lidar device

Abstract

The lidar device comprises: a light source (1) that outputs laser light; a wavelength divider / splitter (2) that receives the laser light output from the light source (1) and outputs local oscillation light and multiple signal lights; multiple amplifiers (5a-5c) that correspond to the multiple signal lights output from the wavelength divider / splitter (2) respectively, and amplify the corresponding signal lights; and multiple optical transceivers (7a-7c) that correspond to the multiple amplifiers (5a-5c) respectively, radiating the signal lights output from the corresponding amplifiers (5a-5c) into space as transmitted light, and receiving the scattered light from the target in space as received light. The light source includes a signal processing device (8) that calculates the distance to the target and the properties of the target based on the received light from multiple optical transceivers (7a-7c) and the local oscillation light from the wavelength division / splitter (2); and multiple transceiver separation devices (6a-6c) that correspond to multiple amplifiers (5a-5c) and multiple optical transceivers (7a-7c) respectively, which couple the transmitted light from multiple amplifiers (5a-5c) to the corresponding optical transceivers (7a-7c) and couple the received light received by multiple optical transceivers (7a-7c) to the corresponding signal processing device (8).

Description

Technical Field

[0001] This disclosure relates to a lidar device that radiates signal light into space, receives scattered light from a target existing in space, and calculates the distance to the target and the speed of the target. Background Technology

[0002] Such a lidar device is shown in Patent Document 1.

[0003] Patent document 1 discloses a monostatic lidar device that switches the direction of laser illumination by an optical switch, radiates laser in multiple directions, receives scattered light from the target and calculates the distance to the target and the speed of the target.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: International Publication No. 2017-130315 Summary of the Invention

[0007] The problem the invention aims to solve

[0008] In the monostatic lidar device shown in Patent Document 1, the laser irradiation direction is changed by switching a switch. Therefore, compared with a structure that mechanically controls the laser irradiation direction, it is easier to reduce the size of the device, lower the price, and increase reliability.

[0009] On the other hand, the light scattered backward by the transmitted light through the optical switch may be mixed into the received light, which is expected to further improve the signal-to-noise ratio (SN ratio) of the received signal.

[0010] This disclosure was made in view of the above aspects, and its object is to obtain a lidar device that improves the signal-to-noise ratio (SN ratio) based on the received signal from the scattered light from the target in a lidar device that radiates laser light in multiple directions, receives scattered light from the target, and calculates the distance to the target and the velocity of the target.

[0011] means for solving problems

[0012] The lidar device disclosed herein comprises: a light source that outputs laser light; a wavelength divider / splitter that receives the laser light output from the light source and outputs local oscillation light and multiple signal lights; multiple amplifiers that correspond to the multiple signal lights output from the wavelength divider / splitter, respectively, and amplify the corresponding signal lights; multiple optical transceivers that are configured to radiate in directions different from each other, each corresponding to the multiple amplifiers, radiating the signal lights output from the corresponding amplifiers as transmitted light into space, and receiving scattered light from a target existing in space based on the radiated transmitted light as received light; a signal processing unit that calculates the distance to the target and the properties of the target based on the received light from the multiple optical transceivers and the local oscillation light from the wavelength divider / splitter; and multiple transceiver separation units that correspond to the multiple amplifiers and the multiple optical transceivers, respectively, coupling the transmitted light from the multiple amplifiers to the corresponding optical transceivers, and coupling the received light received by the multiple optical transceivers to the corresponding signal processing unit.

[0013] The effects of the invention

[0014] According to this disclosure, the transmitted light is separated by a wavelength division multiplexing (WDM) / splitter before the transceiver separation device. Therefore, unwanted scattered light from the WDM / splitter can be prevented from mixing into the received light, thereby improving the signal-to-noise ratio (SN ratio) of the received signal based on the received light. Attached Figure Description

[0015] Figure 1 This is a structural diagram showing the lidar device according to Embodiment 1.

[0016] Figure 2 This is a structural diagram showing the lidar device according to Embodiment 2.

[0017] Figure 3 This is a structural diagram showing the lidar device of Embodiment 3.

[0018] Figure 4 This is a structural diagram showing the lidar device of Embodiment 4.

[0019] Figure 5 This is a structural diagram showing the transceiver separation device in the lidar device of Embodiment 4.

[0020] Figure 6 This is a structural diagram showing the lidar device of Embodiment 5.

[0021] Figure 7 This is a structural diagram showing the lidar device according to Embodiment 6. Detailed Implementation

[0022] Implementation method 1.

[0023] based on Figure 1 The following describes the LiDAR (Light Detection and Ranging, Laser Imaging Detection and Ranging) device according to Embodiment 1.

[0024] The lidar device in Embodiment 1 is based on a monostatic lidar device that radiates laser light in multiple directions, receives scattered light from a target, and calculates the distance to the target and the properties of the target. Specifically, it is based on a lidar device with multiple optical transceivers that radiate laser-based signal light into space and receive scattered light from a target existing in space as received light.

[0025] Regarding the nature of the target being measured, when the target is a Doppler lidar device for wind measurement, it is the wind speed of the target; when the target is a lidar device used for measuring distance and imaging in three-dimensional high-speed photography, it is the contrast of the image of the photographed object; and when the target is a lidar device used for measuring the concentration distribution of the gas in the target, it is the concentration of the gas in the target.

[0026] The lidar device includes a light source 1, a beam splitter / splitter 2 with a beam splitter 3 and a splitter 4, multiple amplifiers 5, multiple transceiver separation devices 6, multiple optical transceiver devices 7, and a signal processing device 8.

[0027] In Embodiment 1, it is shown that the plurality of amplifiers 5, the plurality of transceiver separation devices 6, and the plurality of optical transceiver devices 7 each have the first to the third type. For the first to the third type, a to c are appended after the reference numerals to distinguish them, but in the case of a brief description, such as when explaining common matters, the appended a to c are omitted and the description is carried out.

[0028] Furthermore, in Embodiment 1, the number of amplifier 5, transceiver separation device 6 and optical transceiver device 7 is set to 3, but it can also be 2, or more than 4.

[0029] In summary, the system is equipped with the same number of amplifiers 5 and transceiver separation devices 6 as the number of optical transceiver devices 7 configured to radiate laser light in multiple directions and receive scattered light from the target being measured.

[0030] That is, the optical transceiver 7, the amplifier 5, and the transceiver separation device 6 are respectively provided.

[0031] Specifically, the first optical transceiver 7a, the first amplifier 5a, and the first transceiver splitter 6a correspond to each other; the second optical transceiver 7b, the second amplifier 5b, and the second transceiver splitter 6b correspond to each other; and the third optical transceiver 7c, the third amplifier 5c, and the third transceiver splitter 6c correspond to each other.

