10 is further configured to output the first signal light to the polarization module 20, and output the fourth signal light obtained after performing at least the third polarization processing on the second signal light to the mixer 40;
  • the polarization state of the fourth signal light is the same as that of the third signal light, and the mixer 40 is a non-polarization mixer.
  • the polarization state of the first signal light and the polarization state of the second signal light are the same, for example, both are horizontally polarized or vertically polarized; the polarization state of the third signal light is the same as the polarization state of the first signal light Orthogonal, the polarization state of the third signal light is orthogonal to the polarization state of the second signal light, and the polarization state of the second signal light is orthogonal to the polarization state of the fourth signal light.
  • the beam splitting module 10 performs at least the third polarization processing on the second signal light, which may be to perform polarization transformation on the second signal light, for example, transforming the second signal light from polarization state 1 to polarization state 2, where polarization state 1 and polarization state 2 are positive pay.
  • the beam splitting module 10 transforms the second signal light from horizontal polarization to vertical polarization to obtain fourth signal light.
  • the polarization state of the first signal light and the polarization state of the second signal light are the same or different, the polarization state of the second signal light and the polarization state of the fourth signal light are not orthogonal and not parallel,
  • the polarization state of the third signal light and the polarization state of the first signal light are not orthogonal and not parallel.
  • it is only necessary to ensure that the polarization state of the third signal light and the polarization state of the fourth signal light are orthogonal, and the polarization state of the first signal light, the polarization state of the second signal light or the polarization state of the third signal light may not be adjusted.
  • the polarization state is limited.
  • the polarization state of the first signal light is the same as that of the second signal light
  • the polarization state of the second signal light is 45 degrees to the polarization state of the fourth signal light
  • the polarization state of the third signal light is the same as that of the first signal light.
  • the polarization state of the signal light is 45 degrees
  • the polarization state of the fourth signal light is the same as that of the third signal light.
  • the polarization state of the first signal light is 90 degrees to the polarization state of the second signal light
  • the polarization state of the second signal light is 45 degrees to the polarization state of the fourth signal light
  • the polarization state of the third signal light is The polarization state of the first signal light is 45 degrees
  • the polarization state of the fourth signal light is the same as that of the third signal light.
  • 3A to 3D are examples of the polarization state of the first signal light, the polarization state of the second signal light, the polarization state of the third signal light and the polarization state of the fourth signal light provided by the embodiment of the present application.
  • 301 represents the polarization state of the first signal light
  • 302 represents the polarization state of the second signal light
  • 303 represents the polarization state of the third signal light
  • 304 represents the polarization state of the fourth signal light;
  • the first signal light The polarization state of the second signal light is the same as that of the second signal light (both are horizontally polarized)
  • the polarization state of the third signal light is orthogonal to that of the first signal light
  • the polarization state of the fourth signal light is orthogonal to that of the second signal light
  • the polarization states are orthogonal
  • the polarization state of the fourth signal light is the same as that of the third signal light.
  • 305 represents the polarization state of the first signal light
  • 306 represents the polarization state of the second signal light
  • 307 represents the polarization state of the third signal light
  • 308 represents the polarization state of the fourth signal light
  • the first signal light The polarization state of the second signal light is the same as the polarization state of the second signal light (both are vertically polarized)
  • the polarization state of the third signal light is orthogonal to the polarization state of the first signal light
  • the polarization state of the fourth signal light is orthogonal to that of the second signal light
  • the polarization states are orthogonal
  • the polarization state of the fourth signal light is the same as that of the third signal light.
  • 3C 309 represents the polarization state of the first signal light
  • 310 represents the polarization state of the second signal light
  • 311 represents the polarization state of the third signal light
  • 312 represents the polarization state of the fourth signal light
  • the first signal light The polarization state of the second signal light is the same as the polarization state of the second signal light (vertical polarization)
  • the polarization state of the third signal light is 45 degrees to the polarization state of the first signal light (can be other angles)
  • the polarization state of the second signal light is 45 degrees (can be other angles)
  • the polarization state of the fourth signal light is the same as that of the third signal light.
  • 3D 313 represents the polarization state of the first signal light
  • 314 represents the polarization state of the second signal light
  • 315 represents the polarization state of the third signal light
  • 316 represents the polarization state of the fourth signal light
  • the first signal light The polarization state of the second signal light is the same as that of the second signal light (non-vertical polarization or horizontal polarization)
  • the polarization state of the third signal light is orthogonal to that of the first signal light
  • the polarization state of the fourth signal light is orthogonal to that of the second signal light
  • the polarization states of the light are orthogonal
  • the polarization state of the fourth signal light is the same as that of the third signal light.
  • the beam splitting module 10 is also used to output the first signal light to the polarization module 20, and output the second signal light to the mixer 40; the polarization state of the first signal light and the polarization state of the second signal light
  • the polarization state of the signal light input by the beam splitting module 10 is not orthogonal to and not parallel to the polarization state of the first signal light (or the second signal light), and the polarization state of the second signal light and the polarization state of the third signal light
  • the polarization states are the same, and the mixer 40 is a non-polarization mixer.
  • the polarization state of the third signal light is orthogonal to the polarization state of the first signal light, for example, both are horizontally polarized or vertically polarized.
  • 4A to 4C are examples of the polarization state of the signal light input by the beam splitting module 10 provided by the embodiment of the present application, the polarization state of the first signal light, the polarization state of the second signal light, and the polarization state of the third signal light.
  • Fig. 1 the polarization state of the signal light input by the beam splitting module 10 provided by the embodiment of the present application, the polarization state of the first signal light, the polarization state of the second signal light, and the polarization state of the third signal light.
  • 401 represents the polarization state of the signal light input by the beam splitting module 10 (that is, the input signal light of the beam splitting module), 402 represents the polarization state (vertical polarization) of the first signal light, and 403 represents the polarization of the second signal light state (horizontal polarization), 404 represents the polarization state of the third signal light; wherein, the polarization state of the first signal light and the polarization state of the second signal light are orthogonal, and the polarization state of the third signal light and the polarization state of the first signal light The states are orthogonal, and the polarization state of the second signal light is the same as that of the third signal light.
  • 405 represents the polarization state of the signal light input by the beam splitting module 10 (i.e. the input signal light of the beam splitting module)
  • 406 represents the polarization state (horizontal polarization) of the first signal light
  • 407 represents the polarization of the second signal light state (vertical polarization)
  • 408 represents the polarization state of the third signal light; wherein, the polarization state of the first signal light and the polarization state of the second signal light are orthogonal, and the polarization state of the third signal light and the polarization state of the first signal light The states are orthogonal, and the polarization state of the second signal light is the same as that of the third signal light.
  • 409 represents the polarization state (for example, horizontal polarization) of the signal light input by the beam splitting module 10 (ie, the input signal light of the beam splitting module), and 410 represents the polarization state (non-vertical polarization or horizontal polarization) of the first signal light
  • 411 represents the polarization state of the second signal light
  • 412 represents the polarization state of the third signal light; wherein, the polarization state of the first signal light and the polarization state of the second signal light are orthogonal, and the polarization state of the third signal light and the polarization state of the first signal light
  • the polarization state of the first signal light is orthogonal, and the polarization state of the second signal light is the same as that of the third signal light.
  • the polarization angle between the input signal light of the beam splitting module and the first signal light may be 45 degrees or other angles, which is not limited in this embodiment of the present application.
  • the beam splitting module 10 is further configured to output the first signal light to the polarization module 20, and output the fourth signal light obtained after performing at least the third polarization processing on the second signal light to the mixer 40;
  • the polarization state of the fourth signal light is orthogonal to the polarization state of the third signal light, and the mixer 40 is a polarization mixer.
  • the polarization state of the first signal light and the polarization state of the second signal light are orthogonal, and the polarization state of the signal light input by the beam splitting module 10 and the polarization state of the first signal light (or the second signal light) Non-orthogonal and non-parallel, the polarization state of the second signal light is orthogonal to the polarization state of the fourth signal light, and the polarization state of the third signal light is orthogonal to the polarization state of the first signal light.
  • 5A to 5C show the polarization state of the signal light input by the beam splitting module 10 provided by the embodiment of the present application, the polarization state of the first signal light, the polarization state of the second signal light, the polarization state of the third signal light, and the fourth polarization state of the signal light.
  • 501 represents the polarization state of the signal light input by the beam splitting module 10 (that is, the input signal light of the beam splitting module), 502 represents the polarization state (vertical polarization) of the first signal light, and 503 represents the polarization of the second signal light state (horizontal polarization), 504 represents the polarization state of the third signal light, and 505 represents the polarization state of the fourth signal light; wherein, the polarization state of the first signal light is orthogonal to the polarization state of the second signal light, and the third signal light The polarization state of the first signal light is orthogonal to that of the first signal light, and the polarization state of the fourth signal light is orthogonal to that of the second signal light.
  • 506 represents the polarization state of the signal light input by the beam splitting module 10 (that is, the input signal light of the beam splitting module), 507 represents the polarization state (horizontal polarization) of the first signal light, and 508 represents the polarization of the second signal light state (vertical polarization), 509 represents the polarization state of the third signal light, and 510 represents the polarization state of the fourth signal light; wherein, the polarization state of the first signal light is orthogonal to the polarization state of the second signal light, and the third signal light The polarization state of the first signal light is orthogonal to that of the first signal light, and the polarization state of the fourth signal light is orthogonal to that of the second signal light.
  • the polarization state of the first signal light is orthogonal to that of the first signal light
  • the polarization state of the fourth signal light is orthogonal to that of the second signal light.
  • 511 represents the polarization state (for example, horizontal polarization) of the signal light input by the beam splitting module 10 (ie, the input signal light of the beam splitting module), and 512 represents the polarization state (non-vertical polarization or horizontal polarization) of the first signal light
  • 513 represents the polarization state of the second signal light
  • 514 represents the polarization state of the third signal light
  • 515 represents the polarization state of the fourth signal light
  • the polarization state of the first signal light and the polarization state of the second signal light are orthogonal
  • the polarization state of the third signal light is orthogonal to the polarization state of the first signal light
  • the polarization state of the fourth signal light is orthogonal to that of the second signal light.
  • both the first signal light and the third signal light are linearly polarized light
  • the transmitted signal light after performing at least the first polarization processing on the first signal light and the reflected signal light of the transmitted signal light are both circularly polarized light or elliptically polarized light.
  • the fourth signal light may be linearly polarized light.
  • the polarization module has a polarization selection function, that is, only the signal light of a specific polarization state (such as the third signal light) is output to the mixer, and the signal light of other polarization states is not output to the mixer. function.
  • the polarization module is used to output the transmitted signal light after performing at least the first polarization processing on the first signal light; and, acquire (or receive) the reflected signal light of the transmitted signal light, and output the The reflected signal light is sent to the mixer 40 as the third signal light after performing at least the second polarization processing. Since the crosstalk light whose polarization state is different from that of the third signal light cannot be output to the mixer, the influence of crosstalk of reflected light can be effectively reduced.
  • the polarization module only outputs signal light of a certain polarization state to the mixer.
  • the crosstalk light of other polarization states cannot enter the mixer, that is, most of the crosstalk light cannot enter the mixer, so the influence of crosstalk can be effectively reduced.
  • FIG. 6 is a schematic structural diagram of a polarization module provided by an embodiment of the present application.
  • the polarization module 20 includes: a unidirectional conduction device 601 and a polarization conversion module 602 .
  • the functions of the unidirectional conduction device 601 and the polarization conversion module 602 are as follows:
  • a unidirectional conduction device 601 configured to output the first signal light to the polarization conversion module, and used to output the third signal light to the mixer 40;
  • the polarization conversion module 602 is configured to perform first polarization processing on the first signal light; and is configured to perform second polarization processing on the reflected signal light.
  • the polarization conversion module 602 is further configured to output the transmitted signal light after performing the first polarization processing on the first signal light, and output the third signal light after performing the second polarization processing on the reflected signal light to the unidirectional conducting device 601 .
  • the polarization conversion module 602 is also configured to receive reflected signal light.
  • the one-way conduction device 601 may be a one-way conduction non-reciprocal device.
  • the signal light entering the one-way conducting device 601 from the first direction is all emitted, filtered or absorbed, that is, it cannot pass through the one-way conducting device 601; the signal light entering the one-way conducting device 601 from the second direction can pass through the one-way conducting device 601 .
  • the unidirectional conduction device 601 includes two input ends, the signal light input from one input end (corresponding to the first direction) is all emitted, filtered or absorbed, and the signal light input from the other input end (corresponding to the second direction) The input signal light passes through the unidirectional conduction device 601 and is output from its output terminal.
  • the first signal light enters the unidirectional conduction device 601 from the second direction, and the unidirectional conduction device 601 outputs the first signal light to the polarization transformation module 602; the third signal light enters the unidirectional conduction device from the first direction
  • the device 601 , the unidirectional conduction device 601 inputs the third signal light to the mixer 40 .
  • the one-way conduction device 601 is also used to reflect, filter or absorb the signal light of the first polarization state entering from the first direction, the first direction is the input direction of the third signal light, and the first polarization state is different from the above The polarization state of the third signal light.
  • the signal light of the first polarization state entering the unidirectional conducting device 601 from the first direction is reflected, filtered or absorbed by the unidirectional conducting device 601 , that is, the signal light of the first polarization state will not be output to the mixer.
  • the unidirectional conduction device 601 has the function of polarized light selection, that is, the signal light of the second polarization state (for example, the third signal light) entering from the first direction is output to the mixer, and the first polarization state entering from the first direction is output to the mixer.
  • the signal light of the polarization state is reflected, filtered or absorbed.
  • the first polarization state refers to any polarization state different from the second polarization state.
  • the unidirectional conduction device 601 only outputs the signal light of the second polarization state (such as the third signal light) entering from the first direction to the mixer, and the other polarization states entering from the first direction (any different from The signal light of the polarization state of the second polarization state) cannot be output to the mixer.
  • the unidirectional conduction device 601 is configured to reflect the third signal light from the first reflective surface to the mixer; reflect the signal light of the first polarization state entering from the first direction from the second reflective surface; The first reflection surface is different from the second reflection surface, and the first polarization state is different from the polarization state of the third signal.
  • the unidirectional conduction device 601 may be a polarization beam splitter or a polarization selection device, such as a polarization beam splitter (polarization beam splitter, PBS).
  • FIG. 7 is an example of processing a third signal light entering from a first direction and a signal light of a first polarization state by a unidirectional conduction device provided by an embodiment of the present application. As shown in Figure 7, the third signal light that enters the unidirectional conduction device 601 from the first direction is reflected to the mixer from the first reflective surface (the upper reflective surface in the figure); enters the unidirectional conduction device 601 from the first direction The signal light of the first polarization state is reflected from the second reflective surface.
