Imaging System with Improved Scanning Speed

Abstract

The LIDAR system includes a signal guiding unit that can guide the emitted LIDAR signal to any one of a plurality of different alternative waveguides. Each of the alternative waveguides is associated with a different switch channel, characterized in that an optical signal including light from the emitted LIDAR signal guided to that particular one transmits through the switch channel associated with that alternative waveguide. The LIDAR system is configured to output a system output signal including light from the emitted LIDAR signal. The system output signal transmits through different switch channels. The LIDAR system is configured to receive a system feedback signal including light from one of the system output signals after an object outside the system receives and reflects the system output signal. The signal combining unit generates different composite signals by combining the light from the system feedback signals transmitting through different switch channels with a reference signal. The electronic device calculates LIDAR data from one or more frequencies of the composite signals. The LIDAR system is configured to continue generating a composite signal transmitting through the first switch channel for a substantially constant period even after the imaging system stops outputting the system output signal transmitting through the first one of the switch channels.

Description

Related Applications

[0001] This application is a continuation of U.S. Patent Application Serial No. 17 / 861,162, entitled "Imaging System with Improved Scan Speed," filed on July 8, 2022, the entire disclosure of which is incorporated herein by reference. Field

[0002] The present invention relates to an optical device, specifically a LIDAR system. Background

[0003] As optical imaging systems support an increasing number of applications, the requirements for their functions are rising. Optical imaging systems generally generate data in a series of sample regions sequentially irradiated by a system output signal. The data of the sample regions indicates the radial velocity and / or distance between the imaging system and one or more objects located within the sample regions. The imaging system can scan the system output signal to a plurality of different sample regions. The sample regions can be joined together to form the field of view of the imaging system. As a result, a combination of data from different sample regions provides data of the objects within the field of view.

[0004] Increasing the speed at which LIDAR data can be generated for different sample regions can increase the frequency at which the field of view can be scanned and / or increase the resolution of the field of view. As a result, improving the generation speed of LIDAR data can increase the number of applications in which the LIDAR system can be successfully applied. However, improving the generation speed of LIDAR data often increases the complexity and / or cost of the LIDAR system. As a result, there is a need for improvement in LIDAR systems. Summary

[0005] The LIDAR system includes a signal guiding unit that can guide the emitted LIDAR signal to any one of a plurality of different alternative waveguides. Each of the alternative waveguides is associated with a different switch channel in that the optical signal including the light from the emitted LIDAR signal guided to that particular one is characterized as transmitting through the switch channel associated with that alternative waveguide. The LIDAR system is configured to output a system output signal including the light from the emitted LIDAR signal. The system output signal transmits through different switch channels. The LIDAR system is configured to receive a system feedback signal including the light from one of the system output signals after an object outside the system receives and reflects the system output signal. The signal combining unit generates different composite signals by combining the light from the system feedback signals transmitting through different switch channels with a reference signal. The electronic device calculates LIDAR data from one or more frequencies of the composite signals. The LIDAR system is configured to continue generating a composite signal transmitting through the first switch channel for a substantially constant period even after the imaging system stops outputting the system output signal transmitting through the first one of the switch channels.

Brief Description of the Drawings

[0006] FIG. 1 shows an imaging system including a chip having a photonic circuit.

[0007] FIG. 2 shows a light source including a plurality of laser sources.

[0008] FIG. 3 is a schematic diagram of an imaging system including a plurality of different cores on a chip.

[0009] FIG. 4A is a frequency-versus-time schedule for adjusting wavelength channels in a system output signal.

[0010] FIG. 4B is an enlarged version of the frequency-versus-time schedule shown in FIG. 4A, showing only a part of one of the chirp cycles shown in FIG. 4A.

[0011] Figures 5A and 5B show an example of a signal processing unit suitable for use as a signal processing unit in a LIDAR system constructed according to FIG. 1. FIG. 5A is a schematic diagram of an example of a suitable optoelectronic assembly for use in the signal processing unit.

[0012] FIG. 5B provides a schematic diagram of the relationship between the electronic device and the optoelectronic assembly of FIG. 5A.

[0013] FIG. 5C shows a part of an electronic device including components from a plurality of different signal processing units.

[0014] FIG. 6A is a schematic diagram of the relationship between a LIDAR system including a single LIDAR core (not shown) and the field of view.

[0015] FIG. 6B is a side view of the virtual plane from FIG. 6A.

[0016] FIG. 6C is another possible side view of the virtual plane from FIG. 6A.

[0017] FIG. 7 is a cross-sectional view of a silicon-on-insulator wafer.

[0018] Figures 8A and 8B show an example of an optical switch including a cascaded Mach-Zehnder interferometer. FIG. 8A is a top view of the optical switch.

[0019] FIG. 8B is a cross-sectional view of the optical switch shown in FIG. 8A taken along the line labeled B in FIG. 8A.

[0020] FIG. 9 shows the LIDAR system of FIG. 3 modified to have a plurality of signal guiding parts each receiving a LIDAR output signal from a different core.

[0021] FIG. 10 shows the LIDAR system of FIG. 3 with the light source disposed outside the chip.

[0022] FIG. 11 shows a part of a LIDAR chip including a reference waveguide used with a beam dump. Explanation

[0023] The imaging system has a signal guiding unit that can guide the emitted LIDAR signal to any one of a plurality of different alternative waveguides. Each of the alternative waveguides can be associated with a different switch channel. An optical signal including light from the emitted LIDAR signal guided to a specific one of the alternative waveguides is characterized as transmitting through the switch channel associated with that alternative waveguide.

[0024] The system outputs a system output signal including light from the emitted LIDAR signal. As a result, the system output signal can transmit through different switch channels. In some examples, the imaging system is configured such that the direction in which the system output signal travels away from the imaging system changes according to the change of the alternative waveguide that receives the system output signal. As a result, the system output signals transmitting through different switch channels can travel in different directions away from the imaging system.

[0025] The imaging system receives a system feedback signal. Each of the system feedback signals includes light from one of the system output signals after an object located outside the system receives and reflects the system output signal. As a result, the system feedback signals transmit through different switch channels.

[0026] The imaging system generates different composite signals by combining light from the system output signals transmitting through different switch channels with a reference signal. Thus, different composite signals can transmit through different switch channels. The imaging system can include an electronic device that calculates LIDAR data from one or more frequencies of the composite signals. The LIDAR data indicates the radial velocity and / or distance between the LIDAR system and one or more objects located outside the LIDAR system and reflecting one of the system output signals.

[0027] After the imaging system stops outputting the system output signal transmitted to the first switch channel, the imaging system has the ability to generate a composite signal that is transmitted over a substantial period of time on the first of the switch channels. As a result, while the imaging system can still generate LIDAR data from the composite signal transmitted on this first switch channel, the emitted LIDAR signal can be directed to a different one of the other waveguides. Thus, while the imaging system can generate LIDAR data from the composite signal transmitted on this first switch channel, it can output a system output signal transmitted on the second of the switch channels. The ability to generate LIDAR data transmitted on one switch channel while outputting a system output signal transmitted on a different one of the switch channels reduces the period of time required for the imaging system to output a system output signal transmitted on a particular channel. Thus, this ability makes it possible to increase the frequency at which the field of view can be scanned and / or increase the resolution of this field of view.