[0032] The light source 1, the demultiplexer 3, the distributor 4, the multiple amplifiers 5, the multiple transceiver separation devices 6, and the signal processing device 8 are connected to each other via optical transmission units that serve as optical fiber cables 9-12 and 14, respectively.

[0033] In addition, the optical transmission units of optical fiber cables 9-12 and 14 are not limited to optical fiber cables. They can also be optically coupled between light source 1, demultiplexer 3, distributor 4, multiple amplifiers 5, multiple transceiver separation devices 6, and signal processing device 8 through free space propagation.

[0034] Multiple transceiver separation devices 6 and multiple optical transceiver devices 7 are connected by optical coupling through free space propagation, and are represented as optical transmission unit 13 in the figure.

[0035] Light source 1 outputs laser light. Light source 1 can output laser light of a single wavelength, or it can output laser light of multiple different wavelengths.

[0036] In the case where light source 1 is a light source that outputs multiple lasers of different wavelengths, it is any light source that outputs lasers by changing the wavelength over time or that simultaneously outputs multiple lasers of different wavelengths.

[0037] In addition to the fiber laser mentioned above, the light source 1 can also be constructed using a semiconductor laser, a solid-state laser, or a combination thereof.

[0038] Wavelength divider 3 splits the laser output from light source 1 and transmitted via fiber optic cable 9 into signal light and local oscillation light.

[0039] The ratio of the signal light to the local oscillation light is a fixed intensity ratio predetermined by the distributor 4 and the signal processing device 8, for example, 9:1.

[0040] The beam splitter 3 is a beam splitter composed of an optical fiber coupler, a half-reflector, and a lens.

[0041] The splitter 4 distributes the signal light from the demultiplexer 3 into multiple signal lights and outputs them. That is, the splitter 4 distributes the signal light split from the demultiplexer 3 and transmitted via fiber optic cable 10a into signal lights 1 through 3 and outputs them. The first signal light is input to the first amplifier 5a via fiber optic cable 11a, the second signal light is input to the second amplifier 5b via fiber optic cable 11b, and the third signal light is input to the third amplifier 5c via fiber optic cable 11c.

[0042] When the light source 1 outputs a single wavelength of laser light, the distributor 4 uses a time-dependent distribution unit such as an optical switch.

[0043] In addition, the splitter 4 can also be the same as the beam splitter 3, which is a beam splitter that divides and outputs the first signal light to the third signal light according to a fixed intensity ratio, and is composed of fiber optic couplers, half-reflectors and lenses.

[0044] In addition, the distributor 4 can also be a beam splitter that uses polarized light to divide and output the first to third signal lights.

[0045] When light source 1 is a light source that outputs multiple lasers of different wavelengths, distributor 4 uses a unit that separates the lasers according to the wavelength.

[0046] That is, distributor 4 selects and distributes the light input from light source 1, so that the light input from light source 1 is input to amplifiers 5a to 5c that can amplify the wavelength according to each wavelength.

[0047] The splitter 4 consists of an optical power splitter, an optical switch, a wavelength demultiplexer, or a combination thereof.

[0048] Alternatively, distributor 4 can be the same distributor as the distributor of light source 1 that outputs a laser of a single wavelength.

[0049] Wavelength divider 3 and splitter 4 constitute a wavelength divider / splitter 2 that receives the laser light output from light source 1 and outputs local oscillation light and multiple signal lights.

[0050] Amplifier 5 amplifies the intensity of the signal light distributed by distributor 4. That is, the first signal light distributed by distributor 4 and transmitted via fiber optic cable 11a is amplified by first amplifier 5a. The second signal light distributed by distributor 4 and transmitted via fiber optic cable 11b is amplified by second amplifier 5b. The third signal light distributed by distributor 4 and transmitted via fiber optic cable 11c is amplified by third amplifier 5c.

[0051] Amplifier 5 uses solid-state laser amplifiers such as fiber optic amplifiers, waveguide amplifiers, and slab amplifiers, or semiconductor optical amplifiers.

[0052] This lidar device uses multiple amplifiers, from the first amplifier 5a to the third amplifier 5c. Therefore, different types of amplifiers can be combined and used for the first amplifier 5a to the third amplifier 5c.

[0053] In the case where LMA fiber is used as fiber optic cable 12, amplifier 5 is an LMA fiber amplifier.

[0054] When LMA fiber is used as the fiber optic cable 12, it offers advantages such as enabling high-intensity light propagation. In particular, when an LMA fiber amplifier is used in amplifier 5, the number of components can be reduced.

[0055] In addition, if an LMA amplifier is used as amplifier 5, it is not necessary to use LMA fiber as fiber optic cable 12.

[0056] Furthermore, when a solid-state laser amplifier such as a slab amplifier is used as amplifier 5, LMA fiber may not be necessary for fiber optic cable 12 when the intensity of the light transmitted by fiber optic cable 12 is high. However, it is preferable to use LMA fiber for fiber optic cable 12 when suppressing transmission loss during high-intensity amplification.

[0057] When the optical transceiver 7 radiates and transmits light, the transceiver separation device 6 optically couples the amplifier 5 with the optical transceiver 7, and optically couples the optical transceiver 7 with the signal processing device 8 when the optical transceiver 7 receives and transmits light.

[0058] That is, the transceiver separation device 6 switches the output destination according to the light input source. Specifically, when the light input source is the amplifier 5, the output destination of the light is switched to the optical transceiver device 7, and when the light input source is the optical transceiver device 7, the output destination of the light is switched to the signal processing device 8.

[0059] The transceiver separation device 6 is an optical circulator consisting of an isolator and a polarization beam splitter using Faraday elements, or an optical circulator consisting of a polarization beam splitter and a quarter-wave plate, or a combination thereof.

[0060] When the first optical transceiver 7a radiates light, the first transceiver separation device 6a outputs the first signal light from the first amplifier 5a and transmitted via the optical fiber cable 12a to the optical transmission unit (free space propagation) 13a. The first signal light is input to the first optical transceiver 7a. When the first optical transceiver 7a receives scattered light, the first received light from the first optical transceiver 7a and transmitted via the optical transmission unit (free space propagation) 13a is output to the optical fiber cable 14a. The first received light is input to the signal processing device 8.