  • the polarization conversion module 602 is configured to output the transmitted signal light after performing at least the first polarization processing on the first signal light, and receive the reflected signal light of the transmitted signal light, and output the reflected signal light after performing at least the second polarization processing on the reflected signal light The third signal light. It can be seen that the polarization conversion module 602 performs at least the first polarization processing on the first signal light and at least the second polarization processing on the reflected signal light to obtain the third signal light that can be output to the mixer by the unidirectional conducting device 601 .
  • the unidirectional conduction device 601 has a polarization selection function, that is, outputting the third signal light entering from the first direction to the mixer, and reflecting, filtering or absorbing the signal light of the first polarization state entering from the second direction. In this way, only the third signal light (the required target emission light) will be output to the mixer by the unidirectional conduction device 601, and the crosstalk light will not be output to the mixer, so the influence of crosstalk can be effectively reduced.
  • FIG. 8A and FIG. 8B are schematic structural diagrams of the polarization conversion module 602 provided by the embodiment of the present application.
  • the polarization conversion module 602 includes: an optical antenna 6021 and a first polarization conversion device 6022 ; wherein, the first signal light output by the unidirectional conduction device 601 enters the optical antenna.
  • the functions of the optical antenna 6021 and the first polarization conversion device 6022 are as follows:
  • An optical antenna 6021 configured to output at least collimated signal light for the first signal light to the first polarization conversion device, and for outputting the third signal light to the unidirectional conduction device;
  • the first polarization conversion device 6022 is configured to perform the first polarization processing on the collimated first signal light; and is configured to output the third signal light after performing the second polarization processing on the reflected signal light.
  • the first polarization conversion device 6022 can also be used to receive reflected signal light and output the third signal light to the optical antenna 6021 .
  • the first polarization conversion device 6022 may also be configured to output the transmitted signal light after the first polarization processing is performed on the collimated first signal light.
  • the optical antenna 6021 may include a collimator.
  • the optical antenna 6021 includes a lens composed of one or more lenses.
  • the optical antenna 6021 can collimate the first signal light, that is, collimate the input light beam.
  • the first polarization conversion device 6022 can be a quarter wave plate or others.
  • the first polarization conversion device 6022 has the following characteristics: a light beam (any linearly polarized light) can be converted from linearly polarized light (such as the first signal light) once (or once) through the first polarization conversion device 6022 The circularly polarized or elliptically polarized light passes through the first polarization conversion device 6022 twice (outgoing light and returning light), so that the light beam can be converted from one polarization state to another polarization state orthogonal to it.
  • a light beam any linearly polarized light
  • linearly polarized light such as the first signal light
  • the circularly polarized or elliptically polarized light passes through the first polarization conversion device 6022 twice (outgoing light and returning light), so that the light beam can be converted from one polarization state to another polarization state orthogonal to it.
  • the third signal light can be regarded as the signal light obtained by the first signal light passing through the first polarization conversion device 6022 twice, once the first polarization conversion device 6022 performs the first polarization processing on the collimated first signal light
  • the transmitted signal light is output, and the second polarization is performed on the reflected signal light to output the third signal light.
  • the polarization state of the transmitted signal light is the same as that of the reflected signal light.
  • the polarization conversion module 602 includes: a first polarization conversion device 6023 and an optical antenna 6024 ; wherein, the first signal light output by the unidirectional conduction device 601 enters the first polarization conversion device 6023 .
  • the functions of the first polarization conversion device 6023 and the optical antenna 6024 are as follows:
  • the first polarization conversion device 6023 is configured to output the fifth signal light after performing the first polarization processing on the first signal light to the optical antenna 6024; and is used to perform the second polarization processing on the reflected signal light;
  • the optical antenna 6024 is configured to output the above-mentioned transmitted signal light after performing at least collimation processing on the above-mentioned fifth signal light.
  • the optical antenna 6024 can also be used to receive reflected signal light, and output the reflected signal light to the first polarization conversion device 6023 .
  • the first polarization conversion device 6023 may be configured to output the third signal light after performing the second polarization processing on the reflected signal light to the one-way conducting device 601 .
  • Optical antenna 6024 may include a collimator.
  • the optical antenna 6024 is a lens composed of one or more lenses.
  • the optical antenna 6024 can collimate the fifth signal light, that is, collimate the input light beam.
  • the first polarization conversion device 6023 can be a quarter wave plate or others.
  • the first polarization conversion device 6023 has the following characteristics: the light beam (arbitrary linearly polarized light) can be converted from linearly polarized light (such as the first signal light) once (or once) through the first polarization conversion device 6023 If the light is circularly polarized or elliptically polarized, it passes through the first polarization conversion device 6023 twice (outgoing light and returning light), so that the light beam can be converted from one polarization state to another polarization state orthogonal to it.
  • the light beam arbitrary linearly polarized light
  • linearly polarized light such as the first signal light
  • the third signal light can be regarded as the signal light obtained by the first signal light passing through the first polarization conversion device 6023 twice, once the first polarization conversion device 6023 performs the first polarization processing on the first signal light to output the fifth signal light, Once, the second polarization is performed on the reflected signal light to output the third signal light.
  • the polarization state of the transmitted signal light is the same as that of the reflected signal light.
  • the function of the optical antenna in the polarization conversion module 602 is to couple the signal light into the desired device with maximum efficiency.
  • the optical antenna 6024 performs collimation processing on the signal light, so that the signal light can be coupled into the first polarization conversion device 6023 with the maximum efficiency or can be coupled and emitted out of the detection system with the maximum efficiency.
  • FIG. 9 is a schematic structural diagram of a beam splitting module 10 provided in an embodiment of the present application.
  • the beam splitting module 10 includes: a beam splitter 101 and a second polarization conversion device 102 .
  • a beam splitter 101 configured to perform beam splitting processing on input signal light to obtain first signal light and second signal light;
  • the second polarization conversion device 102 is configured to output the fourth signal light obtained after performing at least the third polarization processing on the second signal light to the mixer.
  • the polarization state of the first signal light is the same as that of the second signal light, and the polarization state of the fourth signal light is orthogonal to that of the second signal light.
  • the beam splitter 101 is specifically used to perform beam splitting processing on the input signal light to obtain the first signal light and the second signal light, output the first signal light to the polarization module 20 and output the second signal light to the second polarization transformation Device 102 . It should be understood that the beam splitter 101 splits the incident light according to a certain ratio, one path enters the polarization module 20 as signal light, and the other path enters the second polarization conversion device 102 as local oscillator light.
  • the splitting ratio of the beam splitter 101 can be configured according to actual needs, that is, the ratio of signal light and the ratio of local oscillator light.
  • the function of the second polarization conversion device 102 is to perform polarization conversion on the input signal light (for example, the second signal light).
  • the second polarization conversion device 102 is used to convert the polarization state of the second signal light (local oscillator light), for example, convert the polarization state of the second signal light (ie, local oscillator light) by 90 degrees.
  • the second polarization conversion device 102 converts the second signal light from horizontal polarization to vertical polarization to obtain fourth signal light.
  • the second polarization conversion device 102 may be a half-wave plate or others.
  • the second polarization conversion device 102 is configured to output the fourth signal light obtained after performing at least the above-mentioned third polarization processing on the second signal light to the mixer, so that the mixer can perform the local oscillator light (that is, the first Four signal lights) and the third signal light are mixed.
  • the beam splitter 101 is a polarization beam splitter, the polarization state of the first signal light is orthogonal to the polarization state of the second signal light, and the polarization state of the signal light input by the beam splitter 101 is the same as that of the first signal light
  • the polarization states of are not orthogonal and not parallel.
  • the beam splitter 101 can be used to perform beam splitting and polarization adjustment processing on the input signal light (for example, adjust the polarization state of the signal light) to obtain the first signal light and the second signal light, and output the first signal light to the polarization module 20 and output the second signal light to the second polarization conversion device 102 .
  • the vertical polarization can be defined as polarization state 1
  • the horizontal polarization can be defined as polarization state 2.
  • the polarization state of the optical signal incident on the beam splitter 101 is the polarization state 3 which forms a certain angle (for example, 1°-89°) with the polarization state 1 and the polarization state 2 respectively.
  • the beam splitter 101 can adjust the signal path (corresponding to the signal light) and the local oscillator path (corresponding to the local oscillator light) based on the specific angles presented by the polarization state 3 and the polarization state 1 and the polarization state 2. ) splitting ratio to realize the function of the beam splitter.
  • the beam splitter 101 adjusts the specific angle of the polarization state 3 (that is, the polarization state adjustment process), so that a large proportion of light enters the polarization module 20 in the state of polarization state 1 (corresponding to the first signal light) as signal light;
  • a small proportion of light enters the second polarization conversion device 102 in the state of polarization state 2 (corresponding to the second signal light) as local oscillator light.
  • the second polarization conversion device 102 is configured to output the fourth signal light obtained after performing at least the third polarization processing on the second signal light to the mixer.
  • the beam splitter 101 performs beam splitting processing and polarization adjustment processing on the input signal light to obtain the first signal light and the second signal light with orthogonal polarization states, and the output of the second polarization conversion device 102 is opposite to the second signal light.
  • the fourth signal light obtained after performing at least the third polarization processing on the signal light is sent to the mixer, so that the polarization states of the local oscillator light input by the mixer and the signal light are orthogonal.
  • the beam splitter 101 in the beam splitting module 10 is a polarization beam splitter, so that the polarization states of the local oscillator light and the signal light input by the mixer are orthogonal .
  • the beam splitting module 10 is a beam splitter, and the polarization state of the first signal light is the same as that of the second signal light.
  • the beam splitting module 10 is specifically configured to perform beam splitting processing on the input signal light to obtain the first signal light and the second signal light, output the first signal light to the polarization module 20 and output the second signal light to the mixer 40 .
  • the beam splitter 101 can split the incident light according to a certain ratio, one path enters the polarization module 20 as signal light, and the other path enters the mixer as local oscillator light.
  • the splitting ratio of the beam splitting module 10 can be configured according to actual needs, that is, the ratio of the signal light to the local oscillator light.
  • the beam splitting module 10 only needs to perform beam splitting processing on the input signal light to obtain the first signal light and the second signal light, which has a simple structure and low cost.
  • the beam splitting module 10 is a polarization beam splitter, the polarization state of the first signal light is orthogonal to the polarization state of the second signal light, and the polarization state of the signal light input by the beam splitting module 10 is the same as that of the first signal light
  • the polarization states of are not orthogonal and not parallel. Assuming that the transmission direction of light is to propagate toward the paper surface, the vertical polarization can be defined as polarization state 1, and the horizontal polarization can be defined as polarization state 2.
  • the polarization state of the optical signal incident on the beam splitting module 10 is the polarization state 3 which forms a certain angle (for example, 1°-89°) with the polarization state 1 and the polarization state 2 respectively.
  • the splitting ratio of the signal path (corresponding to signal light) and the local oscillator path (corresponding to local oscillator light) can be adjusted based on the specific angles presented by polarization state 3, polarization state 1, and polarization state 2 , to realize the function of the beam splitter. For example, by adjusting the specific angle of polarization state 3, a large proportion of light is used as signal light and enters the polarization module 20 in the state of polarization state 1; by adjusting the specific angle of polarization state 3, a small proportion of light is used as local oscillator light, Enters mixer 40 with polarization state 2.
  • the large ratio may be a light splitting ratio above 90%, and the small ratio may be a light splitting ratio below 10%.
  • the beam splitting module 10 performs beam splitting processing on the input signal light to obtain the first signal light and the second signal light with orthogonal polarization states, which can ensure the polarization of the local oscillator light and signal light input by the mixer The state is the same, which can improve the mixing efficiency.
  • the emitting light path and receiving light path in the detection system provided by the present application can be coaxially arranged.
  • the case where the transmitting optical path and the receiving optical path are coaxially arranged is called a coaxial optical system.
  • the advantage of the coaxial optical system is its simple structure and high transceiving efficiency, but it is easily affected by crosstalk and stray light.
  • the detection system in these embodiments has simple structure, high transceiving efficiency, and is not easily affected by crosstalk and stray light.
  • FIG. 10 is an example of a detection system provided by an embodiment of the present application in which the emitting optical path and the receiving optical path are coaxially arranged. As shown in FIG.
  • 1001 denotes an emitting light source
  • 1002 denotes a collimating optical path
  • 1003 denotes a spectroscopic device
  • 1004 denotes a scanning mechanism
  • 1005 denotes an object
  • 1006 denotes a focusing lens
  • 1007 denotes a detector.
  • the signal light emitted by the emitting light source passes through the collimated optical path 1002 (or called a collimator), the spectroscopic device 1003, and the scanning mechanism 1004 to reach the target in sequence;
  • the signal light reflected by the target passes through the scanning mechanism 1004 in sequence , the spectroscopic device 1003 , the focusing lens 1006 reaches the detector 1007 .
  • the transmitting optical path refers to the optical path from the generation of the emitting light (that is, the signal light emitted by the emitting light source) to the emission of the emitting light through the optical splitting device 1003, and the receiving optical path refers to receiving the reflected light from the scanning mechanism 1004 to the Light path transmitted to detector 1007.
  • the solid line arrows indicate the transmitting optical path
  • the dashed line arrows indicate the receiving optical path. It can be seen from FIG. 10 that the transmitting optical path and the receiving optical path can be coaxially arranged.
  • the detection system in FIG. 10 may be a laser radar system
  • the emitting light source 1001 may be a laser
  • the detector 1007 may be a PIN detector, an APD detector, a balance detector, and the like.
  • FIG. 11 is a schematic structural diagram of another detection system provided by an embodiment of the present application.
  • the detection system in FIG. 11 is a possible implementation of the detection system in FIG. 1 .
  • the detection system includes: a signal generator 1101, a laser 1102, an amplifier 1103, a beam splitter 101, a second polarization conversion device 102, a unidirectional conduction device 601, an optical antenna 6021, a first polarization conversion device 6022, Mixer 40, detector 1104, analog to digital converter (analog to digital converter, ADC) 1105, processing unit 1106.
  • ADC analog to digital converter
  • a possible structure of the beam splitting module 10 includes: a beam splitter 101 and a second polarization conversion device 102 .
  • the one-way conducting device 601 , the optical antenna 6021 and the first polarization conversion device 6022 correspond to the polarization module 20 .
  • a possible structure of the polarization module 20 includes: a unidirectional conduction device 601 , an optical antenna 6021 and a first polarization conversion device 6022 .
  • any one or more devices in Figure 11 can be reduced or replaced, and it can also be understood that in a specific implementation, the detection system can include all of the devices shown in Figure 11 One or more of the devices, the present application does not specifically limit the structural composition of the detection system.
  • An exemplary description of the functions of each device in Figure 11 is as follows:
  • the signal generator 1101 is used for modulating the laser 1102 .
  • the modulation method of the laser 1102 can be direct modulation or external modulation through a modulator, and the modulation method can be frequency modulated continuous wave, phase encoding or others.