[0028] FIG. 1 is a schematic diagram of a part of a LIDAR system including a LIDAR chip 2. FIG. 1 includes a top view of a part of the LIDAR chip 2. The LIDAR chip includes a LIDAR core 4. The LIDAR core 4 includes a photonic integrated circuit. The LIDAR core 4 includes a light source 10 such as a laser that outputs an emitted LIDAR signal. The emitted LIDAR signal includes one or more wavelength channels each having a different wavelength. When the emitted LIDAR signal transmits multiple wavelength channels, the wavelengths of the wavelength channels can be periodically spaced such that the wavelength increase from one switch channel to the next switch channel is constant or substantially constant. Suitable light sources 10 for generating multiple wavelength channels having periodically spaced wavelengths include, but are not limited to, multiple single-wavelength lasers multiplexed in a single optical waveguide, such as those described in U.S. Patent Application Serial No. 11 / 998,846, filed Nov. 30, 2017, entitled "Optical Apparatus for Multi-Switch Channels" (Patent No. 7542641), the entire disclosure of which is incorporated herein by reference.

[0029] The LIDAR chip includes a utility waveguide 12 that transmits the emitted LIDAR signal to a signal director 14. The signal director 14 is operated by electronics and can direct light from the emitted LIDAR signal to one of a plurality of different alternative waveguides 16. There are N alternative waveguides, and each of the alternative waveguides 16 is associated with an alternative waveguide index i. Here, i has values from 1 to N. Suitable values of N include, but are not limited to, values of 1, 2, or 3 or more and / or 128, 64, or 32 or less. In one example, N ranges from 1 to 128.

[0030] Each of the alternative waveguides 16 can receive the emitted LIDAR signal from the signal guiding part 14. When any one of the alternative waveguides 16 receives the emitted LIDAR signal, the alternative waveguide 16 functions as an active waveguide, and the emitted LIDAR signal passes through it and is transmitted to the port 18 that can function as a LIDAR output signal from the LIDAR chip. Therefore, the emitted LIDAR signal is output from the active waveguide. Appropriate ports include, but are not limited to, the facets of the alternative waveguide 16.

[0031] The optical signal generated from the emitted LIDAR signal guided to the alternative waveguide 16 with the alternative waveguide index i can be regarded as the optical signal transmitting through the channel (C i ). Therefore, each LIDAR output signal is associated with a different one of the alternative waveguide indices i = 1 to N. For example, the path of the LIDAR output signal transmitting through the switch channel with the alternative waveguide index N is denoted as SC N in FIG. 1. For the sake of explanation, this LIDAR system is shown as generating two LIDAR output signals (N = 2) denoted as SC1 to SC N . Each of the different LIDAR output signals can transmit through a different switch channel, and each of the different switch channels can transmit the selection of the same wavelength or a substantially the same wavelength.

[0032] The light from the LIDAR output signal travels away from the LIDAR system in the system output signal. In some examples, the portion of the LIDAR output signal emitted from the LIDAR chip can also be regarded as the system output signal. As an example, when the exit of the LIDAR output signal from the LIDAR chip is also the exit of the LIDAR output signal from the LIDAR system, the LIDAR output signal can also be regarded as the system output signal.

[0033] The system output signal can travel through the free space in the atmosphere, environment, or space where the LIDAR system is disposed. The system output signal can be reflected by one or more objects in the path of the system output signal. When the system output signal is reflected, at least a portion of the reflected light is fed back as a system feedback signal toward the LIDAR chip.

[0034] The light from the system feedback signal can be transmitted in the LIDAR input signal received by the LIDAR chip. In some examples, a portion of the system feedback signal can function as the LIDAR input signal.

[0035] The LIDAR input signal is fed back to the LIDAR chip such that the LIDAR input signal transmitting through the switch channel SC i is incident on the alternative waveguide 16 associated with the same alternative waveguide index i. As a result, LIDAR input signals transmitting through different switch channels are directed to different alternative waveguides. The portion of the LIDAR input signal incident on the alternative waveguide 16 functions as the incident LIDAR signal. As a result, the alternative waveguide receiving the incident LIDAR signal can direct the outgoing LIDAR signal while also directing the incident LIDAR signal in the opposite direction. The alternative waveguide 16 receiving the incident LIDAR signal transmits a portion of the incident LIDAR signal to the signal director 14. The signal director 14 outputs the received portion of the incident LIDAR signal onto the utility waveguide 12.

[0036] The alternative waveguide 16 transmits the incident LIDAR signal to a splitter 24 that moves a portion of the incident LIDAR signal from the alternative waveguide 16 onto the preliminary comparison waveguide 26 as a preliminary comparison signal. Suitable splitters 24 include, but are not limited to, optical couplers, y-junctions, and MMIs. In some examples, the splitter 24 is configured such that the power of the incident LIDAR signal is split evenly or substantially evenly between the utility waveguide 12 and the comparison waveguide 26.

[0037] The preliminary comparison waveguide 26 transmits a preliminary comparison signal to the comparison demultiplexer 30. When the comparison optical signal includes a plurality of wavelength channels, the comparison demultiplexer 30 divides the comparison incident LIDAR signal into different comparison signals that each transmit a different wavelength channel. The comparison demultiplexer 30 outputs the comparison signals onto different comparison waveguides 32. Each of the comparison waveguides 32 transmits one of the comparison signals to a different signal processing unit 34. Thus, the signal processing units 34 that receive comparison signals from the same comparison demultiplexer 30 each receive a comparison signal that transmits a different one of the wavelength channels.

[0038] The LIDAR chip includes a splitter 35 configured to move a portion of the emitted LIDAR signal from the utility waveguide 12 onto the reference signal waveguide 36. The portion of the emitted LIDAR signal received by the reference signal waveguide 36 functions as a reference optical signal. The reference signal waveguide 36 transmits the reference optical signal to the reference demultiplexer 38. When the reference optical signal includes a plurality of wavelength channels, the reference demultiplexer 38 divides the reference optical signal into different preliminary reference signals that each transmit a different wavelength channel. The reference demultiplexer 38 outputs the preliminary reference signals onto different reference waveguides 40. Suitable splitters 24 include, but are not limited to, wavelength-independent signal splitters such as optical couplers, Y-junctions, MMIs, evanescent optical couplers, and star couplers. Suitable reference demultiplexers 38 include, but are not limited to, optical demultiplexers such as arrayed waveguide gratings (AWGs) and Etalon gratings.

[0039] Each of the reference waveguides 40 transmits one of the preliminary reference signals to a different splitter 42. Each of the splitters 42 divides the preliminary reference signal into a plurality of different reference signals that each output onto a different reference waveguide 44. Each of the reference waveguides 44 transmits one of the reference signals to a different one of the signal processing units 34. Suitable splitters 42 include, but are not limited to, wavelength-independent signal combiners such as optical couplers, y-junctions, MMIs, cascaded evanescent optical couplers, cascaded y-junctions, and star couplers.

[0040] The comparison waveguide 32 and the reference waveguide 44 are configured such that the comparison signal and the corresponding reference signal are received by the same signal processing unit 34. For example, the comparison waveguide 32 and the reference waveguide 40 are configured such that the comparison signal and the corresponding reference signal transmitting the same wavelength channel are received by the same signal processing unit 34. Accordingly, different signal processing units 34 each receive a comparison signal and a reference signal transmitting the same wavelength channel.

[0041] Also, the comparison waveguide 32 and the reference waveguide 44 are configured such that each of the signal processing units 34 receives a comparison signal and a reference signal transmitting the same switch channel. As a result, each of the signal processing units 34 receives a comparison signal and a reference signal transmitting the same switch channel and the same wavelength channel. In some examples, the comparison waveguide 32 and the reference waveguide 44 are configured such that each of the signal processing units 34 receives a comparison signal and a reference signal having a unique combination of a switch channel and a wavelength channel. The signal processing units 34 can be arranged in different switch channel groups 64. The signal processing units 34 within the same switch channel group 64 each receive a comparison signal and a reference signal transmitting the same switch channel. For example, the signal processing units 34 within the same switch channel group 64 can receive a comparison signal and a reference signal transmitting different wavelength channels and the same switch channel C i and can receive a reference signal.