[0061] When the second optical transceiver 7b radiates light, the second transceiver separation device 6b outputs the second signal light from the second amplifier 5b and transmitted via the optical fiber cable 12b to the optical transmission unit (free space propagation) 13b. The second signal light is input to the second optical transceiver 7b. When the second optical transceiver 7b receives scattered light, the second received light from the second optical transceiver 7b and transmitted via the optical transmission unit (free space propagation) 13b is output to the optical fiber cable 14b. The second received light is input to the signal processing device 8.

[0062] When the third optical transceiver 7c radiates and transmits light, the third transceiver separation device 6c outputs the third signal light from the third amplifier 5c and transmitted via the optical fiber cable 12c to the optical transmission unit (free space propagation) 13c. The third signal light is input to the optical transceiver 7c. When the third optical transceiver 7c receives scattered light, the third received light from the third optical transceiver 7c and transmitted via the optical transmission unit (free space propagation) 13c is output to the optical fiber cable 14c. The third received light is input to the signal processing device 8.

[0063] The optical transceiver 7 radiates the signal light output from the amplifier 5 into space as the transmitting light, and receives the scattered light from the measurement target existing in space as the receiving light.

[0064] The optical transceiver 7 is a device such as an optical telescope, which has an optical antenna consisting of multiple refracting lenses or multiple reflecting mirrors.

[0065] The first optical transceiver 7a is connected to the first transceiver splitter 6a via the optical transmission unit (free space propagation) 13a, the second optical transceiver 7b is connected to the second transceiver splitter 6b via the optical transmission unit (free space propagation) 13b, and the third optical transceiver 7c is connected to the third transceiver splitter 6c via the optical transmission unit (free space propagation) 13c.

[0066] The first optical transceiver 7a to the third optical transceiver 7c are respectively configured to radiate in different directions from each other.

[0067] The signal processing device 8 analyzes the received light from the optical transceiver 7 and the local oscillation light from the demultiplexer 3 to calculate the distance to the target existing in space and the properties of the target.

[0068] That is, the signal processing device 8 performs analysis based on the first received light and the local oscillation light input from the demultiplexer 3 via the fiber optic cable 10b, and calculates the distance to the target and the properties of the target. The first received light is received by the first optical transceiver 7a based on the scattered light from the target, and is input to the signal processing device 8 via the optical transmission unit (free space propagation) 13a, the first transceiver separation device 6a and the fiber optic cable 14a.

[0069] Similarly, the signal processing device 8 performs analysis based on the second received light and the local oscillation light input from the demultiplexer 3 via the fiber optic cable 10b, and calculates the distance to the target and the properties of the target. The second received light is received by the second optical transceiver 7b based on the scattered light from the target and input to the signal processing device 8 via the optical transmission unit (free space propagation) 13b, the second transceiver separation device 6b and the fiber optic cable 14b.

[0070] Furthermore, the signal processing device 8 performs analysis based on the third received light and the local oscillation light input from the demultiplexer 3 via the fiber optic cable 10b, and calculates the distance to the target and the properties of the target. The third received light is received by the third optical transceiver 7c based on the scattered light from the target and input to the signal processing device 8 via the optical transmission unit (free space propagation) 13c, the third transceiver separation device 6c and the fiber optic cable 14c.

[0071] In the case of a Doppler lidar device for measuring wind speed, the signal processing unit 8 is configured to include a heterodyne receiver, an A / D converter, a high-speed Fourier transform device, a frequency shift analysis device, and a speed calculation device.

[0072] The heterodyne receiver causes the local oscillation light from the demultiplexer 3 to interfere with the received light from the transceiver separation device 6, and uses a balanced detector to detect the signal, that is, performs heterodyne detection.

[0073] An A / D converter performs digital conversion on analog electrical signals converted by a heterodyne receiver.

[0074] The high-speed Fourier transform device performs a high-speed Fourier transform (FFT) on the digital electrical signal from the A / D converter.

[0075] The frequency shift analysis device calculates the peak frequency based on the signal spectrum that has undergone Fourier transform by a high-speed Fourier transform device, thereby obtaining the Doppler frequency shift of the scattered light.

[0076] The velocity calculation device calculates the velocity of the target based on the Doppler frequency shift obtained by the frequency shift analysis device.

[0077] The high-speed Fourier transform device, frequency shift analysis device, and speed calculation device consist of a CPU (Central Processing Unit) and memory. The CPU executes the program stored in memory to calculate and measure the speed of the target.

[0078] The above describes the case where the signal processing device 8 performs processing using heterodyne detection, but it can also perform processing using detection methods other than heterodyne detection, such as video detection.

[0079] Next, the actions will be explained.

[0080] The action of sending light into the space where the target is located is explained.

[0081] There is no difference in operation whether light source 1 outputs a single wavelength of laser light or outputs multiple laser light sources with different wavelengths.

[0082] The laser light output from the light source 1 at unit time intervals is divided by the wavelength divider 3, and the divided signal light is transmitted to the distributor 4 via the fiber optic cable 10a.

[0083] The distributor 4 sequentially transmits the first signal light to the first amplifier 5a via fiber optic cable 11a, the second signal light to the second amplifier 5b via fiber optic cable 11b, and the third signal light to the third amplifier 5c via fiber optic cable 11c.

[0084] Amplifier 5, which receives the signal light distributed from distributor 4, amplifies the signal light, and the amplified signal light is transmitted to transceiver 6 via fiber optic cable 12.

[0085] The transceiver separation device 6 outputs the signal light amplified by the amplifier 5 and propagating in the optical fiber cable 12 to the optical transmission unit (free space propagation) 13, so that it is input to the optical transceiver device 7.

[0086] That is, the first transceiver separation device 6a outputs the first signal light, which is amplified by the first amplifier 5a and propagated in the optical fiber cable 12a, to the optical transmission unit (free space propagation) 13a, so that it is input to the first optical transceiver device 7a.

[0087] The second transceiver separation device 6b outputs the second signal light, amplified by the second amplifier 5b and propagating in the optical fiber cable 12b, to the optical transmission unit (free space propagation), so that it is input to the second optical transceiver device 7b.

[0088] The third transceiver separation device 6c outputs the third signal light, amplified by the third amplifier 5c and propagating in the optical fiber cable 12c, to the optical transmission unit (free space propagation), so that it is input to the third optical transceiver device 7c.

[0089] The optical transceiver 7 radiates the signal light input via the optical transmission unit 13 into space as the transmitted light.

[0090] That is, the first optical transceiver 7a radiates the first transmitted light, the second optical transceiver 7b radiates the second transmitted light, and the third optical transceiver 7c radiates the third transmitted light.

[0091] In this way, the first transmitted light from the first optical transceiver 7a, the second transmitted light from the second optical transceiver 7b, and the third transmitted light from the third optical transceiver 7c radiate in different directions in space.