  • the structure in which the signal generator 1101 modulates the laser 1102 can be replaced by: the laser signal output by the laser 1102 enters the modulator; the modulator modulates the input laser signal, and outputs the modulated laser signal to Amplifier 1103.
  • the modulator modulates the laser signal output by the laser 1102 according to the modulation signal input by the signal generator. That is, in some scenarios, the signal generator is optional.
  • the laser 1102 is used to output the laser signal into the amplifier 1103 .
  • Laser 1102 may be a narrow linewidth laser, such as a semiconductor laser, fiber laser, or other type of laser.
  • the amplifier 1103 is used to amplify the input laser signal, and output the amplified laser signal to the beam splitter 101 .
  • the amplifier 1103 may be an optical amplifier, such as an erbium doped fiber amplifier (EDFA), a semiconductor optical amplifier (SOA), or other types of optical amplifiers.
  • EDFA erbium doped fiber amplifier
  • SOA semiconductor optical amplifier
  • the beam splitter 101 is used to perform beam splitting processing on the amplified laser signal (hereinafter referred to as signal light) to obtain the first signal light and the second signal light; output the first signal light to the unidirectional conduction device 601, and convert the second signal light to The second signal light is output to the second polarization conversion device 102 . That is to say, the amplified signal light is divided into two paths by the beam splitter 101 , one path enters the unidirectional conduction device 601 , and the other path enters the second polarization conversion device 102 as local oscillator light.
  • the second polarization conversion device 102 is configured to output the fourth signal light obtained after performing at least the above-mentioned third polarization processing on the above-mentioned second signal light to the mixer 40 .
  • the second polarization conversion device is optional, and details can be referred to the expression in FIG. 13 .
  • the unidirectional conduction device 601 is configured to output the first signal light from the beam splitter 101 to the optical antenna 6021 .
  • the optical antenna 6021 is configured to output at least collimated signal light on the first signal light to the first polarization conversion device 6022 .
  • the first polarization conversion device 6022 is configured to perform first polarization processing on the collimated first signal light; output the transmitted signal light after performing the first polarization processing on the collimated first signal light; receive the reflected signal light; output the third signal light after performing the second polarization processing on the reflected signal light to the optical antenna 6021. That is to say, the first polarization conversion device 6022 can be used to perform first polarization processing on the collimated first signal light, and perform second polarization processing on the reflected signal light.
  • Reflected signal light refers to the signal light that sends signal light to any object and returns.
  • the first signal light passes through the optical antenna 6021, and then passes through the first polarization conversion device 6022, and becomes circularly polarized light or elliptical polarized light (that is, the transmitted signal light), and hits any object to return the reflected signal light.
  • the reflected signal light returned by any object passes through the first polarization conversion device 6022 again, becomes the third signal light and enters the optical antenna 6021 .
  • the optical antenna 6021 is configured to output the third signal light to the unidirectional conducting device 601 . After receiving the third signal light, the optical antenna 6021 sends it back to the one-way conducting device 601 .
  • the unidirectional conduction device 601 is configured to output the third signal light to the mixer 40 . Since the polarization state of the first signal light has been transformed from polarization state 1 to polarization state 2, when the third signal light returns to the unidirectional conduction device 601, it will not go back the same way, but will be reflected into the mixer 40 .
  • Polarization state 1 refers to the polarization state of the first signal light, such as vertical polarization
  • polarization state 2 refers to the polarization state of the third signal light, such as horizontal polarization.
  • the mixer 40 is configured to mix the fourth signal light (local oscillator light) and the third signal light to obtain a mixed frequency signal.
  • the polarization state of the second signal light is the same as that of the third signal light.
  • Mixer 40 is a non-polarization mixing device. Regardless of the depolarization effect of the signal light reflected by any object, the polarization directions of the two paths of light entering the mixer 40 , that is, the third signal light and the fourth signal light are the same.
  • the same polarization state of the two signal lights means that the polarization directions of the two signal lights are the same
  • the orthogonal polarization states of the two signal lights means that the polarization directions of the two signal lights are orthogonal.
  • the detector 1104 is configured to detect the mixed frequency signal obtained after mixing by the mixer 40 .
  • the detector 1104 may be a PIN detector, an avalanche photodiode (avalanche photodiode, APD) detector, a single-photon avalanche diode (single-photon avalanche diode, SPAD) balanced detector or other detectors.
  • APD avalanche photodiode
  • SPAD single-photon avalanche diode
  • ADC1105 is used to sample the mixed frequency signal detected by the detector 1104 and send the sampled signal to the processing unit 1106 . That is to say, after the mixed frequency signal detected by the detector 1104 is sampled by the ADC 1105 , it is sent to the processing unit 1106 for subsequent signal processing.
  • the processing unit 1106 is configured to perform subsequent signal processing on the sampled signal to obtain information such as the position and speed of the detected object.
  • a coaxial transceiver detection system that is, a detection system using a coaxial optical system
  • various crosstalks will inevitably be introduced.
  • the actual detection system on the one hand, due to the reflected light from optical lenses, etc., it will be transmitted back to the mixer with a small loss to participate in the beat frequency, resulting in the appearance of short-distance spikes; on the other hand, due to the crosstalk of the device itself, part of the signal light will directly Leakage to the mixer for coherence interferes with close-range signal detection.
  • the detection system provided in the embodiment of the present application by using a polarization device (ie, a polarization module), the problem of crosstalk caused by reflected light and the characteristics of the device itself is effectively reduced.
  • the detection system provided by the embodiment of the present application is suitable for laser radar systems such as "line sending and line receiving", “surface sending and surface receiving”, and “point sending and point receiving”.
  • FIG. 12 is a schematic structural diagram of another detection system provided by an embodiment of the present application.
  • the detection system in FIG. 12 is a possible implementation of the detection system in FIG. 1 .
  • the detection system includes: a signal generator 1101, a laser 1102, an amplifier 1103, a beam splitter 101, a second polarization conversion device 102, a unidirectional conduction device 601, a first polarization conversion device 6023, an optical antenna 6024, Mixer 40 , detector 1104 , ADC 1105 , processing unit 1106 .
  • the beam splitter 101 and the second polarization conversion device 102 correspond to the beam splitting module 10 .
  • a possible structure of the beam splitting module 10 includes: a beam splitter 101 and a second polarization conversion device 102 .
  • the one-way conducting device 601 , the optical antenna 6021 and the first polarization conversion device 6022 correspond to the polarization module 20 .
  • a possible structure of the polarization module 20 includes: a unidirectional conduction device 601 , a first polarization conversion device 6023 and an optical antenna 6024 .
  • any one or more devices in Figure 12 can be reduced or replaced, and it can also be understood that in a specific implementation, the detection system can include all of the devices shown in Figure 12 One or more of the devices, the present application does not specifically limit the structural composition of the detection system.
  • An exemplary description of the functions of each device in Figure 12 is as follows:
  • the signal generator 1101 is used for modulating the laser 1102 .
  • the modulation method of the laser 1102 can be direct modulation or external modulation through a modulator, and the modulation method can be frequency modulated continuous wave, phase encoding or others.
  • the structure in which the signal generator 1101 modulates the laser 1102 can be replaced by: the laser signal output by the laser 1102 enters the modulator; the modulator modulates the input laser signal, and outputs the modulated laser signal to Amplifier 1103.
  • the modulator modulates the laser signal output by the laser 1102 according to the modulation signal input by the signal generator.
  • the laser 1102 is used to output the laser signal into the amplifier 1103 .
  • Laser 1102 may be a narrow linewidth laser, such as a semiconductor laser, fiber laser, or other type of laser.
  • the amplifier 1103 is used to amplify the input laser signal, and output the amplified laser signal to the beam splitter 101 .
  • Amplifier 1103 may be an optical amplifier, such as an erbium doped fiber amplifier (EDFA), a semiconductor optical amplifier (SOA), or other types of optical amplifiers.
  • EDFA erbium doped fiber amplifier
  • SOA semiconductor optical amplifier
  • the beam splitter 101 is used to perform beam splitting processing on the amplified laser signal (hereinafter referred to as signal light) to obtain the first signal light and the second signal light; output the first signal light to the unidirectional conduction device 601, and convert the second signal light to The second signal light is output to the second polarization conversion device 102 . That is to say, the amplified signal light is divided into two paths by the beam splitter 101 , one path enters the unidirectional conduction device 601 , and the other path enters the second polarization conversion device 102 as local oscillator light.
  • the second polarization conversion device 102 is configured to output the above-mentioned fourth signal light obtained after at least performing the above-mentioned third polarization processing on the above-mentioned second signal light to the above-mentioned mixer 40 .
  • the unidirectional conduction device 601 is configured to output the first signal light from the beam splitter 101 to the first polarization conversion device 6023 .
  • the first polarization conversion device 6023 is configured to output the fifth signal light after performing the first polarization processing on the first signal light to the optical antenna 6024 .
  • the optical antenna 6024 is configured to output the transmitted signal light after performing at least collimation processing on the fifth signal light; receive the reflected signal light, and output the reflected signal light to the first polarization conversion device 6023 .
  • the first polarization conversion device 6023 is configured to perform second polarization processing on the reflected signal light; and output the third signal light after performing the second polarization processing on the reflected signal light to the unidirectional conducting device 601 .
  • the unidirectional conduction device 601 is configured to output the third signal light to the mixer 40 . Since the polarization state of the first signal light has been transformed from polarization state 1 to polarization state 2, when the third signal light returns to the unidirectional conduction device 601, it will not go back the same way, but will be reflected into the mixer 40 .
  • Polarization state 1 refers to the polarization state of the first signal light, such as vertical polarization
  • polarization state 2 refers to the polarization state of the third signal light, such as horizontal polarization.
  • the mixer 40 is configured to mix the fourth signal light (local oscillator light) and the third signal light to obtain a mixed frequency signal.
  • the polarization state of the second signal light is the same as that of the third signal light.
  • Mixer 40 is a non-polarization mixing device. Regardless of the depolarization effect of the signal light emitted by any object, the polarization directions of the two paths of light entering the mixer 40 , that is, the third signal light and the fourth signal light are the same.
  • the detector 1104 is configured to detect the mixed frequency signal obtained after mixing by the mixer 40 .
  • the detector 1104 may be a PIN detector, an avalanche photodiode (avalanche photon diode, APD) detector, a balance detector or others.
  • APD avalanche photon diode
  • ADC1105 is used to sample the mixed frequency signal detected by the detector 1104 and send the sampled signal to the processing unit 1106 . That is to say, after the mixed frequency signal detected by the detector 1104 is sampled by the ADC 1105 , it is sent to the processing unit 1106 for subsequent signal processing.
  • the processing unit 1106 is configured to perform subsequent signal processing on the sampled signal to obtain information such as the position and speed of the detected object.
  • the optical antenna in FIG. 11 at least performs collimation processing on the first signal light output by the unidirectional conduction device 601, and sends the collimated signal light to The first polarization conversion device 6022; the first polarization conversion device 6023 in FIG. 12 performs the first polarization processing on the first signal light output by the unidirectional conduction device 601, and outputs the first polarization processing on the first signal light after performing the first polarization processing Five signal lights to the optical antenna 6024.
  • FIG. 13 is a schematic structural diagram of another detection system provided by an embodiment of the present application.
  • the detection system in FIG. 13 is a possible implementation of the detection system in FIG. 1 .
  • the detection system includes: a signal generator 1101, a laser 1102, an amplifier 1103, a beam splitting module 10, a unidirectional conduction device 601, an optical antenna 6021, a first polarization conversion device 6022, a mixer 40, and a detector 1104 , ADC1105 , and processing unit 1106 .
  • the beam splitting module 10 may be a beam splitter.
  • the one-way conducting device 601 , the optical antenna 6021 and the first polarization conversion device 6022 correspond to the polarization module 20 .
  • a possible structure of the polarization module 20 includes: a unidirectional conduction device 601 , an optical antenna 6021 and a first polarization conversion device 6022 .
  • 1301 represents the polarization direction of the signal light input by the beam splitting module 10
  • 1302 represents the polarization direction of the first signal light
  • 1303 represents the polarization direction of the second signal light
  • 1304 represents the polarization direction of the third signal light.
  • the signal generator 1101 is used for modulating the laser 1102 .
  • the modulation method of the laser 1102 can be direct modulation or external modulation through a modulator, and the modulation method can be frequency modulated continuous wave, phase encoding or others.
  • the structure in which the signal generator 1101 modulates the laser 1102 can be replaced by: the laser signal output by the laser 1102 enters the modulator; the modulator modulates the input laser signal, and outputs the modulated laser signal to Amplifier 1103.
  • the modulator modulates the laser signal output by the laser 1102 according to the modulation signal input by the signal generator.
  • the laser 1102 is used to output the laser signal into the amplifier 1103 .
  • Laser 1102 may be a narrow linewidth laser, such as a semiconductor laser, fiber laser, or other type of laser.
  • the amplifier 1103 is used to amplify the input laser signal, and output the amplified laser signal to the beam splitter 101 .
  • Amplifier 1103 may be an optical amplifier, such as EDFA, SOA or other types of optical amplifiers.
  • the beam splitting module 10 is used to perform beam splitting processing on the amplified laser signal (hereinafter referred to as signal light) to obtain the first signal light and the second signal light; output the first signal light to the unidirectional conduction device 601, and convert the second signal light to The two signal lights are output to the mixer 40 . That is to say, the amplified signal light is divided into two paths through the beam splitting module 10 , one path enters the unidirectional conduction device 601 , and the other path enters the mixer 40 as local oscillator light. In the embodiment of the present application, the polarization state of the first signal light is the same as that of the second signal light.
  • the unidirectional conduction device 601 is configured to output the first signal light from the beam splitting module 10 to the optical antenna 6021 .
  • the optical antenna 6021 is configured to output at least collimated signal light on the first signal light to the first polarization conversion device 6022 .
  • the first polarization conversion device 6022 is configured to perform first polarization processing on the collimated first signal light; output the transmitted signal light after performing the first polarization processing on the collimated first signal light; receive the reflected signal light; output the third signal light after performing the second polarization processing on the reflected signal light to the optical antenna 6021. That is to say, the first polarization conversion device 6022 can be used to perform first polarization processing on the collimated first signal light, and perform second polarization processing on the reflected signal light.
  • Reflected signal light refers to the signal light that sends signal light to any object and returns.
  • the first signal light passes through the optical antenna 6021, and then passes through the first polarization conversion device 6022, and becomes circularly polarized light or elliptical polarized light (that is, the transmitted signal light), and hits any object to return the reflected signal light.
  • the reflected signal light returned by any object passes through the first polarization conversion device 6022 again, becomes the third signal light and enters the optical antenna 6021 .
  • the optical antenna 6021 is configured to output the third signal light to the unidirectional conducting device 601 . That is to say, after receiving the third signal light, the optical antenna 6021 sends it back to the one-way conducting device 601 .