[0042] As will be described in more detail below, each of the signal processing units 34 combines the comparison signal with the corresponding reference signal to form a composite optical signal that transmits the LIDAR data of the sample region in the field of view. Accordingly, the composite optical signal can be processed to extract the LIDAR data of the sample region.

[0043] The LIDAR chip can include a control branch for controlling the operation of the light source 10. The control branch includes a directional coupler 66 that moves a portion of the emitted LIDAR signal from the utility waveguide 12 onto the control waveguide 68. The combined portion of the emitted LIDAR signal functions as a tapped signal. FIG. 1 shows the directional coupler 66 that moves a portion of the emitted LIDAR signal onto the control waveguide 68, but other signal tap portions can be used to move a portion of the emitted LIDAR signal from the utility waveguide 12 onto the control waveguide 68. Examples of suitable signal tap portions include, but are not limited to, Y-junctions and MMIs.

[0044] The control waveguide 68 transmits the tapped signal to the control unit 70. The control unit can communicate electrically with the electronic device 62. FIG. 1 shows the electronic device as a separate component from the processing unit 34, but a portion of the electronic device can be included in each of the processing units 34. During operation, the electronic device 62 can adjust the frequency of the emitted LIDAR signal in response to the output from the control unit. An example of a suitable configuration of the control unit is described in U.S. Patent Application Serial No. 15 / 977,957, titled "Optical Sensor Chip," filed on May 11, 2018, which is incorporated herein by reference in its entirety.

[0045] When the splitter 24 is an optical coupler such as a 2x2 coupler, this splitter can move a portion of the emitted LIDAR signal onto the preliminary comparison waveguide 26. The preliminary comparison waveguide 26 can optionally terminate with a beam dump 72 that receives the combined portion of the emitted LIDAR signal. A suitable beam dump 72 can be configured to scatter the combined portion of the emitted LIDAR signal without reflecting a substantial amount of light from the combined portion of the emitted LIDAR signal back into the preliminary comparison waveguide 26.

[0046] FIG. 2 shows an example of a light source 10 including a plurality of laser sources 84. In some examples, each of the laser sources 84 outputs one or more of the channels on the light source waveguide 86. The light source waveguide 86 transmits the channels to a laser multiplexer 88 that combines the channels to form an optical signal received on a channel waveguide or utility waveguide 12. Suitable laser multiplexers 88 include, but are not limited to, arrayed waveguide grating (AWG) multiplexers, echelle grating multiplexers, and star couplers. The electronic device can operate the laser sources 84 such that the laser sources 84 output each of the channels simultaneously. The electronic device can operate the laser sources 84 such that the laser sources 84 output each of the channels simultaneously.

[0047] In some examples, each of the laser sources 84 outputs one of the wavelength channels on the light source waveguide 86. As a result, each laser source 84 can be a light source of a different wavelength channel among the wavelength channels in the emitted LIDAR signal and thus in the system output signal.

[0048] The electronic device can operate the laser sources 84 independently. For example, the electronic device can operate the laser sources 84 to provide a LIDAR output signal having a specific frequency - versus - time waveform. The electronic device can operate the laser sources 84 independently, and since each laser source 84 can be a light source of a different one of the wavelength channels, the electronic device can operate the laser sources 84 such that different wavelength channels in the emitted LIDAR signal and thus in the system output signal have different frequency - versus - time waveforms.

[0049] Laser sources 84 suitable for use with the light source 10 configured according to FIG. 2 include, but are not limited to, external cavity lasers, distributed feedback lasers (DFB), and Fabry - Perot (FP) lasers. External cavity lasers are generally advantageous in this embodiment because they generally have a narrow linewidth and can reduce the noise of the detected signal.

[0050] A LIDAR system can include a LIDAR chip having one or more LIDR cores 4. As an example, FIG. 3 shows a LIDAR chip including a plurality of different cores. Each of the cores is denoted as core k and is represented as such, where k represents the exponent k. Each of the LIDAR cores can be constructed as disclosed in the context of FIG. 1 or can have an alternative structure. Each of the LIDAR cores outputs a different LIDAR output signal. The LIDAR output signal output from the core k denoted as core can be represented as S k,i where i represents the channel index. As a result, S k,i is a function of the alternative waveguide index i and the core index k. As an example, the LIDAR output signal represented as S k,i is output from core k and received by the alternative waveguide index i. Accordingly, the LIDAR output signal represented as S k,i is output from core k and transmitted through the switch channel SC i .

[0051] The LIDAR system can include an optical component assembly 75 that receives LIDAR output signals from different cores and outputs a system output signal that each includes, consists of, or consists essentially of light from a different one of the LIDAR output signals. This optical component assembly 75 can be operated by an electronic device 280, thereby steering the system output signal to different sample regions in the field of view of the LIDAR system.

[0052] Figure 3 shows an optical component assembly 75 including a signal guiding unit 76 that receives each of the LIDAR output signals. This signal guiding unit 76 changes the direction in which at least a part of the LIDAR output signal is traveling and outputs each of the LIDAR output signals as a re-guided LIDAR output signal. Suitable signal guiding units 76 include, but are not limited to, convex lenses and concave mirrors. The optical component assembly 75 includes one or more beam steering units 78 that receive the re-guided LIDAR output signal output from the signal guiding unit 76 as a system output signal. The direction in which the system output signal travels away from the LIDAR system is denoted as d2 in Figure 3. The electronic device can operate one or more beam steering units 78, thereby steering each of the system output signals to different sample regions within the field of view. As is apparent from the arrows denoted as A and B in Figure 3, one or more beam steering units 78 can be configured such that the electronic device can steer the system output signal in one or two dimensions. As a result, one or more beam steering units 78 can function as a beam steering mechanism operated by the electronic device, thereby steering the system output signal within the field of view of the LIDAR system. Suitable beam steering units 78 include, but are not limited to, movable mirrors, MEMS mirrors, optical phased arrays (OPAs), diffraction gratings, and actuated diffraction gratings. In some examples, the signal guiding unit 76 and / or one or more beam steering units 78 are configured to operate on the system output signal, whereby the system output signal is collimated or substantially collimated as it travels away from the LIDAR system. Additionally or alternatively, the LIDAR system can include one or more collimation optical components (not shown) that operate on the LIDAR output signal, the re-guided LIDAR output signal, and / or the system output signal, whereby the system output signal is collimated or substantially collimated as it travels away from the LIDAR system.

[0053] The system output signal can be reflected by an object located outside the LIDAR system. All or part of the reflected light from the system output signal can be fed back to the LIDAR system as a system feedback signal. Each of the system feedback signals is received by one or more beam steering units 78. The one or more beam steering units 78 output at least a portion of each of the system feedback signals as a feedback signal. Each of the feedback signals is received by a signal guiding unit 76. The signal guiding unit 76 outputs at least a portion of each of the feedback signals as a LIDAR input signal. Each of the different LIDAR input signals is received by a different one of the cores 4. Each of the LIDAR input signals includes or consists of light from the LIDAR output signal output from the core that receives the LIDAR input signal. Also, the LIDAR input signal received by the alternative waveguide includes or consists of light from the LIDAR output signal output from the same alternative waveguide.

[0054] One or more signal guiding units 76 can change the direction in which the LIDAR output signal moves away from the one or more signal guiding units 76, whereby the direction of the LIDAR output signal is different from that of the resulting re-guided LIDAR output signal. In some examples, the one or more signal guiding units 76 are selected such that all or a portion of the re-guided LIDAR output signal moves away from the one or more signal guiding units 76 in a non-parallel direction. As an example, in FIG. 3, the one or more signal guiding units 76 are lenses, and each of the different LIDAR output signals is incident on the lens at a different angle of incidence. As a result, each of the re-guided LIDAR output signals travels in a different direction away from the signal guiding unit 76. Further, the re-guided LIDAR output signals travel in non-parallel directions away from the signal guiding unit 76. As is apparent from FIG. 3, due to the different directions of the system output signal, the system output signal can travel in different directions away from the LIDAR system. In some examples, the system output signal travels in non-parallel directions away from the LIDAR system.