[0092] On the other hand, the transmitted light is scattered by the target. This scattered light is collected by the optical transceiver 7 and then transmitted as received light to the transceiver separation device 6 via the optical transmission unit (free space propagation) 13.

[0093] The transceiver separation device 6 outputs the received light from the optical transceiver device 7, which is propagated in the optical transmission unit (free space propagation) 13, to the optical fiber cable 14, so that it is input to the signal processing device 8.

[0094] That is, the first transceiver separation device 6a outputs the first received light from the first optical transceiver device 7a, which is propagated in the optical transmission unit (free space propagation) 13a, to the optical fiber cable 14a, so that it is input to the signal processing device 8.

[0095] The second transceiver separation device 6b outputs the second received light from the second optical transceiver device 7b, which is propagated in the optical transmission unit (free space propagation) 13b, to the optical fiber cable 14b, so that it is input to the signal processing device 8.

[0096] The third transceiver separation device 6c outputs the third received light from the third optical transceiver device 7c, which is propagated in the optical transmission unit (free space propagation) 13c, to the optical fiber cable 14c, so that it is input to the signal processing device 8.

[0097] The signal processing device 8 analyzes the received light from the optical transceiver 7 transmitted via the optical fiber cable 14, the transceiver separation device 6 and the optical transmission unit (free space propagation) 13, and the local oscillation light from the demultiplexer 3 transmitted via the optical fiber cable 10b, and calculates the distance to the target existing in space and the properties of the target.

[0098] As described above, the lidar structure obtained by combining multiple optical transceivers and the switching of illumination direction based on optical switches can achieve measurement in multiple directions while suppressing device size and cost and ensuring reliability. On the other hand, although the signal-to-noise ratio (SN ratio) decreases due to scattering in the optical switches, the lidar device of Embodiment 1 provides corresponding amplifiers 5a-5c and transceiver splitters 6a-6c for each of the multiple optical transceivers 7a-7c. A distributor 4 that outputs signal light for each optical transceiver 7a-7c is arranged in front of the amplifiers 5a-5c. Therefore, in the receiving system from the optical transceivers 7a-7c to the signal processing device 8 via the transceiver splitters 6a-6c, the possibility of backscattered light generated by the scattering of the signal light by the distributor 4 is eliminated, and it will not be input to the signal processing device 8. Therefore, the decrease in the SN ratio of the received signal can be suppressed.

[0099] Furthermore, when using optical switches and amplifiers, if the backscattered light generated by the optical switch is incident on the amplifier, the amplifier's energy will be consumed due to the amplification of the backscattered light, and the proportion of energy used to amplify the transmitted light will decrease.

[0100] However, since the lidar device of embodiment 1 has a distributor 4 arranged in front of the amplifiers 5a to 5c, the backscattered light generated by the distributor 4 will not be input to the amplifiers 5a to 5c, and the amplification rate of the amplifiers 5a to 5c can be maintained at a high level.

[0101] Furthermore, it is possible to keep the light intensity input to the distributor 4 low while maintaining a high output intensity, and it is possible to use a light switch with low light resistance as the distributor 4.

[0102] Implementation method 2.

[0103] based on Figure 2 The lidar device of Embodiment 2 will be described.

[0104] exist Figure 2 In, with Figure 1 The same labels in the text indicate the same or equivalent parts.

[0105] Compared with the lidar device of embodiment 1, the lidar device of embodiment 2 has a preamplifier 15 arranged between the demultiplexer 3 and the distributor 4 that constitute the demultiplexer / distributor 2, which amplifies the signal light distributed by the demultiplexer 3.

[0106] The same effect as that of the lidar device in Embodiment 1 is obtained in the lidar device of Embodiment 2.

[0107] Furthermore, by configuring the preamplifier 15, the effects of attenuation accompanying interference and propagation can be suppressed, and a stable amplification rate and improved SN ratio can be obtained in amplifiers 5a to 5c.

[0108] Implementation method 3.

[0109] based on Figure 3 The lidar device of Embodiment 3 will be described.

[0110] exist Figure 3 In, with Figure 1 The same labels in the text indicate the same or equivalent parts.

[0111] Compared to the lidar device of Embodiment 1, the lidar device of Embodiment 3 has an optical modulator 16 disposed between the wavelength divider 3 and the distributor 4 constituting the wavelength divider / distributor 2. The optical modulator 16 is, for example, an LN (lithium niobate, LiNbO3) modulator that applies optical modulation in time to the signal light distributed by the wavelength divider 3.

[0112] In the lidar device of embodiment 3, the same effect as that of the lidar device of embodiment 1 is also obtained.

[0113] Furthermore, by configuring the optical modulator 16, high peak energy is first obtained through pulsed modulation, improving the SN ratio, and secondly, heterodyne detection can be used through frequency modulation.

[0114] Implementation method 4.

[0115] based on Figure 4 and Figure 5 The lidar device of Embodiment 4 will be described.

[0116] exist Figure 4 and Figure 5 In, with Figure 1 The same labels in the text indicate the same or equivalent parts.

[0117] The lidar device of Embodiment 4 differs from the lidar device of Embodiment 1 in that the transceiver splitter 6 is equipped with a numerical aperture converter 22, and also in that the transceiver splitter 6 equipped with the numerical aperture converter 22 is used to determine that LMA fiber is used as the fiber optic cable 12 for optically coupling the amplifier 5 to the transceiver splitter 6.

[0118] The other structural components in the lidar device of embodiment 4 are the same as those in the lidar device of embodiment 1.

[0119] Specifically, the light source 1, wave demultiplexer 3, distributor 4, multiple optical transceivers 7, and signal processing device 8 in the lidar device of embodiment 4 are the same as those in the lidar device of embodiment 1.

[0120] The lidar device in embodiment 4 uses LMA fiber as the fiber optic cable 12 for optically coupling the amplifier 5 and the transceiver splitter 6. Therefore, it is possible to suppress the nonlinear phenomena caused by the optical transmission medium in the range of maximum light intensity and maximum intensity density from the amplifier 5 to the transceiver splitter 6, especially to suppress the optical loss during transmission caused by stimulated Brillouin scattering.

[0121] Amplifier 5 uses solid-state laser amplifiers such as LMA fiber amplifiers or slab amplifiers.

[0122] Furthermore, the optical fiber cable 14 that optically couples the transceiver splitter 6 and the signal processing device 8 can be used for optical transmission at a relatively low intensity. Therefore, by using conventional optical fiber instead of LMA fiber, i.e., optical fiber with a smaller effective cross-sectional area for the basic mode than LMA fiber, a cost reduction is achieved.