  • the unidirectional conduction device 601 is configured to output the third signal light to the mixer 40 . Since the polarization state of the first signal light has been transformed from polarization state 1 to polarization state 2, when the third signal light returns to the unidirectional conduction device 601, it will not go back the same way, but will be reflected into the mixer 40 .
  • Polarization state 1 refers to the polarization state of the first signal light, such as vertical polarization
  • polarization state 2 refers to the polarization state of the third signal light, such as horizontal polarization.
  • the mixer 40 is configured to mix the second signal light (local oscillator light) and the third signal light to obtain a mixed frequency signal.
  • the polarization state of the second signal light is orthogonal to the polarization state of the third signal light.
  • the mixer 40 is a polarization mixing device. Regardless of the depolarization effect of the signal light emitted by any object, the polarization directions of the two paths of light entering the mixer 40 , that is, the third signal light and the second signal light are orthogonal.
  • the detector 1104 is configured to detect the mixed frequency signal obtained after mixing by the mixer 40 .
  • the detector 1104 may be a PIN detector, an avalanche photodiode (avalanche photon diode, APD) detector, a balance detector or others.
  • APD avalanche photon diode
  • ADC1105 is used to sample the mixed frequency signal detected by the detector 1104 and send the sampled signal to the processing unit 1106 . That is to say, after the mixed frequency signal detected by the detector 1104 is sampled by the ADC 1105 , it is sent to the processing unit 1106 for subsequent signal processing.
  • the processing unit 1106 is configured to perform subsequent signal processing on the sampled signal to obtain information such as the position and speed of the detected object.
  • Comparing the detection system in FIG. 13 with the detection system in FIG. 11 shows that the structure of the beam splitting module 10 in FIG. 13 is different from that of the beam splitting module in FIG. 11 .
  • the structure of the polarization module 20 in FIG. 13 can be replaced with the structure of the polarization module 20 in FIG. 12 .
  • FIG. 14 is a schematic structural diagram of another detection system provided by an embodiment of the present application.
  • the detection system in FIG. 14 is a possible implementation of the detection system in FIG. 1 .
  • the detection system includes: a signal generator 1101, a laser 1102, an amplifier 1103, a beam splitting module 10, a unidirectional conduction device 601, an optical antenna 6021, a first polarization conversion device 6022, a mixer 40, and a detector 1104 , ADC1105 , and processing unit 1106 .
  • the beam splitting module 10 may be a polarizing beam splitter.
  • the one-way conducting device 601 , the optical antenna 6021 and the first polarization conversion device 6022 correspond to the polarization module 20 .
  • a possible structure of the polarization module 20 includes: a unidirectional conduction device 601 , an optical antenna 6021 and a first polarization conversion device 6022 .
  • 1401 represents the polarization direction of the signal light input by the beam splitting module 10
  • 1402 represents the polarization direction of the first signal light
  • 1403 represents the polarization direction of the second signal light
  • 1404 represents the polarization direction of the third signal light.
  • the signal generator 1101 is used for modulating the laser 1102 .
  • the modulation method of the laser 1102 can be direct modulation or external modulation through a modulator, and the modulation method can be frequency modulated continuous wave, phase encoding or others.
  • the structure in which the signal generator 1101 modulates the laser 1102 can be replaced by: the laser signal output by the laser 1102 enters the modulator; the modulator modulates the input laser signal, and outputs the modulated laser signal to Amplifier 1103.
  • the modulator modulates the laser signal output by the laser 1102 according to the modulation signal input by the signal generator.
  • the laser 1102 is used to output the laser signal into the amplifier 1103 .
  • Laser 1102 may be a narrow linewidth laser, such as a semiconductor laser, fiber laser, or other type of laser.
  • the amplifier 1103 is used to amplify the input laser signal, and output the amplified laser signal to the beam splitter 101 .
  • Amplifier 1103 may be an optical amplifier, such as an erbium doped fiber amplifier (EDFA), a semiconductor optical amplifier (SOA), or other types of optical amplifiers.
  • EDFA erbium doped fiber amplifier
  • SOA semiconductor optical amplifier
  • the beam splitting module 10 is configured to perform beam splitting processing on the input signal light to obtain the first signal light and the second signal light, output the first signal light to the unidirectional conduction device 601, and output the second signal light to the frequency mixing device 40.
  • the polarization state of the first signal light is orthogonal to the polarization state of the second signal light.
  • the unidirectional conduction device 601 is configured to output the first signal light from the beam splitting module 10 to the optical antenna 6021 .
  • the optical antenna 6021 is configured to output at least collimated signal light on the first signal light to the first polarization conversion device 6022 .
  • the first polarization conversion device 6022 is configured to perform first polarization processing on the collimated first signal light; output the transmitted signal light after performing the first polarization processing on the collimated first signal light; receive the reflected signal light; output the third signal light after performing the second polarization processing on the reflected signal light to the optical antenna 6021. That is to say, the first polarization conversion device 6022 can be used to perform first polarization processing on the collimated first signal light, and perform second polarization processing on the reflected signal light.
  • Reflected signal light refers to the signal light that sends signal light to any object and returns.
  • the first signal light passes through the optical antenna 6021, and then passes through the first polarization conversion device 6022, and becomes circularly polarized light or elliptical polarized light (that is, the transmitted signal light), and hits any object to return the reflected signal light.
  • the reflected signal light returned by any object passes through the first polarization conversion device 6022 again, becomes the third signal light and enters the optical antenna 6021 .
  • the optical antenna 6021 is configured to output the third signal light to the unidirectional conducting device 601 . After receiving the third signal light, the optical antenna 6021 sends it back to the one-way conducting device 601 .
  • the unidirectional conduction device 601 is configured to output the third signal light to the mixer 40 . Since the polarization state of the first signal light has been transformed from polarization state 1 to polarization state 2, when the third signal light returns to the unidirectional conduction device 601, it will not go back the same way, but will be reflected into the mixer 40 .
  • Polarization state 1 refers to the polarization state of the first signal light, such as vertical polarization
  • polarization state 2 refers to the polarization state of the third signal light, such as horizontal polarization.
  • the mixer 40 is configured to mix the second signal light (local oscillator light) and the third signal light to obtain a mixed frequency signal.
  • the polarization state of the second signal light is the same as that of the third signal light.