[0055] By operating the signal guiding unit 14 on the core, the location where the LIDAR output signal is received by one or more signal guiding units 76 can be changed. Thus, the direction in which the system output signal generated from that core travels away from the LIDAR system can be changed. As an example, the dashed line in FIG. 3 shows the result of operating the signal guiding unit 14 on the core, whereby this core outputs a LIDAR output signal represented by S k,i instead of the LIDAR output signal represented by S k,i+1 As is clear from FIG. 3, the operation of this signal guiding unit 14 changes the direction in which the system output signal output from core 1 travels away from the LIDAR system. As a result, the electronic device can operate the signal guiding unit 14 on different cores, thereby maneuvering the system output signal within the field of view of the LIDAR system. Thus, the electronic device can operate the signal guiding unit 14 on different cores and / or on one or more beam steering units 78, thereby maneuvering the system output signal within the field of view of the LIDAR system. A suitable method of operating the signal guiding unit 14 on different cores and / or on one or more beam steering units 78 to thereby maneuver the system output signal within the field of view of the LIDAR system is disclosed in U.S. Patent Application Serial No. 17 / 580,623, titled "Imaging System Having Multiple Cores," filed on January 20, 2022, the entire disclosure of which is incorporated herein by reference.

[0056] The optical component assembly 75 can have a configuration other than that shown in FIG. 3. For example, the one or more beam steering units 78 can be disposed between the signal guiding unit 76 and the LIDAR chip. Also, the optical component assembly 75 can include optical components not shown. For example, the optical component assembly 75 can include one or more lenses configured to increase the collimation of the LIDAR output signal and / or other signals derived from and / or including light from the LIDAR output signal.

[0057] The wavelengths of the LIDAR output signals output from different cores may be the same or different. As a result, the light sources on different cores can be configured to output emitted light signals each having a different, the same, or substantially the same wavelength selection. Thus, the wavelength selection in different system output signals can be different, the same, or substantially the same.

[0058] All or part of the electronics 62 associated with different cores may optionally be fixed within the electronics 280 shown in FIG. 3. The fixed electronics 280 may be disposed on the LIDAR chip or may be external to the LIDAR chip. The fixed electronics 280 can collect or generate LIDAR data results from different cores and / or coordinate LIDAR data results from different cores to assemble LIDAR data results for the field of view of the LIDAR system.

[0059] FIG. 3 shows four cores on the LIDAR chip, but the LIDAR chip can include one, two, or more than two cores. The appropriate number of cores on the LIDAR chip includes, but is not limited to, a number greater than 1, 2, 4, or 6 and / or less than 32, 64, or 128.

[0060] During operation of the LIDAR system, the electronics chirp the frequency of one or more wavelength channels within the system output signal. FIGS. 4A and 4B provide an example of a frequency-versus-time schedule for adjusting the wavelength channels within the system output signal. The system output signal is λ jis shown as transmitting a channel denoted as such, where j is a wavelength channel index with values from 1 to M, and in this example, M = 3. In some examples, the base frequencies of the wavelength channels are separated by Δf. This frequency is adjusted so that there is no overlap in the frequencies of different wavelength channels. The system output signals λ1 and λ2 each have a chirp frequency in that their frequencies change with time. The chirps of the system output signals λ1 and λ2 are performed for a series of chirp cycles each having a duration denoted as CP. FIG. 4B is an enlarged version of the frequency-versus-time schedule shown in FIG. 4A and shows only a portion of one of the chirp cycles shown in FIG. 4A.

[0061] At least two of the wavelength channels have frequencies that are chirped at different speeds and / or in different directions. For example, the chirps of the system output signals transmitting the wavelength channels λ1 and λ2 during a chirp cycle can be upward chirps where the frequency increases or downward chirps where the frequency decreases. The chirps of the system output signals transmitting the wavelength channels λ1 and λ2 during a chirp cycle have linear chirp segments within non-linear chirp segments. This non-linear chirp segment can be the result of changing the chirp direction at the interface between chirp cycles. The duration of the linear chirp segment is denoted as cp n in FIG. 4A, where n is a cycle index. In some examples, the duration of this linear chirp segment is longer than 5 μs, 10 μs, or 100 μs and / or less than 200 μs, 500 μs, or 1000 μs. In some examples, the duration of the linear chirp segment is longer than 5, 10, or 100 times and / or less than 200, 500, or 1000 times the total duration of one or more non-linear chirp segments included in the chirp cycle.

[0062] During the same chirp cycle, the frequency changes of the output signals transmitted through wavelength channels λ1 and λ2 are in opposite directions but at the same speed. As a result, the sample region is simultaneously irradiated by at least one wavelength channel with increasing frequency and at least one wavelength channel with the same rate of change of frequency but decreasing frequency.

[0063] The system output signal transmitting the wavelength channel denoted as λ3 is optional. The system output signal denoted as λ3 is shown at an unchirped frequency, but the system output signal transmitting λ3 can have a chirped frequency or an unchirped frequency. If the system output signal transmitting λ3 has a chirped frequency, the speed and / or direction of the frequency chirp can be different from the speed and direction of the frequency chirp of the system output signal λ1, and can also be different from the speed and direction of the frequency chirp of the system output signal λ2.

[0064] The system output signal is output during a plurality of different output periods. The composite optical signal generated in response to the output of the system output signal during the output period is used to generate LIDAR data for this output period. The LIDAR data for the output period indicates the radial velocity and / or distance between the LIDAR system and one or more objects that reflected the system output signal output during that output period. Different output periods are denoted as p in FIG. 4A k where k is an output period index with a value of 1 or more. The output periods can occur continuously. In some examples, there is no or substantially no delay between output periods that are temporally adjacent to each other within the same chirp cycle.

[0065] Each of the output periods can have the same or substantially the same duration. In some examples, the duration of the output period is longer than 1 μs, 2 μs, or 4 μs and / or less than 5 μs, 10 μs, or 100 μs. Additionally or alternatively, the duration of the linear chirp segment can be longer than 2, 5, or 10 times and / or less than 20, 100, or 200 times the duration of each of at least a portion of the output periods.

[0066] As described above, the system output signal can be steered to different sample regions within the field of view of the LIDAR system. Each of the sample regions can be associated with one of the output periods. For example, a sample region can be the volume of the field of view that is illuminated by the system output signal output during the output period associated with that sample region and that extends the maximum operating distance from the LIDAR system.

[0067] At the end of each output period, the electronics can operate the signal director 14 to switch the alternative waveguide 16 that receives the light source output signal. As a result, the switch channel transmitted by the light source output signal changes with the change in the output period. Accordingly, the switch channel transmitted by the system output signal is different for each adjacent output period. As described in the context of FIG. 3, switching the alternative waveguide 16 that receives the light source output signal and / or changing the switch channel transmitted by the system output signal changes the direction in which the system output signal travels away from the LIDAR system. As a result, the change in the output period is associated with a change in the sample region illuminated by the system output signal. Accordingly, each of the output periods is associated with a different one of the sample regions.