[0123] Fiber optic cable 14 may also use LMA fiber depending on the required beam quality or cost.

[0124] Similarly, regarding the optical fiber cable 9 that optically couples the light source 1 to the demultiplexer 3, the optical fiber cable 10a that optically couples the demultiplexer 3 to the distributor 4, the optical fiber cable 10b that optically couples the demultiplexer 3 to the signal processing device 8, and the optical fiber cable 11 that optically couples the distributor 4 to the amplifier 5, which can be used as optical transmission cables with relatively low intensity, cost reduction is achieved by also using optical fiber cables that utilize ordinary optical fibers.

[0125] Fiber optic cables 10a, 10b, 11, and 14 can also use LMA fiber depending on the required beam quality or cost.

[0126] In addition, the optical coupling between the transceiver separation device 6 and the optical transceiver device 7 is achieved through free space propagation (optical transmission unit 13).

[0127] The LMA fiber used in fiber optic cable 12 and the conventional fiber used in fiber optic cable 14 are optical transmission units with different effective cross-sectional areas, i.e., different numerical apertures, for the basic mode.

[0128] Therefore, the transceiver separation device 6 includes: a separator having a signal optical system optical path and a receiving optical system optical path, the signal optical system optical path outputting the signal light from the amplifier 5 propagating in the optical fiber cable 12 to the optical transmission unit (free space propagation) 13, so as to input the signal light to the optical transceiver 7, and the receiving optical system optical path outputting the received light from the optical transceiver 7 propagating in the optical transmission unit (free space propagation) 13 to the optical fiber cable 14, so as to input the received light to the signal processing device 8; and a numerical aperture converter 22, which, together with the separator, performs different numerical aperture conversions in the signal optical system optical path and the receiving optical system optical path.

[0129] That is, such as Figure 5 As shown, the transceiver separation device 6 is an optical circulator consisting of a polarization beam splitter (PBS) 19, a lens 20, a 1 / 4λ wavelength plate 21, and a numerical aperture converter 22.

[0130] A splitter consisting of a polarization beam splitter 19, a lens 20, and a 1 / 4λ wavelength plate 21 forms a signal optical system optical path and a receiving optical system optical path. The signal optical system optical path outputs the signal light, amplified by the corresponding amplifier 5 and propagating in the optical fiber cable 12, to the optical transmission unit 13, so that the signal light is input to the corresponding optical transceiver 7. The receiving optical system optical path outputs the received light from the corresponding optical transceiver 7 propagating in the optical transmission unit 13 to the optical fiber cable 14, so that the received light is input to the signal processing device 8.

[0131] One end of the fiber optic cable 12 is optically coupled to the polarization beam splitter 19.

[0132] One end of the fiber optic cable 14 is optically coupled to the numerical aperture converter 22.

[0133] The polarization beam splitter 19, lens 20, and 1 / 4λ wavelength plate 21 that constitute the splitter are configured to convert the numerical aperture of the optical fiber cable 12 to the numerical aperture of the optical transceiver 7.

[0134] That is, in the optical path of the signal optical system of the transceiver separation device 6, the signal light propagating in the optical fiber cable 12 is converted from the numerical aperture of the optical fiber cable 12, which is an LMA fiber, to the numerical aperture of the optical transceiver device 7 through the polarization beam splitter 19, lens 20 and 1 / 4λ wavelength plate 21, and is output to the optical transmission unit 13.

[0135] On the other hand, in the optical path of the receiving optical system of the transceiver separation device 6, the received light from the optical transceiver device 7 propagating in the optical transmission unit 13 is converted from the numerical aperture of the optical transceiver device 7 to the numerical aperture of the LMA optical fiber through the 1 / 4λ wavelength plate 21, lens 20 and polarization beam splitter 19, and then converted from the numerical aperture of the LMA optical fiber to the numerical aperture of the optical fiber cable 14, which is a normal optical fiber, through the numerical aperture converter 22, and is output to the optical fiber cable 14, so as to be input to the signal processing device 8.

[0136] The numerical aperture converter 22 is a numerical aperture conversion lens.

[0137] Therefore, through the transceiver separation device 6, the signal light propagating from the optical fiber cable 12 is converted from the numerical aperture of the optical fiber cable 12 (which is an LMA fiber) to the numerical aperture of the optical transceiver device 7 via the polarization beam splitter 19, lens 20, and 1 / 4λ wavelength plate 21, and is output to the optical transmission unit 13, so that it is input to the optical transceiver device 7.

[0138] Furthermore, via the transceiver separation device 6, when the optical transceiver device 7 receives the received light, the received light from the optical transceiver device 7, which is propagated via the optical transmission unit 13, is converted from the numerical aperture of the optical transceiver device 7 to the numerical aperture of the LMA fiber via the 1 / 4λ wavelength plate 21-lens 20-polarization beam splitter 19-numerical aperture converter 22, and then converted from the numerical aperture of the LMA fiber to the numerical aperture of the fiber optic cable 14, which is a normal optical fiber, and output to the fiber optic cable 14, so that it is input to the signal processing device 8.

[0139] Next, the actions will be explained.

[0140] The basic operation is the same as that of the lidar device shown in Embodiment 1. Therefore, the explanation will focus on the operation of the transceiver separation device 6.

[0141] The signal light, amplified by the amplifier and propagating in the optical fiber cable, is converted from the numerical aperture of the optical fiber cable 12 (which is an LMA fiber) to the numerical aperture of the optical transceiver 7 in the transceiver separation device 6 by the polarization beam splitter 19, lens 20, and 1 / 4λ wavelength plate 21. It is then output to the optical transmission unit 13, so that it is input to the optical transceiver 7.

[0142] On the other hand, when the optical transceiver 7 receives the received light, the received light from the optical transceiver 7 propagating in the optical transmission unit 13 is converted from the numerical aperture of the optical transceiver 7 to the numerical aperture of the LMA fiber through the 1 / 4λ wavelength plate 21-lens 20-polarization beam splitter 19. Then, through the numerical aperture converter 22, it is converted from the numerical aperture of the LMA fiber to the numerical aperture of the fiber optic cable 14, which is a normal fiber, and is output to the fiber optic cable 14, so that it is input to the signal processing device 8.