  • Mixer 40 is a non-polarization mixing device. Regardless of the depolarization effect of the signal light emitted by any object, the polarization directions of the two paths of light entering the mixer 40 , that is, the second signal light and the third signal light are the same.
  • the detector 1104 is configured to detect the mixed frequency signal obtained after mixing by the mixer 40 .
  • the detector 1104 may be a PIN detector, an avalanche photodiode (avalanche photon diode, APD) detector, a balance detector or others.
  • APD avalanche photon diode
  • ADC1105 is used to sample the mixed frequency signal detected by the detector 1104 and send the sampled signal to the processing unit 1106 . That is to say, after the mixed frequency signal detected by the detector 1104 is sampled by the ADC 1105 , it is sent to the processing unit 1106 for subsequent signal processing.
  • the processing unit 1106 is configured to perform subsequent signal processing on the sampled signal to obtain information such as the position and speed of the detected object.
  • the structure of the polarization module 20 in FIG. 14 can be replaced with the structure of the polarization module 20 in FIG. 12 .
  • the beam splitting module 10 in FIG. 14 can output the second signal light to the second polarization conversion device 102; the second polarization conversion device 102 outputs at least the third polarization processing on the second signal light The obtained fourth signal light is sent to the mixer 40 .
  • FIG. 15A and 15B are examples of test results of a coaxial transceiving detection system using a non-polarizing device (circulator) as a non-reciprocal device.
  • Fig. 15A shows the signal and noise level under multiple measurements of the coaxial transceiver detection system using a non-polarized device
  • Fig. 15B is the spectrum after fast Fourier transform (FFT).
  • FFT fast Fourier transform
  • 16A and 16B are examples of test results of a coaxial transceiving detection system using a polarizing device as a non-reciprocal device. Under the same parameters and conditions, we replaced the polarization device as a non-reciprocal device for the coaxial transceiver detection system (that is, the detection system provided by this application), and the test results are shown in Figure 15A and Figure 15B. It can be seen from FIG. 16A that after precise adjustment, the level of the crosstalk signal in the signal spectrum is reduced from -40dBm to -50dBm, and the drop is close to 10dB. Because the polarization device effectively reduces the crosstalk caused by reflected light, the level of crosstalk signals is significantly reduced, which brings certain benefits to short-distance signal detection and low- to mid-frequency noise reduction.
  • the amplitude of the time domain signal depends more on the magnitude of the crosstalk signal.
  • a reduction in the level of the crosstalk signal in the frequency domain means that the amplitude of the signal in the time domain is also reduced.
  • the ADC for back-end processing can reduce the quantization range, thereby reducing (least significant bit, LSB) at a fixed number of bits, thereby reducing quantization noise.
  • the detection system provided by this paper effectively reduces the crosstalk problem caused by reflected light and the characteristics of the device itself by using a polarizing device.
  • the present application provides a laser radar system, and the laser radar system includes any detection system provided in the present application.
  • the detection system provided by this application can be used in laser radar systems such as "line sending and line receiving", “surface sending and surface receiving", and “point sending and point receiving”.
  • Fig. 10 can be regarded as an example of a lidar system provided in this application.
  • the present application provides a terminal device, and the terminal device includes the detection system provided in the present application.
  • the terminal device is a smart car (or an automatic driving device), on which one or more detection systems provided by this application are deployed.
  • the application provides a detection device, including at least one laser, at least one detector and any detection system provided by the application.

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Abstract

一种探测系统和终端设备，探测系统包括：分束模块（10）、偏振模块（20）以及混频器（40）；分束模块（10），用于对输入的信号光执行分束处理得到第一信号光以及第二信号光；偏振模块（20），用于输出对第一信号光至少执行第一偏振处理后的发射信号光；以及，获取发射信号光的反射信号光，并输出对反射信号光至少执行第二偏振处理后的第三信号光；混频器（40），用于对第二信号光和第三信号光执行混频处理；或者，用于对通过对第二信号光至少执行第三偏振处理后得到的第四信号光和第三信号光执行混频处理；可以有效降低串扰的影响。另外，偏振模块（20）本身带来的串扰较少。

Description

探测系统和终端设备 技术领域
本申请涉及激光探测领域，尤其涉及一种探测系统和终端设备。
背景技术
激光雷达按照采用的探测方式的不同可分为直接探测激光雷达和相干激光雷达。直接探测激光雷达是指采用直接探测方式的激光雷达。相干探测激光雷达是指采用相干探测方式的激光雷达。直接探测激光雷达通过测量的反射和接收光脉冲的时间延时差乘以光速获得往返距离，从而得到距离信息。但是，直接探测激光雷达需要高灵敏度的探测器、高峰值功率的发射脉冲信号，受噪声影响较大。相比之下，相干激光雷达使用连续光作为探测信号，通过本振光与信号光的混频获得信号的频率、幅度、相位信息，具有探测效率高、抗环境光干扰、实时获得速度信息等优点。
对于相干探测系统(例如相干激光雷达)来说，因为其对微弱信号的探测优势，串扰对其影响比对直接探测激光雷达的影响更大。相干探测系统中，对串扰的控制水平直接影响其探测的能力和准确性。因此，需要研究如何降低相干探测中的串扰影响。
发明内容
本申请公开了探测系统和终端设备，能够有效降低探测系统中的串扰影响。
第一方面，本申请实施例提供一种探测系统，包括：分束模块、偏振模块以及混频器；所述分束模块，用于对输入的信号光执行分束处理得到第一信号光以及第二信号光；所述偏振模块，用于输出对所述第一信号光至少执行第一偏振处理后的发射信号光；以及，获取所述发射信号光的反射信号光，并输出对所述反射信号光至少执行第二偏振处理后的第三信号光；所述混频器，用于对所述第二信号光和所述第三信号光执行混频处理；或者，用于对通过对所述第二信号光至少执行第三偏振处理后得到的第四信号光和所述第三信号光执行混频处理。
本申请实施例中，偏振模块用于输出对第一信号光至少执行第一偏振处理后的发射信号光，以及输出对反射信号光至少执行第二偏振处理后的第三信号光。第三信号光可理解为对第一信号光至少执行第一偏振处理以及至少执行第二偏振处理后的信号光。只有第三信号光以及偏振态与第三信号光的偏振态相同的串扰光才能被输出至混频器。由于偏振态与第三信号光的偏振态不同的串扰光不能输出至混频器，因此可以有效降低串扰的影响。另外，偏振模块本身带来的串扰较少。
在一种可能的实现方式中，所述混频器为偏振混频器，所述第二信号光和所述第三信号光的偏振状态正交；或者，所述混频器为非偏振混频器，所述第四信号光和所述第三信号光的偏振状态相同。
在该实现方式中，偏振模块降低了反射光带来的串扰，即串扰光不会进入混频器，因此混频器对第二信号光和第三信号光执行混频处理或者对第三信号光和第四信号光执行混频处理均能提高混频效率，降低退偏振等非理想因素影响。
在一种可能的实现方式中，所述偏振模块包括：偏振变换模块和单向导通器件；所述单向导通器件，用于将所述第一信号光输出至所述偏振变换模块，以及，用于将所述第三信号光输出至所述混频器；所述偏振变换模块，用于对所述第一信号光执行所述第一偏振处理；以及，用于对所述反射信号光执行所述第二偏振处理。
在该实现方式中，单向导通器件用于将第一信号光输出至偏振变换模块，以及将第三信号光输出至混频器；能够避免将部分信号光泄露到混频器。
在一种可能的实现方式中，所述单向导通器件，还用于反射、过滤或者吸收从第一方向进入的第一偏振态的信号光，所述第一方向为所述第三信号光的输入方向，所述第一偏振态不同于所述第三信号光的偏振态。
在该实现方式中，单向导通器件，还用于反射、过滤或者吸收从第一方向进入的第一偏振态的信号光，这样大部分串扰光不会进入混频器；可以有效降低串扰的影响。
在一种可能的实现方式中，所述单向导通器件，用于将所述第三信号光从第一反射面反射至所述混频器；和/或所述单向导通器件，用于将从所述第一方向进入的第一偏振态的信号光从第二反射面反射出；所述第一反射面和所述第二反射面不同，所述第一偏振态不同于所述第三信号的偏振态。
在该实现方式中，单向导通器件，用于将第三信号光从第一反射面反射至混频器；和/或单向导通器件，用于将从第一方向进入的第一偏振态的信号光从第二反射面反射出；可以避免第一偏振态的信号光进入混频器，结构简单。
在一种可能的实现方式中，所述偏振变换模块包括：光学天线和第一偏振变换器件；所述光学天线，用于输出对所述第一信号光至少执行准直处理后的信号光至所述第一偏振变换器件，以及，用于输出所述第三信号光至所述单向导通器件；所述第一偏振变换器件，用于对准直处理后的所述第一信号光执行所述第一偏振处理；以及，用于输出对所述反射信号光执行所述第二偏振处理后的所述第三信号光；或者，所述第一偏振变换器件，用于输出对所述第一信号光执行所述第一偏振处理后的第五信号光至所述光学天线；以及，用于对所述反射信号光执行所述第二偏振处理；所述光学天线，用于输出对所述第五信号光至少执行准直处理后的所述发射信号光。
在该实现方式中，光学天线对信号光进行准直处理，可以使得信号光最大效率的耦合进入第一偏振变换器件或者使得信号光最大效率的耦合发射出。
在一种可能的实现方式中，所述分束模块包括：分束器和第二偏振变换器件；所述分束器，用于对输入的信号光执行分束处理得到所述第一信号光以及所述第二信号光；所述第二偏振变换器件，用于输出对所述第二信号光至少执行所述第三偏振处理后得到的所述第四信号光至所述混频器。示例性的，所述第四信号光的偏振态和所述第二信号光的偏振态正交。
在该实现方式中，第二偏振变换器件，用于输出对第二信号光至少执行第三偏振处理后得到的第四信号光至混频器，能够将所需偏振态的信号光输出至混频器。
在一种可能的实现方式中，所述第一信号光的偏振态和所述第二信号光的偏振态相同。
在一种可能的实现方式中，所述分束模块为偏振分束器；所述第一信号光的偏振态和所述第二信号光的偏振态正交，所述分束模块输入的信号光的偏振态与所述第一信号光的偏振态不正交且不平行。
在该实现方式中，分束模块对输入的信号光执行分束处理得到偏振态正交的第一信号光和第二信号光，能够保证混频器输入的本振光和信号光的偏振态相同，可提升混频效率，结构简单，不需要额外的偏振变换器件。
在一种可能的实现方式中，所述分束器为偏振分束器；所述分束器，具体用于对输入的信号光执行分束处理以及偏振态调节处理得到所述第一信号光以及所述第二信号光；所述第一信号光的偏振态和所述第二信号光的偏振态正交，所述分束器输入的信号光的偏振态与所述第一信号光的偏振态不正交且不平行。
在该实现方式中，分束模块对输入的信号光执行分束处理以及偏振态调节处理得到偏振态正交的第一信号光和第二信号光，能够保证混频器输入的本振光和信号光的偏振态正交，以便使用偏振混频器实现混频处理。
在一种可能的实现方式中，所述探测系统中的发射光路和接收光路同轴布置。
第二方面，本申请实施例提供一种激光雷达系统，包括上述第一方面或上述第一方面任意可能的实现方式所述的探测系统。
第三方面，本申请实施例提供一种终端设备，包括上述第一方面或上述第一方面任意可能的实现方式所述的探测系统。
第四方面，本申请实施例提供一种探测装置，包含至少一个激光器，至少一个探测器以及如上述第一方面或上述第一方面任意可能的实现方式所述的探测系统。
附图说明
图1为本申请实施例提供的一种探测系统的结构示意图；
图2A至图2C为本申请实施例提供的第一信号光的偏振态、第二信号光的偏振态、第三信号光的偏振态的示例；
图3A至图3D为本申请实施例提供的第一信号光的偏振态、第二信号光的偏振态、第三信号光的偏振态以及第四信号光的偏振态的示例；
图4A至图4C为本申请实施例提供的分束模块10输入的信号光的偏振态、第一信号光的偏振态、第二信号光的偏振态、第三信号光的偏振态的示例；
图5A至图5C为本申请实施例提供的分束模块10输入的信号光的偏振态、第一信号光的偏振态、第二信号光的偏振态、第三信号光的偏振态的示例；
图6为本申请实施例提供的一种偏振模块的结构示意图；