[0068] Referring to FIG. 1, it can be seen that after the alternative waveguide 16 that receives the light source output signal is changed and / or after the switch channels transmitted by the system output signal are changed, the signal processing unit 34 within the same switch channel group 64 continues to receive the comparison signal and the reference signal. As a result, while another alternative waveguide is receiving the light source output signal, a composite signal can be generated by the channel group 64 associated with the alternative waveguide index i. Therefore, the same core within the LIDAR system can simultaneously receive system feedback signals transmitting different switch channels, and the signal processing unit 34 on this core can simultaneously process composite signals transmitting different switch channels.

[0069] The ability to simultaneously process system feedback signals transmitting different switch channels of the LIDAR system is shown in FIG. 4B. This LIDAR system is typically configured to provide reliable LIDAR data when an object is within the operating distance range from the LIDAR system. This operating distance range can extend from a minimum operating distance to a maximum operating distance. The maximum round-trip time can be the time required for the system output signal to exit the LIDAR system, travel to an object with a surface at the maximum operating distance, and return to the LIDAR system. An example of the possible maximum round-trip time is τ M as denoted in FIG. 4B. When the object has a surface located at the maximum operating distance, the system feedback signal generated from that surface does not return to the LIDAR system until the maximum round-trip time has elapsed. For example, if the maximum round-trip time has a duration between two and three output periods as shown in FIG. 4B, the object has a surface positioned at the maximum operating distance during the output period p k and this LIDAR system is at the end of the output period p k+2 and at the end of the output period p k+3It does not generate a composite optical signal from its surface until between its start and the start of the output period. Thus, the duration of the two output periods elapses before LIDAR data of the surface positioned at the maximum operating distance can be generated. However, if an object has a surface disposed at a distance shorter than the maximum operating distance from the LIDAR system, LIDAR data can be generated earlier. For example, when the object is brought close enough to the LIDAR system, a composite optical signal from the object is generated early enough that LIDAR data is generated during the output period denoted as p k In some examples, the duration of the output period can be longer than 0.1, 0.2, or 0.3 of the maximum round-trip time and less than 0.5, 0.7, or 0.9 of the maximum round-trip time.

[0070] The upper part of FIG. 4B includes a plurality of horizontal rectangles each associated with a different one of the output periods. Each of these rectangles represents a data period and includes a plurality of different time zones. This rectangle is divided into a plurality of segments, each segment being denoted by a different time passing within the segment. For example, one of the segments in each data period is denoted as p k / τ M This segment indicates where the output period p k occurs with respect to the time scale on the x-axis. The notation of τ M also indicates that the maximum round-trip time (τ M ) starts at the start of this time segment. Another one of the segments in each data period is denoted as τ M and indicates that the maximum round-trip time (τ M ) during this time segment is continuously charged. The maximum round-trip time (τ M ) ends during this time segment.

[0071] Because there is a delay between the system output signal to be transmitted and the system feedback signal resulting from the result fed back to the LIDAR system, the composite signal does not include the contribution from the LIDAR signal until after the system feedback signal has been fed back to the LIDAR system. Since the composite signal requires the contribution from the system feedback signal due to the presence of the beat frequency, the electronic device uses the composite signal generated after the system feedback signal has been fed back to the LIDAR system to generate LIDAR data. In order for the electronic device to measure the beat frequency of the composite signal, the composite signal needs to exist for a certain period (measurement period, w). As a result, each of the data periods shown in Figure 4B includes a section denoted as w.

[0072] In Figure 4B, the measurement period (w) is located at the end of the data period to show the total duration of the data period when the object is positioned at the maximum operating distance. However, the actual position of the measurement period (w) in the data period can change in response to the object approaching the LIDAR system. For example, as the object moves towards the LIDAR system, the measurement period (w) can occur earlier in the data period.

[0073] In the example of Figure 4B, each of the data periods is associated with switch channel notations SC1 to SC4. As a result, the core shown in Figure 4B has N = 4 alternative waveguides. Therefore, the data period associated with the switch channel notation SC2 is the output period p during which the alternative waveguide 16 denoted as i = 2 in Figure 1 receives the emitted LIDAR signal from the signal guiding unit 14 k+1 including. However, since the signal guiding unit 14 is directing the emitted LIDAR signal towards the alternative waveguide 16 denoted as i = 3, the output period p k+1After the end of [operation], the emitted LIDAR signal is not received by the alternative waveguide 16 labeled i = 2. However, the LIDAR system continues to generate a composite signal transmitting the first switch channel for a significant period even after the imaging system stops outputting the system output signal transmitting the first switch channel i = 2. For example, the LIDAR system can continue to generate a composite signal transmitting the first switch channel for a period exceeding 0.1, 1, 1.3, or 1.5 times the output period after the imaging system stops outputting the system output signal transmitting the first switch channel. In some examples, the LIDAR system stops generating the composite signal transmitting the first switch channel for a period less than 2, 4, or 6 times the output period after the imaging system stops outputting the system output signal transmitting the first switch channel. As a result, the system can generate LIDAR data from the composite signal transmitting the first switch channel of the switch channels and at the same time direct the emitted LIDAR signal to another waveguide. Therefore, the system can generate LIDAR data from the beat frequency of the composite signal transmitting the first switch channel and at the same time output the system output signal transmitting the second switch channel. As shown in Figure 4B, in some examples, the system can generate LIDAR data from the beat frequency of the composite signal transmitting the first switch channel, and can also generate LIDAR data from the beat frequency of the composite signal transmitting the second switch channel, and at the same time output the system output signal transmitting the third switch channel. Therefore, the system can generate LIDAR data from the beat frequency of the composite signal transmitting the first switch channel, can also generate LIDAR data from the beat frequency of the composite signal transmitting the second switch channel, and can further generate LIDAR data from the beat frequency of the composite signal transmitting the third switch channel, and at the same time output the system output signal transmitting the fourth switch channel.As a result, in some examples, the system can simultaneously generate LIDAR data from the beat frequencies of two or more different composite signals, each transmitting a different one of the switch channels. The ability to generate LIDAR data for one switch channel while outputting a system output signal that transmits a different one of the switch channels reduces the period required for the imaging system to output a system output signal that transmits a specific channel.

[0074] In FIG. 4B, there are two different data periods associated with the switch channel notation SC1. The secondary generation occurs as a result of the electronic device sequentially guiding the emitted LIDAR signal to the alternative waveguides 16 denoted as i = 1 to i = N, and then returning to the alternative waveguide 16 denoted as i = 1 and repeating this sequence. The data period associated with the switch channel notation SCi does not start until the previous data period associated with the same switch channel (SC1) ends, in order to prevent the overlapping use of the signal processing units within the switch channel group 64 associated with switch channel i. For example, in FIG. 4B, the data periods denoted as SC1 do not overlap.

[0075] FIGS. 5A - 5B show an example of a suitable signal processing unit 34 for use as any of the signal processing units 34 in a LIDAR system constructed according to FIG. 1. The signal processing unit 34 includes an optoelectronic assembly configured to convert an optical signal into an electrical signal. FIG. 5A is a schematic diagram of an example of a suitable optoelectronic assembly including a first splitter 200 that splits the comparison signal received from the comparison waveguide 32 into a first comparison waveguide 204 and a second comparison waveguide 206. The first comparison waveguide 204 transmits a first portion of the comparison signal to the optical coupler 211. The second comparison waveguide 206 transmits a second portion of the comparison signal to the second optical coupler 212.

[0076] The processing unit of FIG. 5A also includes a second splitter 202 that splits the reference signal received from the reference waveguide 44 onto the first reference waveguide 210 and the second reference waveguide 208. The first reference waveguide 210 transmits the first portion of the reference signal to the optical coupler 211. The second reference waveguide 208 transmits the second portion of the reference signal to the second optical coupler 212.

[0077] The second optical coupler 212 combines the second portion of the comparison signal and the second portion of the reference signal into a second composite signal. Due to the frequency difference between the second portion of the comparison signal and the second portion of the reference signal, the second composite signal beats between the second portion of the comparison signal and the second portion of the reference signal.