[0143] As described above, the same effect as that of the lidar device in Embodiment 1 is obtained in the lidar device of Embodiment 4. In addition, since the fiber optic cable 12 is made of LMA fiber, optical loss is suppressed during the transmission of optical signals from the amplifier 5 to the transceiver splitter 6. Since the transceiver splitter 6 is configured to perform different numerical aperture conversions for the transmitted light and the received light, it is possible to prevent optical loss caused by the inconsistency of numerical aperture when the transmitted light is input to the transceiver splitter 6 and the received light is input to the fiber optic cable 14. As a result, the decrease in the SN ratio is suppressed.

[0144] Furthermore, by utilizing the difference in numerical aperture between optical fiber cable 12 and optical fiber cable 14, it is possible to prevent light loss caused by the inconsistency in numerical aperture when transmitting light to transceiver device 6 and receiving light to optical fiber cable 14.

[0145] Furthermore, by incorporating a numerical aperture converter 22 in the transceiver separation device 6, the number of components can be reduced, and combinations of various numerical aperture optical transceivers 7a-7c, optical transmission units 9-12, 14, and amplifiers 5a-5c can be employed, thus increasing design freedom.

[0146] In addition, in the lidar device of embodiment 4, it is shown that the numerical aperture converter 22 is arranged between the polarization beam splitter 19 and the fiber optic cable 14, but the numerical aperture converter 22 can also be arranged between the fiber optic cable 12 and the polarization beam splitter 19.

[0147] In this case, the numerical aperture converter 22 employs a numerical aperture conversion lens that converts the numerical aperture of the fiber optic cable 12, which is an LMA fiber, into the numerical aperture of the optical transceiver 7.

[0148] In addition, numerical aperture converters 22 can also be configured between polarization beam splitter 19 and fiber optic cable 14, and between fiber optic cable 12 and polarization beam splitter 19.

[0149] In this case, the numerical aperture converter 22 configured between the fiber optic cable 12 and the polarization beam splitter 19 employs a numerical aperture conversion lens that converts the numerical aperture of the fiber optic cable 12, which is an LMA fiber, into the numerical aperture of the optical transceiver 7, and the numerical aperture converter 22 configured between the polarization beam splitter 19 and the fiber optic cable 14 employs a numerical aperture conversion lens that converts the numerical aperture of the optical transceiver 7 into the numerical aperture of the fiber optic cable 14, which is a normal optical fiber.

[0150] Alternatively, the first optical transceiver 7a to the third optical transceiver 7c can be configured as optical transceivers with different numerical apertures, which can provide appropriate resolution according to the measurement distance.

[0151] Implementation method 5.

[0152] based on Figure 6 The lidar device of Embodiment 5 will be described.

[0153] exist Figure 6 In, with Figure 1 The same labels in the text indicate the same or equivalent parts.

[0154] Compared to the lidar device of embodiment 1, in embodiment 5, the lidar device of embodiment 1 has its wave demultiplexer 3 and distributor 4 arranged in the order of wave demultiplexer 3-distributor 4 and optically coupled through fiber optic cable 10a. In contrast, in embodiment 5, the lidar device of embodiment 5 has its wave demultiplexer 3 and distributor 4 arranged in the order of distributor 4-multiple wave demultiplexers 3 and optically coupled through fiber optic cable 24.

[0155] Wavelength divider / splitter 2, like the wavelength divider / splitter 2 in the lidar device of Embodiment 1, receives the laser light output from the light source 1 and outputs local oscillation light and multiple signal lights.

[0156] The splitter 4, which constitutes the wavelength division multiplexer 2, divides the laser emitted from the light source 1 and transmitted via the fiber optic cable 9 into multiple lasers for output. That is, the splitter 4 divides the laser transmitted via the fiber optic cable 9 into three lasers for output. The first laser is input to the first wavelength division multiplexer 3a via the fiber optic cable 24a, the second laser is input to the second wavelength division multiplexer 3b via the fiber optic cable 24b, and the third laser is input to the third wavelength division multiplexer 3c via the fiber optic cable 24c.

[0157] Distributor 4 is the same distributor as the distributor 4 in the lidar device of embodiment 1.

[0158] The wavelength divider 3, which constitutes the wavelength divider / splitter 2, splits the laser output from the splitter 4 into a local oscillation beam and a signal beam. The splitting ratio of the signal beam to the local oscillation beam is, for example, 9:1.

[0159] The first demultiplexer 3a splits the first laser beam, which has been distributed by the splitter 4 and transmitted via fiber optic cable 24a, into a first signal beam and a first local oscillation beam. The first signal beam is input to the first amplifier 5a via fiber optic cable 25a, and the first local oscillation beam is input to the signal processing device 8 via fiber optic cable 26a.

[0160] The second splitter 3b divides the second laser beam, which has been distributed by the splitter 4 and transmitted via fiber optic cable 24b, into a second signal beam and a second local oscillation beam. The second signal beam is input to the second amplifier 5b via fiber optic cable 25b, and the second local oscillation beam is input to the signal processing device 8 via fiber optic cable 26b.

[0161] The third splitter 3c divides the third laser beam, which has been distributed by the distributor 4 and transmitted via fiber optic cable 24c, into a third signal beam and a third local oscillation beam. The third signal beam is input to the third amplifier 5c via fiber optic cable 25c, and the third local oscillation beam is input to the signal processing device 8 via fiber optic cable 26c.

[0162] The first wave demultiplexer 3a to the third wave demultiplexer 3c are the same wave demultiplexers as wave demultiplexer 3 in the lidar device of Embodiment 1.

[0163] In the transmission mode, the signal processing device 8 operates in the same manner as the signal processing device 8 in the lidar device of Embodiment 1. In the reception mode, it analyzes the first received light based on the scattered light from the target and the first local oscillation light from the first wave demultiplexer 3a received by the first optical transceiver 7a, the second received light based on the scattered light from the target and the second local oscillation light from the second wave demultiplexer 3b received by the second optical transceiver 7b, and the third received light based on the scattered light from the target and the third local oscillation light from the third wave demultiplexer 3c received by the third optical transceiver 7c, and calculates the distance to the target and the properties of the target.

[0164] The same effect as that of the lidar device in Embodiment 1 is obtained in the lidar device of Embodiment 5.

[0165] The sequence from distributor 4 to first splitter 3a to third splitter 3c is adopted in the wave demultiplexer / splitter 2, thus making the mechanical configuration within the lidar device more flexible.

[0166] Furthermore, in the lidar device of embodiment 5, since the first to third lasers distributed by the distributor 4 are obtained by simple intensity division, it is also possible that the first to third signal lights after being divided by the first to third wave splitters 3a to 3c are simultaneously and in parallel amplified by the first amplifier 5a to the third amplifier 5c, respectively. The signal processing device 8 is configured to have a first signal processing device that analyzes based on the first received light and the first local oscillation light, a second signal processing device that analyzes based on the second received light and the second local oscillation light, and a third signal processing device that analyzes based on the third received light and the third local oscillation light. The first to third signal processing devices perform analysis simultaneously and in parallel to calculate the distance to the target and the properties of the target.