图7为本申请实施例提供的一种单向导通器件处理从第一方向进入的第三信号光和第一偏振态的信号光的示例；
图8A和图8B为本申请实施例提供的偏振变换模块602的结构示意图；
图9为本申请实施例提供的分束模块10的结构示意图；
图10为本申请实施例提供的一种发射光路和接收光路可同轴布置的示例；
图11为本申请实施例提供的另一种探测系统的结构示意图；
图12为本申请实施例提供的另一种探测系统的结构示意图；
图13为本申请实施例提供的另一种探测系统的结构示意图；
图14为本申请实施例提供的另一种探测系统的结构示意图；
图15A和图15B为使用非偏振器件(环形器)作为非互易器件的同轴收发探测系统的测试结果的示例；
图16A和图16B为使用偏振器件作为非互易器件的同轴收发探测系统的测试结果的示例。
具体实施方式
如背景技术部分所述，目前需要研究如何降低探测系统中的串扰影响。本申请提供了能够有效降低串扰影响的探测系统。另外，本申请提供的探测系统还能降低其包含的器件自身原因所致的串扰。
为更方便理解本申请提供的激光雷达，下面介绍一些激光雷达相关的知识。
同轴光学系统和旁轴光学系统
根据激光雷达中发射光路和接收光路布局的不同，可以包含两种基本的光学系统-同轴和旁轴光学系统。同轴光学系统中，发射光束所在轴线与接收光路所在轴线位于或部分位于同一光轴上，结构简单、收发效率高，但易受到近场后向散射光的影响。旁轴(也称双轴)光学系统中，激光束和接收器光轴分开，发射光束只可能在特定范围内与接收视场有重合。旁轴系统不易受到近场后向散射的影响，但存在近距离盲区。
在结构较为简单的同轴收发光学系统中，常常会引入各种串扰。这些串扰一部分是由于环形器等器件的自身原因所致，一部分是由于环境中的杂散光导致。其中，器件本身引入的串扰占有主要的比例。
在采用同轴光学系统的相干探测系统中，反射光经过器件会引入远大于目标反射光(即所需的信号光)的信号，与本振光混频后会极大地影响近距离信号的探测，并抬高远距离下噪声的水平。也就是说，采用同轴光学系统的相干探测系统中，串扰影响更为严重。
下面结合附图介绍本申请提供的探测系统的示例。
图1为本申请实施例提供的一种探测系统的结构示意图。如图1所示，探测系统包括：分束模块10、偏振模块20以及混频器40。在一些实施例中，分束模块10、偏振模块20以及混频器40的功能如下：
分束模块10，用于对输入的信号光执行分束处理得到第一信号光以及第二信号光；
偏振模块20，用于输出对上述第一信号光至少执行第一偏振处理后的发射信号光；以及，获取(或者说接收)上述发射信号光的反射信号光，并输出对上述反射信号光至少执行第二偏振处理后的第三信号光至混频器40；
混频器40，用于对上述第二信号光和上述第三信号光执行混频处理；或者，用于对通过对上述第二信号光至少执行第三偏振处理后得到的第四信号光和上述第三信号光执行混频处理。
在一些实施例中，分束模块10，还用于输出第一信号光至偏振模块20，以及输出第二信号光至混频器40；第三信号光的偏振态和第二信号光的偏振态正交，混频器40为偏振混频器。在一种可能的实现方式中，第二信号光的偏振态和第一信号光的偏振态相同，例如均为水平偏振或垂直偏振；第三信号光的偏振态和第一信号光的偏振态正交。
图2A至图2C为本申请实施例提供的第一信号光的偏振态、第二信号光的偏振态、第三信号光的偏振态的示例。图2A中，201表示第一信号光的偏振态，202表示第二信号光的偏振态，203表示第三信号光的偏振态；其中，第二信号光的偏振态和第一信号光的偏振态相同(均为水平偏振)，第三信号光的偏振态和第一信号光的偏振态正交，第三信号光的偏振态和第二信号光的偏振态正交。图2B中，204表示第一信号光的偏振态，205表示第二信号光的偏振态，206表示第三信号光的偏振态；其中，第二信号光的偏振态和第一信号光的偏振态相同(均为垂直偏振)，第三信号光的偏振态和第一信号光的偏振态正交，第三信号光的偏振态和第二信号光的偏振态正交。图2C中，207表示第一信号光的偏振态，208表示第二信号光的偏振态，209表示第三信号光的偏振态；其中，第二信号光的偏振态和第一信号光的 偏振态相同(均为垂直偏振)，第三信号光的偏振态和第一信号光的偏振态正交，第三信号光的偏振态和第二信号光的偏振态正交。
在一些实施例中，分束模块10，还用于输出第一信号光至偏振模块20，以及输出对第二信号光至少执行第三偏振处理后得到的第四信号光至混频器40；第四信号光的偏振态和第三信号光的偏振态相同，混频器40为非偏振混频器。在一种可能的实现方式中，第一信号光的偏振态和第二信号光的偏振态相同，例如均为水平偏振或垂直偏振；第三信号光的偏振态和第一信号光的偏振态正交，第三信号光的偏振态和第二信号光的偏振态正交，第二信号光的偏振态和第四信号光的偏振态正交。分束模块10对第二信号光至少执行第三偏振处理可以是对第二信号光进行偏振变换，例如将第二信号光由偏振态1变换为偏振态2，偏振态1和偏振态2正交。举例来说，分束模块10将第二信号光由水平偏振变换为垂直偏振，得到第四信号光。在一种可能的实现方式中，第一信号光的偏振态和第二信号光的偏振态相同或不同，第二信号光的偏振态和第四信号光的偏振态不正交且不平行，第三信号光的偏振态和第一信号光的偏振态不正交且不平行。在这些实施例中，只需保证第三信号光的偏振态和第四信号光的偏振态正交，可不对第一信号光的偏振态、第二信号光的偏振态或第三信号光的偏振态作限定。举例来说，第一信号光的偏振态和第二信号光的偏振态相同，第二信号光的偏振态和第四信号光的偏振态成45度，第三信号光的偏振态和第一信号光的偏振态成45度，第四信号光的偏振态和第三信号光的偏振态相同。又举例来说，第一信号光的偏振态和第二信号光的偏振态成90度，第二信号光的偏振态和第四信号光的偏振态成45度，第三信号光的偏振态和第一信号光的偏振态成45度，第四信号光的偏振态和第三信号光的偏振态相同。
图3A至图3D为本申请实施例提供的第一信号光的偏振态、第二信号光的偏振态、第三信号光的偏振态以及第四信号光的偏振态的示例。图3A中，301表示第一信号光的偏振态，302表示第二信号光的偏振态，303表示第三信号光的偏振态，304表示第四信号光的偏振态；其中，第一信号光的偏振态和第二信号光的偏振态相同(均为水平偏振)，第三信号光的偏振态和第一信号光的偏振态正交，第四信号光的偏振态和第二信号光的偏振态正交，第四信号光的偏振态和第三信号光的偏振态相同。图3B中，305表示第一信号光的偏振态，306表示第二信号光的偏振态，307表示第三信号光的偏振态，308表示第四信号光的偏振态；其中，第一信号光的偏振态和第二信号光的偏振态相同(均为垂直偏振)，第三信号光的偏振态和第一信号光的偏振态正交，第四信号光的偏振态和第二信号光的偏振态正交，第四信号光的偏振态和第三信号光的偏振态相同。图3C中，309表示第一信号光的偏振态，310表示第二信号光的偏振态，311表示第三信号光的偏振态，312表示第四信号光的偏振态；其中，第一信号光的偏振态和第二信号光的偏振态相同(垂直偏振)，第三信号光的偏振态和第一信号光的偏振态成45度(可以是其他角度)，第四信号光的偏振态和第二信号光的偏振态成45度(可以是其他角度)，第四信号光的偏振态和第三信号光的偏振态相同。图3D中，313表示第一信号光的偏振态，314表示第二信号光的偏振态，315表示第三信号光的偏振态，316表示第四信号光的偏振态；其中，第一信号光的偏振态和第二信号光的偏振态相同(非垂直偏振或水平偏振)，第三信号光的偏振态和第一信号光的偏振态正交，第四信号光的偏振态和第二信号光的偏振态正交，第四信号光的偏振态和第三信号光的偏振态相同。
在一些实施例中，分束模块10，还用于输出第一信号光至偏振模块20，以及输出第二信号光至混频器40；第一信号光的偏振态和第二信号光的偏振态正交，分束模块10输入的信号光的偏振态与第一信号光(或第二信号光)的偏振态不正交且不平行，第二信号光的偏振态和第三信号光的偏振态相同，混频器40为非偏振混频器。在一种可能的实现方式中，第三 信号光的偏振态和第一信号光的偏振态正交，例如均为水平偏振或垂直偏振。
图4A至图4C为本申请实施例提供的分束模块10输入的信号光的偏振态、第一信号光的偏振态、第二信号光的偏振态、第三信号光的偏振态的示例。图4A中，401表示分束模块10输入的信号光(即分束模块的输入信号光)的偏振态，402表示第一信号光的偏振态(垂直偏振)，403表示第二信号光的偏振态(水平偏振)，404表示第三信号光的偏振态；其中，第一信号光的偏振态和第二信号光的偏振态正交，第三信号光的偏振态和第一信号光的偏振态正交，第二信号光的偏振态和第三信号光的偏振态相同。图4B中，405表示分束模块10输入的信号光(即分束模块的输入信号光)的偏振态，406表示第一信号光的偏振态(水平偏振)，407表示第二信号光的偏振态(垂直偏振)，408表示第三信号光的偏振态；其中，第一信号光的偏振态和第二信号光的偏振态正交，第三信号光的偏振态和第一信号光的偏振态正交，第二信号光的偏振态和第三信号光的偏振态相同。图4C中，409表示分束模块10输入的信号光(即分束模块的输入信号光)的偏振态(例如水平偏振)，410表示第一信号光的偏振态(非垂直偏振或水平偏振)，411表示第二信号光的偏振态，412表示第三信号光的偏振态；其中，第一信号光的偏振态和第二信号光的偏振态正交，第三信号光的偏振态和第一信号光的偏振态正交，第二信号光的偏振态和第三信号光的偏振态相同。分束模块的输入信号光与第一信号光之间的偏振角度可以是45度，也可以是其他角度，本申请实施例不作限定。
在一些实施例中，分束模块10，还用于输出第一信号光至偏振模块20，以及输出对第二信号光至少执行第三偏振处理后得到的第四信号光至混频器40；第四信号光的偏振态和第三信号光的偏振态正交，混频器40为偏振混频器。在这些实施例中，第一信号光的偏振态和第二信号光的偏振态正交，分束模块10输入的信号光的偏振态与第一信号光(或第二信号光)的偏振态不正交且不平行，第二信号光的偏振态和第四信号光的偏振态正交，第三信号光的偏振态和第一信号光的偏振态正交。
图5A至图5C为本申请实施例提供的分束模块10输入的信号光的偏振态、第一信号光的偏振态、第二信号光的偏振态、第三信号光的偏振态以及第四信号光的偏振态的示例。图5A中，501表示分束模块10输入的信号光(即分束模块的输入信号光)的偏振态，502表示第一信号光的偏振态(垂直偏振)，503表示第二信号光的偏振态(水平偏振)，504表示第三信号光的偏振态，505表示第四信号光的偏振态；其中，第一信号光的偏振态和第二信号光的偏振态正交，第三信号光的偏振态和第一信号光的偏振态正交，第四信号光的偏振态和第二信号光的偏振态正交。图5B中，506表示分束模块10输入的信号光(即分束模块的输入信号光)的偏振态，507表示第一信号光的偏振态(水平偏振)，508表示第二信号光的偏振态(垂直偏振)，509表示第三信号光的偏振态，510表示第四信号光的偏振态；其中，第一信号光的偏振态和第二信号光的偏振态正交，第三信号光的偏振态和第一信号光的偏振态正交，第四信号光的偏振态和第二信号光的偏振态正交。图5C中，511表示分束模块10输入的信号光(即分束模块的输入信号光)的偏振态(例如水平偏振)，512表示第一信号光的偏振态(非垂直偏振或水平偏振)，513表示第二信号光的偏振态，514表示第三信号光的偏振态，515表示第四信号光的偏振态；其中，第一信号光的偏振态和第二信号光的偏振态正交，第三信号光的偏振态和第一信号光的偏振态正交，第四信号光的偏振态和第二信号光的偏振态正交。
在一些实施例中，第一信号光和第三信号光均为线偏振光，对第一信号光至少执行第一偏振处理后的发射信号光以及该发射信号光的反射信号光均为圆偏振光或椭圆偏振光。第四信号光可为线偏振光。在一些实施例中，偏振模块具备偏振光选择功能，即仅将特定偏振态 的信号光(例如第三信号光)输出至混频器，将其他偏振态的信号光均不输出至混频器的功能。
本申请提供的探测系统中，偏振模块用于输出对第一信号光至少执行第一偏振处理后的发射信号光；以及，获取(或者说接收)该发射信号光的反射信号光，并输出对该反射信号光至少执行第二偏振处理后的第三信号光至混频器40。由于偏振态与第三信号光的偏振态不同的串扰光不能输出至混频器，因此可以有效降低反射光串扰的影响。或者说，只有第三信号光和偏振态与该第三信号光的偏振态相同的串扰光才会被偏振模块输出至混频器(即偏振模块仅输出某种特定偏振态的信号光至混频器)，其他偏振态的串扰光均不能进入混频器，即大部分串扰光均不能进入混频器，因此可以有效降低串扰的影响。
下面结合附图介绍偏振模块20的一种可能的结构。
图6为本申请实施例提供的一种偏振模块的结构示意图。如图6所示，偏振模块20包括：单向导通器件601和偏振变换模块602。单向导通器件601和偏振变换模块602的功能如下：
单向导通器件601，用于将第一信号光输出至偏振变换模块，以及，用于将第三信号光输出至混频器40；
偏振变换模块602，用于对第一信号光执行第一偏振处理；以及，用于对反射信号光执行第二偏振处理。偏振变换模块602，还用于输出对第一信号光执行第一偏振处理后的发射信号光，以及输出对反射信号光执行第二偏振处理后的第三信号光至单向导通器件601。偏振变换模块602，还用于接收反射信号光。
单向导通器件601可以是单向导通的非互易器件。从第一方向进入单向导通器件601的信号光全部被发射、过滤或者吸收，即不能通过单向导通器件601；从第二方向进入单向导通器件601的信号光能够通过单向导通器件601。举例来说，单向导通器件601包括两个输入端，从一个输入端(对应于第一方向)输入的信号光全部被发射、过滤或者吸收，从另一个输入端(对应于第二方向)输入的信号光经过单向导通器件601并从其输出端输出。在一些实施例中，第一信号光从第二方向进入单向导通器件601，单向导通器件601将第一信号光输出至偏振变换模块602；第三信号光从第一方向进入单向导通器件601，单向导通器件601将第三信号光输入至混频器40。单向导通器件601，还用于反射、过滤或者吸收从第一方向进入的第一偏振态的信号光，上述第一方向为上述第三信号光的输入方向，上述第一偏振态不同于上述第三信号光的偏振态。也就是说，从第一方向进入单向导通器件601的第一偏振态的信号光被单向导通器件601反射、过滤或者吸收，即第一偏振态的信号光不会被输出至混频器。应理解，单向导通器件601具备偏振光选择功能，即将从第一方向进入的第二偏振态的信号光(例如第三信号光)输出至混频器，将从第一方向进入的第一偏振态的信号光反射、过滤或者吸收。第一偏振态是指任意不同于第二偏振态的偏振态。换句话说，单向导通器件601仅将从第一方向进入的第二偏振态的信号光(例如第三信号光)输出至混频器，从第一方向进入的其他偏振态(任意不同于第二偏振态的偏振态)的信号光不能输出至混频器。举例来说，单向导通器件601，用于将第三信号光从第一反射面反射至混频器；将从第一方向进入的第一偏振态的信号光从第二反射面反射出；上述第一反射面和上述第二反射面不同，上述第一偏振态不同于上述第三信号的偏振态。单向导通器件601可以为偏振分光器件或偏振光选择器件，例如为偏振分束器(polarization beam splitter，PBS)。图7为本申请实施例提供的一种单向导通器件处理从第一方向进入的第三信号光和第一偏振态的信号光的示例。如图7所示，从第一方向进入单向导通器件601的第三信号光从第一反射面(图中的上反射面)反射至混频器；从第一方向进入单向导通器件601的第一偏振态的信号光从第二反 射面反射出。
偏振变换模块602，用于输出对第一信号光至少执行第一偏振处理后的发射信号光，以及，接收发射信号光的反射信号光，并输出对反射信号光至少执行第二偏振处理后的第三信号光。可见，偏振变换模块602通过对第一信号光至少执行第一偏振处理，以及对反射信号光至少执行第二偏振处理，得到可被单向导通器件601输出至混频器的第三信号光。单向导通器件601具备偏振光选择功能，即将从第一方向进入的第三信号光输出至混频器，将从第二方向进入的第一偏振态的信号光反射、过滤或者吸收。这样只有第三信号光(所需的目标发射光)会被单向导通器件601输出至混频器，串扰光不会被输出至混频器，因此可以有效降低串扰的影响。
下面结合附图介绍偏振变换模块602可能的结构。
图8A和图8B为本申请实施例提供的偏振变换模块602的结构示意图。如图8A所示，偏振变换模块602包括：光学天线6021和第一偏振变换器件6022；其中，单向导通器件601输出的第一信号光进入光学天线。
在一些实施例中，光学天线6021和第一偏振变换器件6022的功能如下：
光学天线6021，用于输出对第一信号光至少执行准直处理后的信号光至第一偏振变换器件，以及，用于输出第三信号光至单向导通器件；
第一偏振变换器件6022，用于对准直处理后的上述第一信号光执行上述第一偏振处理；以及，用于输出对反射信号光执行第二偏振处理后的上述第三信号光。
第一偏振变换器件6022，还可用于接收反射信号光，以及将第三信号光输出至光学天线6021。第一偏振变换器件6022，还可用于输出对准直处理后的上述第一信号光执行第一偏振处理后的发射信号光。光学天线6021可包括准直器。例如光学天线6021包括1个或多个透镜组成的镜头。光学天线6021可对第一信号光进行准直，即对输入的光束进行准直。第一偏振变换器件6022可以为四分之一波片或其他。在一些实施例中，第一偏振变换器件6022具备如下特性：光束(任意线偏振光)单次(或者说一次)经过第一偏振变换器件6022可以从线偏振光(例如第一信号光)转换为圆偏振光或者椭圆偏振光，经过两次(出光、回光)第一偏振变换器件6022，则可以将光束从一个偏振态转换为与之正交的另一偏振态。第三信号光可视为第一信号光两次经过第一偏振变换器件6022得到的信号光，一次是第一偏振变换器件6022对准直处理后的上述第一信号光执行上述第一偏振处理输出发射信号光，一次是对反射信号光执行第二偏振输出第三信号光。发射信号光的偏振态和反射信号光的偏振态相同。
如图8B所示，偏振变换模块602包括：第一偏振变换器件6023和光学天线6024；其中，单向导通器件601输出的第一信号光进入第一偏振变换器件6023。
在一些实施例中，第一偏振变换器件6023和光学天线6024的功能如下：
第一偏振变换器件6023，用于输出对上述第一信号光执行上述第一偏振处理后的第五信号光至光学天线6024；以及，用于对反射信号光执行上述第二偏振处理；
光学天线6024，用于输出对上述第五信号光至少执行准直处理后的上述发射信号光。
光学天线6024，还可用于接收反射信号光，并将反射信号光输出至第一偏振变换器件6023。第一偏振变换器件6023，可用于输出对反射信号光执行上述第二偏振处理后的第三信号光至单向导通器件601。