[0078] The second optical coupler 212 also splits the resulting second composite signal onto the first auxiliary detector waveguide 214 and the second auxiliary detector waveguide 216. The first auxiliary detector waveguide 214 transmits the first portion of the second composite signal to a first auxiliary optical sensor 218 that converts the first portion of the second composite signal into a first auxiliary electrical signal. The second auxiliary detector waveguide 216 transmits the second portion of the second composite signal to a second auxiliary optical sensor 220 that converts the second portion of the second composite signal into a second auxiliary electrical signal. Examples of suitable optical sensors include germanium photodiodes (PDs) and avalanche photodiodes (APDs).

[0079] In some examples, the second optical coupler 212 splits the second composite signal, whereby the portion of the comparison signal included in the first portion of the second composite signal (i.e., the second portion of the comparison signal) is phase-shifted by 180° with respect to the portion of the comparison signal in the second portion of the second composite signal (i.e., the second portion of the comparison signal), while the portion of the reference signal in the second portion of the second composite signal (i.e., the second portion of the reference signal) is not phase-shifted with respect to the portion of the reference signal in the first portion of the second composite signal (i.e., the second portion of the reference signal). Alternatively, the second optical coupler 212 splits the second composite signal, whereby the portion of the reference signal in the first portion of the second composite signal (i.e., the second portion of the reference signal) is phase-shifted by 180° with respect to the portion of the reference signal in the second portion of the second composite signal (i.e., the second portion of the reference signal), while the portion of the comparison signal in the first portion of the second composite signal (i.e., the second portion of the comparison signal) is not phase-shifted with respect to the portion of the comparison signal in the second portion of the second composite signal (i.e., the second portion of the comparison signal). Examples of suitable optical sensors include germanium photodiodes (PDs) and avalanche photodiodes (APDs).

[0080] The first optical coupler 211 couples the first portion of the comparison signal and the first portion of the reference signal into a first composite signal. Due to the frequency difference between the first portion of the comparison signal and the first portion of the reference signal, the first composite signal beats between the first portion of the comparison signal and the first portion of the reference signal.

[0081] The optical coupler 211 also splits the first composite signal onto a first detector waveguide 221 and a second detector waveguide 222. The first detector waveguide 221 transmits the first portion of the first composite signal to a first optical sensor 223 that converts the first portion of the second composite signal into a first electrical signal. The second detector waveguide 222 transmits the second portion of the second composite signal to a second optical sensor 224 that converts the second portion of the second composite signal into a second electrical signal. Examples of suitable optical sensors include germanium photodiodes (PDs) and avalanche photodiodes (APDs).

[0082] In some examples, the optical coupler 211 divides the first composite signal, whereby the portion of the comparison signal included in the first portion of the composite signal (i.e., the first portion of the comparison signal) is phase-shifted by 180° with respect to the portion of the comparison signal in the second portion of the composite signal (i.e., the first portion of the comparison signal), while the portion of the reference signal in the first portion of the composite signal (i.e., the first portion of the reference signal) is not phase-shifted with respect to the portion of the reference signal in the second portion of the composite signal (i.e., the first portion of the reference signal). Alternatively, the optical coupler 211 divides the composite signal, whereby the portion of the reference signal in the first portion of the composite signal (i.e., the first portion of the reference signal) is phase-shifted by 180° with respect to the portion of the reference signal in the second portion of the composite signal (i.e., the first portion of the reference signal), while the portion of the comparison signal in the first portion of the composite signal (i.e., the first portion of the comparison signal) is not phase-shifted with respect to the portion of the comparison signal in the second portion of the composite signal (i.e., the first portion of the comparison signal).

[0083] When the second optical coupler 212 divides the second composite signal such that the portion of the comparison signal in the first portion of the second composite signal is phase-shifted by 180° with respect to the portion of the comparison signal in the second portion of the second composite signal, the optical coupler 211 also divides the composite signal such that the portion of the comparison signal in the first portion of the composite signal is phase-shifted by 180° with respect to the portion of the comparison signal in the second portion of the composite signal. When the second optical coupler 212 divides the second composite signal such that the portion of the reference signal in the first portion of the second composite signal is phase-shifted by 180° with respect to the portion of the reference signal in the second portion of the second composite signal, the optical coupler 211 also divides the composite signal such that the portion of the reference signal in the first portion of the composite signal is phase-shifted by 180° with respect to the portion of the reference signal in the second portion of the composite signal.

[0084] The first reference waveguide 210 and the second reference waveguide 208 are constructed to provide a phase shift between a first portion of the reference signal and a second portion of the reference signal. For example, the first reference waveguide 210 and the second reference waveguide 208 can be constructed to provide a 90° phase shift between a first portion of the reference signal and a second portion of the reference signal. As an example, one portion of the reference signal may be the in-phase component, and the other portion of the reference signal may be the quadrature component. Thus, one of the reference signal portions can be a sine function, and the other reference signal portion can be a cosine function. In one example, the first reference waveguide 210 and the second reference waveguide 208 are constructed such that the first reference signal portion is a cosine function and the second reference signal portion is a sine function. Accordingly, the portion of the reference signal in the second composite signal is phase-shifted with respect to the portion of the reference signal in the first composite signal, but the portion of the comparison signal in the first composite signal is not phase-shifted with respect to the portion of the comparison signal in the second composite signal.

[0085] The first optical sensor 223 and the second optical sensor 224 can be connected as a balanced detector, and the first auxiliary optical sensor 218 and the second auxiliary optical sensor 220 can also be connected as a balanced detector. For example, FIG. 5B shows a schematic diagram of the relationship between the electronic device, the first optical sensor 223, the second optical sensor 224, the first auxiliary optical sensor 218, and the second auxiliary optical sensor 220. The symbol of the photodiode is used to represent the first optical sensor 223, the second optical sensor 224, the first auxiliary optical sensor 218, and the second auxiliary optical sensor 220, but one or more of these sensors can have other configurations. In some examples, all of the components shown in the schematic diagram of FIG. 5B are included on the LIDAR chip. In some examples, the components shown in the schematic diagram of FIG. 5B are distributed between the LIDAR chip and an electronic device located away from the LIDAR chip.

[0086] The electronic device connects the first optical sensor 223 and the second optical sensor 224 as the first balanced detector 225, and also connects the first auxiliary optical sensor 218 and the second auxiliary optical sensor 220 as the second balanced detector 226. Specifically, the first optical sensor 223 and the second optical sensor 224 are connected in series. Also, the first auxiliary optical sensor 218 and the second auxiliary optical sensor 220 are connected in series. The series connection in the first balanced detector communicates with the first data line 228 that transmits the output from the first balanced detector as the first data signal. The series connection in the second balanced detector communicates with the second data line 232 that transmits the output from the second balanced detector as the second data signal. The first data signal is the electrical representation of the first composite signal, and the second data signal is the selected representation of the second composite signal. Therefore, the first data signal includes contributions from the first waveform and the second waveform, and the second data signal is a composite of the first waveform and the second waveform. The portion of the first waveform in the first data signal is phase-shifted with respect to the portion of the first waveform in the first data signal, while the portion of the second waveform in the first data signal is in phase with the portion of the second waveform in the first data signal. For example, the second data signal includes a portion of the reference signal that is phase-shifted with respect to different portions of the reference signal included in the first data signal. Also, the second data signal includes a portion of the comparison signal that is in phase with different portions of the comparison signal included in the first data signal. The first data signal and the second data signal are beating as a result of the beat between the comparison signal and the reference signal, that is, the beat in the first composite signal and the second composite signal.