[0167] By configuring it in this way, it has the advantage of being able to simultaneously measure multiple different directions at the same wavelength using the first optical transceiver 7a to the third optical transceiver 7c.

[0168] In addition, the signals distributed from the distributor 4 are not limited to the three signal lights from the first signal light to the third signal light, but can also be two or more signal lights. In this case, a signal processing device 8 can be set up corresponding to each of the multiple signal lights.

[0169] Implementation method 6.

[0170] based on Figure 7 The lidar device of Embodiment 6 will be described.

[0171] exist Figure 7 In, with Figure 1 The same labels in the text indicate the same or equivalent parts.

[0172] The lidar device of Embodiment 6 differs from the lidar device of Embodiment 1 in that it is configured to have an excitation light source 27 and an excitation light demultiplexer 28 that branches the output light from the excitation light source 27, and the amplifiers 5 are excited by the excitation light branched from the excitation light demultiplexer 28.

[0173] Furthermore, in the lidar device of Embodiment 6, the following is specifically explained: an erbium-doped fiber amplifier (hereinafter referred to as EDFA) is used as amplifier 5, and a cascaded Raman fiber laser (hereinafter referred to as CRFL) is used as excitation light source 27 for providing excitation light to amplifier 5.

[0174] The cascaded Raman fiber laser 27, which serves as the excitation source, is a source that outputs single-mode laser light in the 1.48 μm band.

[0175] The EDFA has a wide gain in the 1.5μm band and is most efficiently excited by light at 1.48μm.

[0176] Therefore, when the laser output from the light source 1 is split by the demultiplexer 3 and then distributed by the distributor 4, the signal light is in the 1.5μm band. By using an EDFA on the amplifier 5 and a CRFL on the excitation light source 27, the signal light in the eye-safe band can be amplified with high intensity and high efficiency.

[0177] In addition, if the amplifier 5 is designed for high output, it is preferable to use an erbium-doped fiber amplifier (LMA-EDFA) of the LMA fiber type as amplifier 5.

[0178] The laser output from the excitation light source 27 is divided into multiple excitation beams by the excitation beam demultiplexer 28, and the divided excitation beams are input to the amplifier 5.

[0179] That is, the excitation light demultiplexer 28 divides the laser transmitted from the excitation light source 27 via the optical fiber cable 29 into the first excitation light to the third excitation light and outputs them.

[0180] The first excitation light is input to the first amplifier 5a via fiber optic cable 30a, the second excitation light is input to the second amplifier 5b via fiber optic cable 30b, and the third excitation light is input to the third amplifier 5c via fiber optic cable 30c.

[0181] The distribution of the excitation light in the excitation light splitter 28 can also be a simple branch of equal intensity, or it can be controlled to excite the amplifier 5 when the signal light is input to the amplifier 5 synchronously with the distributor 4.

[0182] In the lidar device of Embodiment 6, the basic operation is the same as that in the lidar device of Embodiment 1, except that EDFA is used for amplifier 5 and CRFL is used for excitation light source 27 to amplify the signal light in the 1.5μm band with high intensity, so the description is omitted.

[0183] As described above, the lidar device of embodiment 6 uses an excitation light splitter 28 to share the excitation light from the excitation light source 27 with multiple amplifiers 5, thus enabling the reduction of the cost and size of the lidar device.

[0184] Furthermore, the lidar device in Embodiment 6 sets the signal light from the light source 1 to the 1.5μm band, which is a safe band for the human eye, and uses an EDFA that can amplify the 1.5μm band for the amplifier 5. Therefore, it can perform high-output operation outdoors.

[0185] Furthermore, in Embodiment 6, the lidar device sets the signal light from the light source 1 to the 1.5μm band, uses an EDFA for the amplifier 5, and uses an excitation light splitter 28 to allow multiple amplifiers 5 to share the excitation light from the excitation light source 27. Therefore, even if a CRFL is used as the excitation light source 27 in the 1.48μm band in the excitation of the EDFA, the amplifier 5 can be amplified efficiently while performing high output operation outdoors, thus reducing the cost and size of the lidar device.

[0186] Furthermore, the same effect as that of the lidar device in Embodiment 1 is obtained in the lidar device of Embodiment 6.

[0187] That is, firstly, since the excitation light from a single excitation source 27 is branched by the excitation light demultiplexer 28 and the branched excitation light is input to multiple amplifiers 5, the cost and size of the lidar device can be suppressed.

[0188] Second, by setting the signal light from light source 1 to a signal light in a band safe for the human eye and using EDFA for amplifier 5, high-output outdoor operation can be safely performed.

[0189] Third, the signal light from the light source 1 is set to a signal light in a band safe for the human eye, and an EDFA is used for the amplifier 5. The excitation light source 27 of the 1.48μm band CRFL is used in combination with the EDFA. Thus, by efficiently exciting the 1.5μm band signal light, high output operation can be performed as a device capability.

[0190] Fourth, the signal light from the light source 1 is set as the signal light in the eye-safe band. The CRFL excitation light source 27 is used in combination with the amplifier 5 of the EDFA. The laser output from the excitation light source 27 is divided into multiple excitation lights by the excitation light splitter 28 and input to multiple amplifiers 5a to 5c. Thus, the excitation light source 27 can be shared by multiple amplifiers 5a to 5c, that is, it can be unified. Therefore, it can be used outdoors, and the cost and size are reduced to obtain a lidar device that can amplify the signal light in the eye-safe band with high output and high efficiency.

[0191] In summary, even if a CRFL (Cyclotron-Doped Fiber Laser) is used as the excitation source 27, which modifies the wavelength of a laser such as a YDFL through stimulated Raman scattering and outputs a high-cost single-mode laser in the 1.48 μm band with a multi-stage structure, the excitation source 27 can be shared by multiple amplifiers 5a to 5c by using an excitation light splitter 28. That is, a single excitation source 27 can be used. Therefore, the cost and size of the excitation source 27 can be reduced, and the size and cost of the lidar device can be reduced.

[0192] In addition, the lidar device of embodiment 6 uses an excitation light splitter 28 to input the excitation light output from the excitation light source 27 to all of the amplifiers 5, that is, all of the first amplifiers 5a to the third amplifiers 5c. However, when there is at least one combination of the amplifiers 5 of the EDFA and the excitation light source 27 of the CRFL, the excitation light output from the excitation light source 27 can also be input to at least one of the multiple amplifiers 5a to 5c.