光学天线6024可包括准直器。例如光学天线6024为1个或多个透镜组成的镜头。光学天线6024可对第五信号光进行准直，即对输入的光束进行准直。第一偏振变换器件6023可以为四分之一波片或其他。在一些实施例中，第一偏振变换器件6023具备如下特性：光束(任 意线偏振光)单次(或者说一次)经过第一偏振变换器件6023可以从线偏振光(例如第一信号光)转换为圆偏振光或者椭圆偏振光，经过两次(出光、回光)第一偏振变换器件6023，则可以将光束从一个偏振态转换为与之正交的另一偏振态。第三信号光可视为第一信号光两次经过第一偏振变换器件6023得到的信号光，一次是第一偏振变换器件6023对第一信号光执行上述第一偏振处理输出第五信号光，一次是对反射信号光执行第二偏振输出第三信号光。发射信号光的偏振态和反射信号光的偏振态相同。
偏振变换模块602中的光学天线的作用是使信号光最大效率的耦合进入所需的器件中。本申请实施例中，光学天线6024对信号光进行准直处理，可以使得信号光最大效率的耦合进入第一偏振变换器件6023或者使得信号光最大效率的耦合发射出探测系统。
下面结合附图介绍分束模块10可能的结构。
图9为本申请实施例提供的分束模块10的结构示意图。如图9所示，分束模块10包括：分束器101和第二偏振变换器件102。
分束器101，用于对输入的信号光执行分束处理得到第一信号光以及第二信号光；
第二偏振变换器件102，用于输出对上述第二信号光至少执行上述第三偏振处理后得到的上述第四信号光至上述混频器。
在一些实施例中，第一信号光的偏振态和第二信号光的偏振态相同，第四信号光的偏振态和第二信号光的偏振态正交。分束器101，具体用于对输入的信号光执行分束处理得到第一信号光以及第二信号光，将第一信号光输出至偏振模块20以及将第二信号光输出至第二偏振变换器件102。应理解，分束器101将其入射光按一定比例进行分光，一路作为信号光进入偏振模块20，另一路作为本振光进入第二偏振变换器件102。在实际应用中，可根据实际需要配置分束器101进行分光的比例，即作为信号光的比例和作为本振光的比例。第二偏振变换器件102的作用是对其输入的信号光(例如第二信号光)进行偏振转换。或者说，第二偏振变换器件102用于转换第二信号光(本振光)的偏振态，例如将第二信号光(即本振光)的偏振态转换90度。举例来说，第二偏振变换器件102将第二信号光从水平偏振转换为垂直偏振，得到第四信号光。第二偏振变换器件102可以是二分之一波片或其他。在这些实施例中，第二偏振变换器件102，用于输出对第二信号光至少执行上述第三偏振处理后得到的第四信号光至混频器，以便混频器对本振光(即第四信号光)和第三信号光做混频处理。
在一些实施例中，分束器101为偏振分束器，第一信号光的偏振态和第二信号光的偏振态正交，分束器101输入的信号光的偏振态与第一信号光的偏振态不正交且不平行。分束器101，可用于对输入的信号光执行分束处理以及偏振态调节处理(例如调节信号光的偏振态)得到第一信号光以及第二信号光，将第一信号光输出至偏振模块20以及将第二信号光输出至第二偏振变换器件102。假定光的传输方向为向纸面传播，可定义垂直偏振为偏振态1，水平偏振为偏振态2。入射到分束器101的光信号的偏振态为与偏振态1、偏振态2分别成一定角度(例如1°～89°)的偏振态3。利用偏振分束器的自身特性，分束器101可以基于偏振态3与偏振态1、偏振态2所呈现的具体角度调整信号路(对应于信号光)与本振路(对应于本振光)的分光比，实现分束器的功能。例如，分束器101通过调节偏振态3的具体角度(即偏振态调整处理)，使得大比例的光作为信号光，以偏振态1的状态(对应于第一信号光)进入偏振模块20；通过调节偏振态3的具体角度，使得小比例的光作为本振光，以偏振态2的状态(对应于第二信号光)进入第二偏振变换器件102。第二偏振变换器件102，用于输出对第二信号光至少执行上述第三偏振处理后得到的第四信号光至混频器。在这些实施例中，分束器101对输入的信号光执行分束处理以及偏振态调节处理得到偏振态正交的第一信号光和 第二信号光，第二偏振变换器件102输出对第二信号光至少执行上述第三偏振处理后得到的第四信号光至混频器，可以使得混频器输入的本振光和信号光的偏振态正交。应理解，在混频器40为偏振混频器时，分束模块10中的分束器101为偏振分束器，这样可使得混频器输入的本振光和信号光的偏振态正交。
在一些实施例中，分束模块10为分束器，第一信号光的偏振态和第二信号光的偏振态相同。分束模块10，具体用于对输入的信号光执行分束处理得到第一信号光以及第二信号光，将第一信号光输出至偏振模块20以及将第二信号光输出至混频器40。分束器101可将其入射光按一定比例进行分光，一路作为信号光进入偏振模块20，另一路作为本振光进入混频器。在实际应用中，可根据实际需要配置分束模块10进行分光的比例，即作为信号光和本振光的比例。在这些实施例中，分束模块10仅需对输入的信号光执行分束处理得到第一信号光以及第二信号光，结构简单、成本低。
在一些实施例中，分束模块10为偏振分束器，第一信号光的偏振态和第二信号光的偏振态正交，分束模块10输入的信号光的偏振态与第一信号光的偏振态不正交且不平行。假定光的传输方向为向纸面传播，可定义垂直偏振为偏振态1，水平偏振为偏振态2。入射到分束模块10的光信号的偏振态为与偏振态1、偏振态2分别成一定角度(例如1°～89°)的偏振态3。利用偏振分束器的自身特性，可以基于偏振态3与偏振态1、偏振态2所呈现的具体角度调整信号路(对应于信号光)与本振路(对应于本振光)的分光比，实现分束器的功能。例如，通过调节偏振态3的具体角度，使得大比例的光作为信号光，以偏振态1的状态进入偏振模块20；通过调节偏振态3的具体角度，使得小比例的光作为本振光，以偏振态2的状态进入混频器40。本申请实施例中，大比例可以是90％以上的分光比，小比例可以是10％以下的分光比。应理解，偏振态3的光信号入射至分束模块10，经分束模块10分光的大比例信号光为偏振态1，小比例本振光为偏振态2。本申请实施例中，分束模块10对输入的信号光执行分束处理得到偏振态正交的第一信号光和第二信号光，能够保证混频器输入的本振光和信号光的偏振态相同，可提升混频效率。
在一些实施例中，本申请提供的探测系统中的发射光路和接收光路可同轴布置。发射光路和接收光路同轴布置的情况称为同轴光学系统。同轴光学系统的优点是结构简单、收发效率高，但易受到串扰和杂散光的影响。这些实施例中的探测系统，结构简单、收发效率高，还不易受到串扰和杂散光的影响。图10为本申请实施例提供的一种发射光路和接收光路同轴布置的探测系统的示例。如图10所示，1001表示发射光源，1002表示准直光路，1003表示分光器件，1004表示扫描机构，1005表示目标物，1006表示聚焦透镜，1007表示探测器。如图10所示，发射光源发射的信号光依次经过准直光路1002(或者称为准直器)、分光器件1003、扫描机构1004达到目标物；经目标物反射的信号光依次经过扫描机构1004、分光器件1003，聚焦透镜1006到达探测器1007。本申请实施例中，发射光路是指从发射光(即发射光源发射的信号光)的产生开始至发射光通过分光器件1003发射出去的光路，接收光路是指从扫描机构1004接收到反射光至传输到探测器1007的光路。图10中，实线箭头表示发射光路，虚线箭头表示接收光路。从图10可以看出，发射光路和接收光路可同轴布置。图10中的探测系统可以为激光雷达系统，发射光源1001可以为激光器，探测器1007可以为PIN探测器、APD探测器、平衡探测器等。
前面介绍了分束模块10可能的结构以及偏振模块20可能的结构。下面结合附图描述图1中的探测系统一些可能的示例。
图11为本申请实施例提供的另一种探测系统的结构示意图。图11中的探测系统为图1 中的探测系统可能的实现方式。如图11所示，探测系统包括：信号发生器1101、激光器1102、放大器1103、分束器101、第二偏振变换器件102、单向导通器件601、光学天线6021、第一偏振变换器件6022、混频器40、探测器1104、模数转换器(analog to digital converter，ADC)1105、处理单元1106。应理解，分束器101和第二偏振变换器件102对应于分束模块10。或者说，分束模块10一种可能的结构包括：分束器101和第二偏振变换器件102。单向导通器件601、光学天线6021以及第一偏振变换器件6022对应于偏振模块20。或者说，偏振模块20一种可能的结构是包括：单向导通器件601、光学天线6021以及第一偏振变换器件6022。需要说明的是，在探测系统的具体设计和实现中，可以减少或者替换图11中的任一个或者多个器件，也可以理解为，具体的实现中，探测系统可以包括图11所呈现的所有器件中的一个或多个，本申请不具体限定探测系统的结构组成。图11中的各器件的功能示例性的说明如下：
信号发生器1101，用于对激光器1102进行调制。激光器1102的调制方法可以是直接调制或通过调制器进行外调制，调制方式可以是调频连续波、相位编码或其他。在一些实施例中，信号发生器1101对激光器1102进行调制的结构可替换为：激光器1102输出的激光信号进入调制器；调制器对输入的激光信号进行调制，并将调制后的激光信号输出至放大器1103。例如，调制器根据信号发生器输入的调制信号对激光器1102输出的激光信号进行调制。即在某些场景中，信号发生器是可选的。
激光器1102，用于输出激光信号进入放大器1103。激光器1102可以是窄线宽激光器，例如半导体激光器、光纤激光器或其他类型的激光器。
放大器1103，用于对输入的激光信号进行放大，并输出放大后的激光信号至分束器101。放大器1103可以为光放大器，例如掺铒光纤放大器(erbium doped fiber amplifier，EDFA)、半导体光放大器(semiconductor optical amplifier，SOA)或其他类型的光放大器。
分束器101，用于对放大后的激光信号(后续称信号光)执行分束处理得到第一信号光以及第二信号光；将第一信号光输出至单向导通器件601，以及将第二信号光输出至第二偏振变换器件102。也就是说，放大后的信号光经过分束器101分为两路，一路进入单向导通器件601，一路作为本振光进入第二偏振变换器件102。
第二偏振变换器件102，用于输出对上述第二信号光至少执行上述第三偏振处理后得到的第四信号光至混频器40。例如，在某些场景中，该第二偏振变换器件是可选的，具体可以参见图13的表述。
单向导通器件601，用于将来自分束器101的第一信号光输出至光学天线6021。
光学天线6021，用于输出对第一信号光至少执行准直处理后的信号光至第一偏振变换器件6022。
第一偏振变换器件6022，用于对准直处理后的第一信号光执行第一偏振处理；输出对准直处理后的第一信号光执行第一偏振处理后的发射信号光；接收反射信号光；输出对反射信号光执行第二偏振处理后的第三信号光至光学天线6021。也就是说，第一偏振变换器件6022可用于对准直处理后的第一信号光执行第一偏振处理，以及对反射信号光执行第二偏振处理。反射信号光是指发射信号光射到任意物体上返回的信号光。第一信号光经过光学天线6021，再经过第一偏振变换器件6022后，变为圆偏振光或椭圆偏振光(即发射信号光)，射到任意物体上返回反射信号光。由任意物体返回的反射信号光再一次经过第一偏振变换器件6022，变为第三信号光进入光学天线6021中。
光学天线6021，用于输出第三信号光至单向导通器件601。光学天线6021在接收到第三信号光后，将其送回单向导通器件601。
单向导通器件601，用于将第三信号光输出至混频器40。由于第一信号光的偏振态已经由偏振态1变换为偏振态2，第三信号光回到单向导通器件601的时候，并不会原路返回，而是被反射到混频器40中。偏振态1是指第一信号光的偏振态，例如垂直偏振；偏振态2是指第三信号光的偏振态，例如水平偏振。
混频器40，用于对第四信号光(本振光)和第三信号光进行混频，得到混频信号。第二信号光的偏振态和第三信号光的偏振态相同。混频器40为非偏振混频器件。不考虑任意物体反射的信号光的退偏振效应，进入混频器40的两路光，即第三信号光和第四信号光的偏振方向相同。本申请中，两个信号光的偏振态相同是指两个信号光的偏振方向相同，两个信号光的偏振态正交是指两个信号光的偏振方向正交。
探测器1104，用于对混频器40混频后得到的混频信号进行探测。探测器1104可以为PIN探测器、雪崩光电二极管(avalanche photon diode，APD)探测器、单光子雪崩二极管(single-photon avalanche diode，SPAD)平衡探测器或其他探测器。
ADC1105，用于对探测器1104探测到的混频信号进行采样，并将采样信号送入处理单元1106。也就是说，探测器1104探测到的混频信号经过ADC1105采样后，送入处理单元1106进行后续信号处理。
处理单元1106，用于对采样信号进行后续信号处理以得到探测对象的位置、速度等信息。
在同轴收发探测系统(即采用同轴光学系统的探测系统)中，会不可避免的引入各种串扰。在实际探测系统中，一方面由于光学镜片等反射光会以较小的损耗传输回混频器参与拍频，造成近距离尖峰的出现；另一方面由于器件本身的串扰，部分信号光会直接泄露到混频器进行相干，干扰近距离信号探测。
本申请实施例提供的探测系统中，通过使用偏振器件(即偏振模块)，有效降低了反射光、器件本身特性带来的串扰问题。本申请实施例提供的探测系统适用于“线发线收”、“面发面收”、“点发点收”等激光雷达系统中。
图12为本申请实施例提供的另一种探测系统的结构示意图。图12中的探测系统为图1中的探测系统可能的实现方式。如图12所示，探测系统包括：信号发生器1101、激光器1102、放大器1103、分束器101、第二偏振变换器件102、单向导通器件601、第一偏振变换器件6023、光学天线6024、混频器40、探测器1104、ADC1105、处理单元1106。应理解，分束器101和第二偏振变换器件102对应于分束模块10。或者说，分束模块10一种可能的结构包括：分束器101和第二偏振变换器件102。单向导通器件601、光学天线6021以及第一偏振变换器件6022对应于偏振模块20。或者说，偏振模块20一种可能的结构是包括：单向导通器件601、第一偏振变换器件6023和光学天线6024。需要说明的是，在探测系统的具体设计和实现中，可以减少或者替换图12中的任一个或者多个器件，也可以理解为，具体的实现中，探测系统可以包括图12所呈现的所有器件中的一个或多个，本申请不具体限定探测系统的结构组成。图12中的各器件的功能示例性的说明如下：
信号发生器1101，用于对激光器1102进行调制。激光器1102的调制方法可以是直接调制或通过调制器进行外调制，调制方式可以是调频连续波、相位编码或其他。在一些实施例中，信号发生器1101对激光器1102进行调制的结构可替换为：激光器1102输出的激光信号进入调制器；调制器对输入的激光信号进行调制，并将调制后的激光信号输出至放大器1103。例如，调制器根据信号发生器输入的调制信号对激光器1102输出的激光信号进行调制。
激光器1102，用于输出激光信号进入放大器1103。激光器1102可以是窄线宽激光器，例如半导体激光器、光纤激光器或其他类型激光器。
放大器1103，用于对输入的激光信号进行放大，并输出放大后的激光信号至分束器101。放大器1103可以为光放大器，例如掺铒光纤放大器(erbium doped fiber amplifier，EDFA)、半导体光放大器(semiconductor optical amplifier，SOA)或其他类型光放大器。
分束器101，用于对放大后的激光信号(后续称信号光)执行分束处理得到第一信号光以及第二信号光；将第一信号光输出至单向导通器件601，以及将第二信号光输出至第二偏振变换器件102。也就是说，放大后的信号光经过分束器101分为两路，一路进入单向导通器件601，一路作为本振光进入第二偏振变换器件102。
第二偏振变换器件102，用于输出对上述第二信号光至少执行上述第三偏振处理后得到的上述第四信号光至上述混频器40。
单向导通器件601，用于将来自分束器101的第一信号光输出至第一偏振变换器件6023。
第一偏振变换器件6023，用于输出对第一信号光执行第一偏振处理后的第五信号光至光学天线6024。
光学天线6024，用于输出对第五信号光至少执行准直处理后的发射信号光；接收反射信号光，并将反射信号光输出至第一偏振变换器件6023。
第一偏振变换器件6023，用于对反射信号光执行第二偏振处理；输出对反射信号光执行上述第二偏振处理后的第三信号光至单向导通器件601。
单向导通器件601，用于将第三信号光输出至混频器40。由于第一信号光的偏振态已经由偏振态1变换为偏振态2，第三信号光回到单向导通器件601的时候，并不会原路返回，而是被反射到混频器40中。偏振态1是指第一信号光的偏振态，例如垂直偏振；偏振态2是指第三信号光的偏振态，例如水平偏振。
混频器40，用于对第四信号光(本振光)和第三信号光进行混频，得到混频信号。第二信号光的偏振态和第三信号光的偏振态相同。混频器40为非偏振混频器件。不考虑任意物体发射的信号光的退偏振效应，进入混频器40的两路光，即第三信号光和第四信号光的偏振方向相同。
探测器1104，用于对混频器40混频后得到的混频信号进行探测。探测器1104可以为PIN探测器、雪崩光电二极管(avalanche photon diode，APD)探测器、平衡探测器或其他。
ADC1105，用于对探测器1104探测到的混频信号进行采样，并将采样信号送入处理单元1106。也就是说，探测器1104探测到的混频信号经过ADC1105采样后，送入处理单元1106进行后续信号处理。
处理单元1106，用于对采样信号进行后续信号处理以得到探测对象的位置、速度等信息。
对比图12中的探测系统与图11中的探测系统可知，图11中的光学天线对单向导通器件601输出的第一信号光至少执行准直处理，并将准直处理后的信号光至第一偏振变换器件6022；图12中的第一偏振变换器件6023对单向导通器件601输出的第一信号光执行第一偏振处理，并输出对第一信号光执行第一偏振处理后的第五信号光至光学天线6024。
图13为本申请实施例提供的另一种探测系统的结构示意图。图13中的探测系统为图1中的探测系统可能的实现方式。如图13所示，探测系统包括：信号发生器1101、激光器1102、放大器1103、分束模块10、单向导通器件601、光学天线6021、第一偏振变换器件6022、混频器40、探测器1104、ADC1105、处理单元1106。分束模块10可以是分束器。单向导通器件601、光学天线6021以及第一偏振变换器件6022对应于偏振模块20。或者说，偏振模块20一种可能的结构是包括：单向导通器件601、光学天线6021以及第一偏振变换器件6022。图13中，1301表示分束模块10输入的信号光的偏振方向，1302表示第一信号光的偏振方向， 1303表示第二信号光的偏振方向，1304表示第三信号光的偏振方向。图13中的各器件的功能如下：