[0087] The electronic device 62 includes a conversion mechanism 238 configured to perform a mathematical transformation on the first data signal and the second data signal. For example, the mathematical transformation can be a complex Fourier transform that takes the first data signal and the second data signal as inputs. Since the first data signal is the in-phase component and the second data signal is the quadrature component, the first data signal and the second data signal function together as a complex data signal, where the first data signal is the real component of the input and the second data signal is the imaginary component of the input.

[0088] The conversion mechanism 238 includes a first analog-to-digital converter (ADC) 264 that receives a first data signal from the first data line 228. The first analog-to-digital converter (ADC) 264 converts the first data signal from analog form to digital form and outputs a first digital data signal. The conversion mechanism 238 includes a second analog-to-digital converter (ADC) 266 that receives a second data signal from the second data line 232. The second analog-to-digital converter (ADC) 266 converts the second data signal from analog form to digital form and outputs a second digital data signal. The first digital data signal is a digital representation of the first data signal, and the second digital data signal is a digital representation of the second data signal. Accordingly, the first digital data signal and the second digital data signal together function as a composite signal, where the first digital data signal functions as the real component of the composite signal and the second digital data signal functions as the imaginary component of the composite data signal.

[0089] The conversion mechanism 238 includes a conversion unit 268 that receives a composite data signal. For example, the conversion unit 268 receives the first digital data signal as an input from the first analog-to-digital converter (ADC) 264, and also receives the second digital data signal as an input from the second analog-to-digital converter (ADC) 266. The conversion unit 268 can be configured to perform a mathematical conversion on the composite signal and convert it from the time domain to the frequency domain. The mathematical conversion can be a composite conversion such as a composite fast Fourier transform (FFT). By a composite conversion such as a composite fast Fourier transform (FFT), the frequency of the comparison signal is clearly shifted relative to the system output signal.

[0090] The conversion mechanism 238 includes a peak finder 270 that receives the output from the mathematical converter 268. The peak finder 270 detects the peak of the output of the mathematical converter 268 and identifies one or more peaks of the beat frequency of the composite optical signal.

[0091] The electronic device is configured to generate LIDAR data by combining the outputs from different signal processing units 34. For example, the electronic device can generate LIDAR data by combining the beat frequencies from different signal processing units 34. Specifically, the electronic device can combine the beat frequencies of a plurality of wavelength channels associated with the same switch channel to generate LIDAR data during the output period. For example, FIG. 5C shows a part of the electronic device including the mathematical converters 268 from different signal processing units.

[0092] The mathematical converters 268 are shown to be arranged in different switch channel groups 64. As a result, the mathematical converters 268 within the same switch channel group are each associated with a different wavelength channel, but the switch channels are the same. Therefore, each of the mathematical converters 268 is represented by a wavelength channel index (λ j ) and a switch channel index (j).

[0093] The electronic device includes a plurality of LIDAR data generators 272. Each of the LIDAR data generators 272 receives the beat frequency from the peak finder 270 within the same switch channel group 64. For example, in the electronic device, one of the LIDAR data generators 272 receives the beat frequency associated with different wavelength channels (λ1 to λ M ) and also associated with channel i = l, while the other one of the LIDAR data generators 272 is configured to receive the beat frequency associated with different wavelength channels (λ1 to λ M ) and also associated with channel i = 2. As a result, each of the LIDAR data generators 272 can be associated with a different one of the switch channels.

[0094] Each of the LIDAR data generators 272 combines beat frequencies from different wavelength channels resulting from the same output period to generate LIDAR data for that output period. For example, the following equation applies to a wavelength channel in which the frequency of the system output signal that transmits that channel during the output period, such as the LIDAR output signal λ1 in FIG. 5B during output period c1, increases: +f ub = -f d + ατ0. Here, f ub is the beat frequency output by one of the peak finders for the channel during the output period, f d is the Doppler shift: f d = 2νf c / c), where f c is the frequency of the LIDAR output signal at the start of the output period, ν is the radial velocity between the reflecting object and the LIDAR chip when the direction from the reflecting object towards the chip is assumed to be the positive direction, c is the speed of light, α represents the rate at which the frequency of the emitted LIDAR signal increases or decreases during the output period, and τ0 is the round-trip delay of a stationary reflecting object (the time between the system output signal emitted from the LIDAR system and the system feedback signal returned to the LIDAR system). The following equation applies to a channel in which the frequency of the system output signal that transmits that channel during the output period, such as the LIDAR output signal λ2 in FIG. 5B during output period c1, decreases: -f db = -f d - ατ0. Here, f db is the beat frequency output by one of the peak finders for the channel during the output period. In these two equations, f d and τ0 are unknowns. These two equations are solved for these two unknowns f d and τ0. The value of f db is generated from LIDAR output signals that transmit different wavelength channels from the LIDAR output signal for which the value of f ub is generated. Therefore, f db and f ubThe value is derived from different signal processing units 34. Different wavelength channels are incident on the same sample area simultaneously. Then, the radial velocity during the output period can be measured from the Doppler shift (ν = c*f d / (2f c )) and the separation distance of the sample area can be measured from c*τ0 / 2. As a result, the LIDAR data for a single output period can be measured using the wavelength channels received by different signal processing units.

[0095] As described above, the LIDAR system can be configured to operate at the maximum operating distance. When generating LIDAR data, the electronic device can remove the beat frequency output from the peak finder having a frequency exceeding the threshold related to the maximum operating distance. For example, the electronic device can ignore the beat frequency output from the peak finder having a frequency exceeding the threshold.

[0096] As described above, the LIDAR system can output a system output signal that transmits two or more wavelength channels. For example, the LIDAR system can transmit three channels having a frequency-versus-time waveform according to FIGS. 4A and 4B. This may be desirable in situations where during the output period, the composite optical signal transmits light reflected by a plurality of different objects. Different reflecting objects within the sample area may not be physically distinct objects, but different surfaces of the same object at different distances from the LIDAR system, and / or objects moving at different radial velocities relative to the LIDAR system, such as those that can occur on a jagged object rotating and translating relative to the LIDAR system.

[0097] In a situation where a composite optical signal transmits light reflected by a plurality of different objects during an output period, the mathematical converter 268 can output values of two or more frequencies, where each of the different frequency values is associated with a different one of the reflecting objects. In these examples, it may be necessary to match the beat frequencies provided by the peak finders 270 within different signal processing units. Match the frequencies so that the frequencies to be matched are the frequencies from the same reflecting object. Additional channels such as λ3 can be used to match the frequencies. LIDAR data is generated for each pair of the matched frequencies and considered and / or processed as LIDAR data for different reflecting objects.

[0098] An example of a LIDAR system includes a light source configured to generate a system output signal that transmits three wavelength channels. One of the system output signals transmits a wavelength channel having a frequency versus time according to channel λ1 of FIG. 4A, another LIDAR output signal transmits a channel having a frequency versus time according to channel λ2 of FIG. 4A, and another LIDAR output signal transmits a channel having a frequency versus time according to channel λ3 of FIG. 4A. In this case, the beat frequency output from the peak finder associated with the signal processing unit that receives channel λ3 is f3 = -f d + α” τ0, where f d represents the Doppler shift, α” represents the rate at which the frequency of the LIDAR output signal λ3 increases or decreases during the output period, and τ0 is the round-trip delay. When the frequency versus time of λ3 follows FIG. 4B, α” = 0 and the equation is f3 = -f dIt decreases to. Using the equation of f3, the theoretical values of f3 for at least some possible frequency pairs can be generated, and these theoretical values of f3 can be compared with the measured values of f3 provided by the peak finder associated with the signal processing unit that receives channel λ3. The frequency pair that provides the theoretical value of f3 closest to the measured value of f3 is regarded as the matching pair. LIDAR data can be generated for each matching pair, and the LIDAR data from the matching pairs can be considered and / or processed as the LIDAR data of each different reflective object within the sample area.