[0193] Furthermore, the lidar device of embodiment 6 uses an EDFA for amplifier 5 and a CRFL for excitation light source 27, but the combination of amplifier 5 and excitation light source 27 is not limited to this, and any combination of amplifier 5 and excitation light source 27 can be used according to the design.

[0194] Furthermore, it is possible to freely combine the various embodiments, or to modify any structural elements of the various embodiments, or to omit any structural elements in each embodiment.

[0195] Industrial utilization

[0196] The lidar device disclosed herein is suitable for Doppler lidar devices for anemometer measurement, lidar devices for three-dimensional high-speed imaging, and lidar devices for gas concentration measurement.

[0197] Explanation of reference numerals in the attached figures

[0198] 1 Light source, 2 Wavelength divider / splitter, 3 Wavelength divider, 4 Splitter, 5a-5c Amplifier, 6a-6c Transceiver separation device, 7a-7c Optical transceiver device, 8 Signal processing device, 15 Preamplifier, 16 Optical modulator, 22a-22c Numerical aperture converter, 27 Excitation light source, 28 Excitation optical wavelength divider.

Claims

1. A lidar device, wherein, The lidar device includes: A light source that outputs laser light of a single wavelength; Wavelength divider / splitter, which receives laser light output from the light source and outputs localized oscillating light and multiple signal lights; Multiple amplifiers, each corresponding to a multiple signal light output from the wavelength division / distributor, amplify the corresponding signal light; Multiple optical transceivers are configured to radiate in different directions from each other and correspond to the multiple amplifiers respectively. They radiate signal light output from the corresponding amplifiers into space as transmitted light and receive scattered light from the measurement target existing in the space based on the radiated transmitted light as received light. A signal processing device that calculates the distance to the target and the properties of the target based on received light from the plurality of optical transceivers and local oscillating light from the wavelength division / splitter. as well as Multiple transceiver separation devices are provided, each corresponding to one of the multiple amplifiers and one of the multiple optical transceivers, which couple the transmitted light from the multiple amplifiers to the corresponding optical transceivers and couple the received light from the multiple optical transceivers to the corresponding signal processing device. in, The wavelength division / splitter has: A wavelength division multiplexer (WDM) splits the laser light output from the light source into a local oscillation beam and a signal beam; and A distributor that distributes the signal light from the demultiplexer into multiple signal lights and outputs them. The distributor is an optical switch and is located in the preamplifier stage of multiple amplifiers.

2. The lidar device according to claim 1, wherein, The lidar device includes a preamplifier that amplifies the signal light from the splitter and outputs it to the splitter.

3. The lidar device according to claim 1, wherein, The lidar device includes a modulator that modulates the signal light from the wave splitter and outputs it to the splitter.

4. The lidar device according to claim 1, wherein, The laser output from the light source has a wavelength within the eye-safe range.

5. The lidar device according to claim 2, wherein, The laser output from the light source has a wavelength within the eye-safe range.

6. The lidar device according to claim 3, wherein, The laser output from the light source has a wavelength within the eye-safe range.

7. The lidar device according to any one of claims 1 to 6, wherein, The plurality of transceiver separation devices each have: A splitter has a signal optical system path and a receiving optical system path. The signal optical system path outputs the signal light amplified by the corresponding amplifier and propagating in the optical fiber cable to the optical transmission unit, so that the signal light is input to the corresponding optical transceiver. The receiving optical system path outputs the received light from the corresponding optical transceiver propagating in the optical transmission unit to the optical fiber cable, so that the received light is input to the signal processing device. as well as A numerical aperture converter, together with the separator, performs different numerical aperture conversions in the optical paths of the signal optical system and the receiving optical system.

8. The lidar device according to claim 7, wherein, The numerical aperture converter is disposed between the separator and the optical fiber cable that transmits the received light to the signal processing device. The splitter converts the numerical aperture of the optical fiber cable through which the signal light from the amplifier propagates radially to the numerical aperture of the optical transceiver. The splitter converts the numerical aperture of the fiber optic cable from which the signal light from the amplifier is radially propagated from the numerical aperture of the optical transceiver. The numerical aperture converter then converts the numerical aperture of the fiber optic cable, which has been converted by the splitter to propagate the signal light from the amplifier, into the numerical aperture of the fiber optic cable that propagates the received light to the signal processing device.

9. The lidar device according to claim 7, wherein, The fiber optic cable that transmits the signal light from the amplifier is an LMA fiber optic cable. The fiber optic cable that transmits the received light to the signal processing device is a fiber optic cable that uses an optical fiber with an effective cross-sectional area smaller than that of LMA fiber for the basic mode.

10. The lidar device according to claim 8, wherein, The fiber optic cable that transmits the signal light from the amplifier is an LMA fiber optic cable. The fiber optic cable that transmits the received light to the signal processing device is a fiber optic cable that uses an optical fiber with an effective cross-sectional area smaller than that of LMA fiber for the basic mode.

11. The lidar device according to any one of claims 1 to 6 or 8 to 10, wherein, The lidar device has an excitation light source that outputs excitation light to at least one of the plurality of amplifiers.

12. The lidar device according to claim 7, wherein, The lidar device has an excitation light source that outputs excitation light to at least one of the plurality of amplifiers.

13. The lidar device according to any one of claims 1 to 6 or 8 to 10, wherein, The lidar device includes: Excitation light source, which outputs excitation light; and An excitation light demultiplexer that distributes the excitation light output from the excitation light source and outputs the excitation light distributed to at least one of the plurality of amplifiers.

14. The lidar device according to claim 7, wherein, The lidar device includes: Excitation light source, which outputs excitation light; and An excitation light demultiplexer that distributes the excitation light output from the excitation light source and outputs the excitation light distributed to at least one of the plurality of amplifiers.

15. The lidar device according to claim 11, wherein, The excitation light source has a cascaded Raman fiber laser. Each of the multiple amplifiers has an erbium-doped fiber amplifier.

16. The lidar device according to claim 12, wherein, The excitation light source has a cascaded Raman fiber laser. Each of the multiple amplifiers has an erbium-doped fiber amplifier.

17. The lidar device according to claim 13, wherein, The excitation light source has a cascaded Raman fiber laser. Each of the multiple amplifiers has an erbium-doped fiber amplifier.

18. The lidar device according to claim 14, wherein, The excitation light source has a cascaded Raman fiber laser. Each of the multiple amplifiers has an erbium-doped fiber amplifier.

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