信号发生器1101，用于对激光器1102进行调制。激光器1102的调制方法可以是直接调制或通过调制器进行外调制，调制方式可以是调频连续波、相位编码或其他。在一些实施例中，信号发生器1101对激光器1102进行调制的结构可替换为：激光器1102输出的激光信号进入调制器；调制器对输入的激光信号进行调制，并将调制后的激光信号输出至放大器1103。例如，调制器根据信号发生器输入的调制信号对激光器1102输出的激光信号进行调制。
激光器1102，用于输出激光信号进入放大器1103。激光器1102可以是窄线宽激光器，例如半导体激光器、光纤激光器或其他类型的激光器。
放大器1103，用于对输入的激光信号进行放大，并输出放大后的激光信号至分束器101。放大器1103可以为光放大器，例如EDFA、SOA或其他类型光放大器。
分束模块10，用于对放大后的激光信号(后续称信号光)执行分束处理得到第一信号光以及第二信号光；将第一信号光输出至单向导通器件601，以及将第二信号光输出至混频器40。也就是说，放大后的信号光经过分束模块10分为两路，一路进入单向导通器件601，一路作为本振光进入混频器40。在本申请实施例中，第一信号光的偏振态和第二信号光的偏振态相同。
单向导通器件601，用于将来自分束模块10的第一信号光输出至光学天线6021。
光学天线6021，用于输出对第一信号光至少执行准直处理后的信号光至第一偏振变换器件6022。
第一偏振变换器件6022，用于对准直处理后的第一信号光执行第一偏振处理；输出对准直处理后的第一信号光执行第一偏振处理后的发射信号光；接收反射信号光；输出对反射信号光执行第二偏振处理后的第三信号光至光学天线6021。也就是说，第一偏振变换器件6022可用于对准直处理后的第一信号光执行第一偏振处理，以及对反射信号光执行第二偏振处理。反射信号光是指发射信号光射到任意物体上返回的信号光。第一信号光经过光学天线6021，再经过第一偏振变换器件6022后，变为圆偏振光或椭圆偏振光(即发射信号光)，射到任意物体上返回反射信号光。由任意物体返回的反射信号光再一次经过第一偏振变换器件6022，变为第三信号光进入光学天线6021中。
光学天线6021，用于输出第三信号光至单向导通器件601。也就是说，光学天线6021在接收到第三信号光后，将其送回单向导通器件601。
单向导通器件601，用于将第三信号光输出至混频器40。由于第一信号光的偏振态已经由偏振态1变换为偏振态2，第三信号光回到单向导通器件601的时候，并不会原路返回，而是被反射到混频器40中。偏振态1是指第一信号光的偏振态，例如垂直偏振；偏振态2是指第三信号光的偏振态，例如水平偏振。
混频器40，用于对第二信号光(本振光)和第三信号光进行混频，得到混频信号。第二信号光的偏振态和第三信号光的偏振态正交。混频器40为偏振混频器件。不考虑任意物体发射的信号光的退偏振效应，进入混频器40的两路光，即第三信号光和第二信号光的偏振方向正交。
探测器1104，用于对混频器40混频后得到的混频信号进行探测。探测器1104可以为PIN探测器、雪崩光电二极管(avalanche photon diode，APD)探测器、平衡探测器或其他。
ADC1105，用于对探测器1104探测到的混频信号进行采样，并将采样信号送入处理单元1106。也就是说，探测器1104探测到的混频信号经过ADC1105采样后，送入处理单元1106 进行后续信号处理。
处理单元1106，用于对采样信号进行后续信号处理以得到探测对象的位置、速度等信息。
对比图13中的探测系统与图11中的探测系统可知，图13中的分束模块10的结构与图11中的分束模块的结构不同。
在一些实施例中，图13中的偏振模块20的结构可替换为图12中的偏振模块20的结构。
图14为本申请实施例提供的另一种探测系统的结构示意图。图14中的探测系统为图1中的探测系统可能的实现方式。如图14所示，探测系统包括：信号发生器1101、激光器1102、放大器1103、分束模块10、单向导通器件601、光学天线6021、第一偏振变换器件6022、混频器40、探测器1104、ADC1105、处理单元1106。分束模块10可以为偏振分束器。单向导通器件601、光学天线6021以及第一偏振变换器件6022对应于偏振模块20。或者说，偏振模块20一种可能的结构是包括：单向导通器件601、光学天线6021以及第一偏振变换器件6022。图14中，1401表示分束模块10输入的信号光的偏振方向，1402表示第一信号光的偏振方向，1403表示第二信号光的偏振方向，1404表示第三信号光的偏振方向。图14中的各器件的功能如下：
信号发生器1101，用于对激光器1102进行调制。激光器1102的调制方法可以是直接调制或通过调制器进行外调制，调制方式可以是调频连续波、相位编码或其他。在一些实施例中，信号发生器1101对激光器1102进行调制的结构可替换为：激光器1102输出的激光信号进入调制器；调制器对输入的激光信号进行调制，并将调制后的激光信号输出至放大器1103。例如，调制器根据信号发生器输入的调制信号对激光器1102输出的激光信号进行调制。
激光器1102，用于输出激光信号进入放大器1103。激光器1102可以是窄线宽激光器，例如半导体激光器、光纤激光器或其他类型激光器。
放大器1103，用于对输入的激光信号进行放大，并输出放大后的激光信号至分束器101。放大器1103可以为光放大器，例如掺铒光纤放大器(erbium doped fiber amplifier，EDFA)、半导体光放大器(semiconductor optical amplifier，SOA)或其他类型光放大器。
分束模块10，用于对输入的信号光执行分束处理得到第一信号光以及第二信号光，将第一信号光输出至单向导通器件601，以及将第二信号光输出至混频器40。在本申请实施例中，第一信号光的偏振态和第二信号光的偏振态正交。
单向导通器件601，用于将来自分束模块10的第一信号光输出至光学天线6021。
光学天线6021，用于输出对第一信号光至少执行准直处理后的信号光至第一偏振变换器件6022。
第一偏振变换器件6022，用于对准直处理后的第一信号光执行第一偏振处理；输出对准直处理后的第一信号光执行第一偏振处理后的发射信号光；接收反射信号光；输出对反射信号光执行第二偏振处理后的第三信号光至光学天线6021。也就是说，第一偏振变换器件6022可用于对准直处理后的第一信号光执行第一偏振处理，以及对反射信号光执行第二偏振处理。反射信号光是指发射信号光射到任意物体上返回的信号光。第一信号光经过光学天线6021，再经过第一偏振变换器件6022后，变为圆偏振光或椭圆偏振光(即发射信号光)，射到任意物体上返回反射信号光。由任意物体的返回的反射信号光再一次经过第一偏振变换器件6022，变为第三信号光进入光学天线6021中。
光学天线6021，用于输出第三信号光至单向导通器件601。光学天线6021在接收到第三信号光后，将其送回单向导通器件601。
单向导通器件601，用于将第三信号光输出至混频器40。由于第一信号光的偏振态已经 由偏振态1变换为偏振态2，第三信号光回到单向导通器件601的时候，并不会原路返回，而是被反射到混频器40中。偏振态1是指第一信号光的偏振态，例如垂直偏振；偏振态2是指第三信号光的偏振态，例如水平偏振。
混频器40，用于对第二信号光(本振光)和第三信号光进行混频，得到混频信号。第二信号光的偏振态和第三信号光的偏振态相同。混频器40为非偏振混频器件。不考虑任意物体发射的信号光的退偏振效应，进入混频器40的两路光，即第二信号光和第三信号光的偏振方向相同。
探测器1104，用于对混频器40混频后得到的混频信号进行探测。探测器1104可以为PIN探测器、雪崩光电二极管(avalanche photon diode，APD)探测器、平衡探测器或其他。
ADC1105，用于对探测器1104探测到的混频信号进行采样，并将采样信号送入处理单元1106。也就是说，探测器1104探测到的混频信号经过ADC1105采样后，送入处理单元1106进行后续信号处理。
处理单元1106，用于对采样信号进行后续信号处理以得到探测对象的位置、速度等信息。
在一些实施例中，图14中的偏振模块20的结构可替换为图12中的偏振模块20的结构。在一些实施例中，图14中的分束模块10可将第二信号光输出至第二偏振变换器件102；第二偏振变换器件102输出对上述第二信号光至少执行上述第三偏振处理后得到的上述第四信号光至上述混频器40。
图15A和图15B为使用非偏振器件(环形器)作为非互易器件的同轴收发探测系统的测试结果的示例。其中，图15A示出了使用非偏振器件的同轴收发探测系统多次测量下的信号、噪声水平，图15B为快速傅立叶变换(fast fourier transform，FFT)后的频谱。可以看到在低频(近距离)处，有一约-40dBm的串扰信号，远大于200～300MHz间的目标回波信号水平。这一串扰信号不仅使得近距离信号的探测变得非常困难，而且让低频到中频段的底噪水平都有所提高。图16A和图16B为使用偏振器件作为非互易器件的同轴收发探测系统的测试结果的示例。在相同参数与条件下，我们更换偏振器件作为非互易器件用于同轴收发探测系统(即采用本申请提供的探测系统)，测试结果如图15A和图15B所示。从图16A中可以看出，经过精确调整，信号频谱中串扰信号的水平由-40dBm降低到-50dBm，降幅接近10dB。由于偏振器件有效降低了反射光带来的串扰，因此串扰信号的水平显著降低，对近距离信号探测、低频到中频段噪声水平的降低都带来一定收益。
除此之外，由于串扰信号远大于信号水平，时域信号的幅度更多地取决于串扰信号的幅度。而频域串扰信号水平的降低，意味着时域信号的幅度也随之减小。这样，后端处理的ADC可以降低量化范围，从而在固定的位数下降低(least significant bit，LSB)，从而减小量化噪声。需要说明：上述结果只是在该测试条件下的效果示意图，其他条件下趋势类似但结果可能略有差别。
综上所述，本提供的探测系统通过使用偏振器件，有效降低了反射光、器件本身特性带来的串扰问题。
本申请提供了一种激光雷达系统，该激光雷达系统包括本申请提供的任意探测系统。本申请提供的探测系统可用于“线发线收”、“面发面收”、“点发点收”等激光雷达系统中。图10可视为本申请提供的一种激光雷达系统的示例。
本申请提供了一种终端设备，该终端设备包括本申请提供的探测系统。举例来说，终端设备为智能车(或者说自动驾驶装置)，该智能车上部署有一个或多个本申请提供的探测系统。
本申请提供一种探测装置，包含至少一个激光器，至少一个探测器以及本申请提供任一 种的探测系统。
以上所述，仅为本发明的具体实施方式，但本发明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发明揭露的技术范围内，可轻易想到变化或替换，都应涵盖在本发明的保护范围之内。因此，本发明的保护范围应以所述权利要求的保护范围为准。

Claims (12)

  1. 一种探测系统，其特征在于，包括：分束模块、偏振模块以及混频器；
    所述分束模块(10)，用于对输入的信号光执行分束处理得到第一信号光以及第二信号光；
    所述偏振模块(20)，用于输出对所述第一信号光至少执行第一偏振处理后的发射信号光；以及，获取所述发射信号光的反射信号光，并输出对所述反射信号光至少执行第二偏振处理后的第三信号光；
    所述混频器(40)，用于对所述第二信号光和所述第三信号光执行混频处理；或者，用于对通过对所述第二信号光至少执行第三偏振处理后得到的第四信号光和所述第三信号光执行混频处理。
  2. 根据权利要求1所述的探测系统，其特征在于，所述混频器(40)为偏振混频器，所述第二信号光和所述第三信号光的偏振状态正交；或者，所述混频器(40)为非偏振混频器，所述第四信号光和所述第三信号光的偏振状态相同。
  3. 根据权利要求1所述的探测系统，其特征在于，所述偏振模块包括：偏振变换模块(602)和单向导通器件(601)；
    所述单向导通器件(601)，用于将所述第一信号光输出至所述偏振变换模块，以及，用于将所述第三信号光输出至所述混频器(40)；
    所述偏振变换模块(602)，用于对所述第一信号光执行所述第一偏振处理；以及，用于对所述反射信号光执行所述第二偏振处理。
  4. 根据权利要求3所述的探测系统，其特征在于，
    所述单向导通器件(601)，还用于反射、过滤或者吸收从第一方向进入的第一偏振态的信号光，所述第一方向为所述第三信号光的输入方向，所述第一偏振态不同于所述第三信号光的偏振态。
  5. 根据权利要求3所述的探测系统，其特征在于，所述单向导通器件(601)包含至少一个反射面，其中：
    所述单向导通器件(601)，用于将所述第三信号光从第一反射面反射至所述混频器；和/或
    所述单向导通器件(601)，用于将从第一方向进入的第一偏振态的信号光从第二反射面反射出，所述第一方向为所述第三信号光的输入方向；所述第一反射面和所述第二反射面不同，所述第一偏振态不同于所述第三信号的偏振态。
  6. 根据权利要求3至5任一项所述的探测系统，其特征在于，所述偏振变换模块(602)包括：光学天线(6021,6024)和第一偏振变换器件(6022,6023)；
    所述光学天线(6021,6024)，用于输出对所述第一信号光至少执行准直处理后的信号光至所述第一偏振变换器件(6022,6023)，以及，用于输出所述第三信号光至所述单向导通器件(601)；
    所述第一偏振变换器件(6022,6023)，用于对准直处理后的所述第一信号光执行所述第一偏振处理；以及，用于输出对所述反射信号光执行所述第二偏振处理后的所述第三信号光；
    或者，
    所述第一偏振变换器件(6022,6023)，用于输出对所述第一信号光执行所述第一偏振处理后的第五信号光至所述光学天线(6021,6024)；以及，用于对所述反射信号光执行所述第二偏振处理；
    所述光学天线(6021,6024)，用于输出对所述第五信号光至少执行准直处理后的所述发射信号光。
  7. 根据权利要求1至6任一项所述的探测系统，其特征在于，所述分束模块(10)包括：分束器(101)和第二偏振变换器件(102)；
    所述分束器(101)，用于对输入的信号光执行分束处理得到所述第一信号光以及所述第二信号光；
    所述第二偏振变换器件(102)，用于输出对所述第二信号光至少执行所述第三偏振处理后得到的所述第四信号光至所述混频器(40)。
  8. 根据权利要求1至6任一项所述的探测系统，其特征在于，所述第一信号光的偏振态和所述第二信号光的偏振态相同。
  9. 根据权利要求1至6任一项所述的探测系统，其特征在于，所述分束模块(10)为偏振分束器；
    所述第一信号光的偏振态和所述第二信号光的偏振态正交，所述输入的信号光的偏振态与所述第一信号光的偏振态不正交且不平行。
  10. 根据权利要求1至9任一项所述的探测系统，其特征在于，所述探测系统包括发射光路和接收光路，以及，所述发射光路和接收光路同轴布置。
  11. 一种终端设备，其特征在于，包括权利要求1至10任一项所述的探测系统。
  12. 一种探测装置，包含至少一个激光器，至少一个探测器以及如权利要求1至9任一项所述的探测系统。
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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000338246A (ja) * 1999-05-28 2000-12-08 Mitsubishi Electric Corp コヒーレントレーザレーダ装置
CN102213763A (zh) * 2011-04-11 2011-10-12 哈尔滨工业大学 基于锁模激光器的相干多普勒测风激光雷达测距系统及测距方法
CN103116164A (zh) * 2013-01-25 2013-05-22 哈尔滨工业大学 外差脉冲压缩式多功能激光雷达及其控制方法
US20180224547A1 (en) * 2017-02-03 2018-08-09 Blackmore Sensors and Analytics Inc. Method and system for doppler detection and doppler correction of optical phase-encoded range detection
CN112305550A (zh) * 2019-08-01 2021-02-02 宁波飞芯电子科技有限公司 相干探测装置及方法
CN112639529A (zh) * 2020-07-30 2021-04-09 华为技术有限公司 一种激光雷达和智能车辆

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000338246A (ja) * 1999-05-28 2000-12-08 Mitsubishi Electric Corp コヒーレントレーザレーダ装置
CN102213763A (zh) * 2011-04-11 2011-10-12 哈尔滨工业大学 基于锁模激光器的相干多普勒测风激光雷达测距系统及测距方法
CN103116164A (zh) * 2013-01-25 2013-05-22 哈尔滨工业大学 外差脉冲压缩式多功能激光雷达及其控制方法
US20180224547A1 (en) * 2017-02-03 2018-08-09 Blackmore Sensors and Analytics Inc. Method and system for doppler detection and doppler correction of optical phase-encoded range detection
CN112305550A (zh) * 2019-08-01 2021-02-02 宁波飞芯电子科技有限公司 相干探测装置及方法
CN112639529A (zh) * 2020-07-30 2021-04-09 华为技术有限公司 一种激光雷达和智能车辆

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