[0099] As an example of identifying a matching pair, the mathematical converter 168 associated with the signal processing unit 34 that receives the wavelength channel λ1 outputs two different frequencies for f db :f d11 and f d12 The peak finder associated with the signal processing unit that receives channel λ2 outputs two different frequencies for f db :f d21 and f d22 In this example, the possible frequency pairings are (f d11 , f d21 ); (f d11 , f d22 ); (f d12 , f d21 ); and (f d12 , f d22 ). The values of f d and τ0 can be calculated for each of the four possible frequency pairings as described above. Each pair of values of f d and τ0 can be substituted into f3 = -f d + α” τ0 to generate the theoretical values of f3 for each possible frequency pairing. As described above, when α” = 0, the equation is f2 = -f dIt decreases to these. In these examples, it is not necessary to calculate τ0 for possible frequency pairings. The mathematical converter 168 associated with the signal processing unit that receives channel λ3 also outputs two values of f3, each of which is treated as a measured value of f3. A frequency pair having a theoretical value of f3 closest to each measured value of f3 is considered a matching pair. As described above, LIDAR data can be generated for each matching pair and can also be considered and / or processed as different LIDAR data of the reflective objects within the sample area.

[0100] The mathematical converter 268 is disclosed as performing a composite conversion on a complex signal, but this composite conversion can be replaced with an actual conversion performed on an actual signal. As a result, the optoelectronic assembly of FIG. 5A can be simplified, thereby excluding the second optical coupling section 212, the comparison waveguide 206, the second splitter 202, and the second reference waveguide 208.

[0101] FIG. 6A is a schematic diagram of the relationship between a LIDAR system including a single LIDAR core (not shown) and a field of view. The field of view is represented by a dashed line extending from the LIDAR system to a virtual surface within the field of view. To indicate the range of the field of view, this virtual surface is arranged at the maximum operating distance (d M denoted as) from the LIDAR system.

[0102] As described above, the LIDAR system can include one or more beam guiding units (not shown in FIGS. 6A to 6C) that steer the system output signal to different sample areas 300 within the field of view. A part of the sample area is shown as a rectangle on the plane of FIG. 6A. The electronic device generates LIDAR data in a series of cycles by sequentially irradiating different sample areas within the field of view of the LIDAR system. LIDAR data can be generated for each sample area.

[0103] In FIG. 6A, since the system output signal can continue to be scanned during the output period associated with the sample region, only a part of the illustrated sample region is shown to be irradiated by the system output signal. For example, the system output signal in FIG. 6A can be scanned in the direction of the arrow marked A during the output period. By this scan, the system output signal can irradiate the entire length of the plane marked ct during the output period.

[0104] FIG. 6B is a side view of a virtual plane from FIG. 6A. The LIDAR system can include a plurality of steering mechanisms (not shown in FIGS. 6A - 6C) that steer the system output signal to different sample regions within the field of view. The dashed line in FIG. 6B represents the path along which the center of gravity of the system output signal transmitting through switch channel SC2 travels across the plane within the field of view in response to the steering of the system output signal by only one or more beam guiding portions 78 disclosed in the context of FIG. 3. The sample region 300 is represented by a rectangle arranged along the path of the system output signal.

[0105] The scan path of the system output signal shown in FIG. 6B has a high - speed axis indicated by the arrow marked "high speed" in FIG. 6B. The scan path of the system output signal shown in FIG. 6B has a low - speed axis indicated by the arrow marked "low speed" in FIG. 6B. The scan speed of the system output signal in the direction of the high - speed axis is faster than the scan speed of the system output signal in the direction of the low - speed axis.

[0106] To obtain LIDAR data results representing the entire field of view, generally, it is desirable that the number of sample regions in the direction of the fast axis matches the number of sample regions in the direction of the slow axis. The scan speed in the fast direction can be increased such that the number of zigzags through which the system output signal progresses across the field of view increases. The increase in the number of zigzags increases the number of sample regions in the direction of the fast axis. However, as the applications of the LIDAR system increase, the size required for the field of view and the maximum operating distance makes the scan speed required for one or more beam guiding units 78 infeasible or not practical and / or requires a power that is undesirably high.

[0107] Figure 6C is a side view of a virtual plane from Figure 6A. The dashed line in Figure 6C represents the path along which the center of gravity of the system output signal moves when the system output signal transmitting through switch channel SC2 is steered only by one or more beam guiding units 78 (beam guiding units) disclosed in the context of Figure 3. The sample regions in Figure 6C are vertically separated from each other and from the path provided by the beam guiding unit as indicated by the dashed line. This vertical separation results from the electronics that operates signal guiding unit 14 to change the direction in which the system output signal progresses away from the LIDAR system. As a result, due to the operation of signal guiding unit 14, the system output signal is moved in a direction transverse to the path provided by the beam guiding unit. For example, the sample region 129 denoted as SR i can represent the sample region when signal guiding unit 14 is operated such that the system output signal transmits through channel C i . As is apparent from the order of the sample regions shown in Figure 6C, signal guiding unit 14 is operated such that the system output signal transmits sequentially through switch channel C i in the order from i = 1 to N, and this order is repeated. Although Figure 6C shows the order of the switch channels in the forward direction, this channel order can be repeated in the reverse order. As a result, the forward order (i = 1 to N) can alternate with the reverse order (i = N to 1).

[0108] The scan speed on the fast axis can be reduced relative to the scan speed of the fast axis in FIG. 6B while maintaining the same frame rate (the rate at which each sample region within the field of view is illuminated by the system output signal). For example, the scan speed of the fast axis in FIG. 6C is approximately 1 / N times the scan speed of the fast axis in FIG. 6B, where N is the number of alternative waveguides 16. The reduced scan speed of the fast axis is evident from the reduced number of zigzags within the same frame scan time (1 / frame rate). As a result of the reduced scan speed of the fast axis, the length of the sample region is shortened in the direction of the fast axis, thereby reducing the size. As the size of the sample region becomes smaller, the reliability of the LIDAR data improves.

[0109] In FIG. 6B, the distance that the system output signal travels along the fast axis during the duration of each switch sequence is denoted as ct. In FIG. 6C, this same distance is also denoted as ct. Of each distance denoted as ct in FIGS. 6B and 6C, there are 12 sample regions that extend across the slow axis. As a result, by combining using the signal guiding unit 14 to manipulate the system output signal and reducing the scan speed of the fast axis, the same resolution of the slow axis can be achieved as when the scan speed of the fast axis is increased.

[0110] The scan speed of the fast axis (the speed provided by the beam guiding unit in the direction of the fast axis) can be represented by the angular change speed in the direction of the fast axis (the angular change speed of the fast axis) at which the system output signal travels away from the LIDAR system. The scan speed of the slow axis (the speed provided by the beam guiding unit in the direction of the slow axis) can be represented by the angular change speed along the slow axis (the angular change speed of the slow axis) at which the system output signal travels away from the LIDAR system. The slow axis and the fast axis may be perpendicular to each other. In some examples, the ratio of the angular change speed of the fast axis to the angular change speed of the slow axis is greater than 1:1, 2:1, 3:1, or 4:1, and / or less than 5:1, 10:1, or 100:1. Additionally or alternatively, the angular change speed of the fast axis can be faster than 100 degrees / second, 200 degrees / second, or 300 degrees / second, and / or less than 500 degrees / second, 1000 degrees / second, or 2000 degrees / second, and / or the angular change speed of the slow axis can be faster than 20 degrees / second, 50 degrees / second, or 100 degrees / second, and / or less than 200 degrees / second, 500 degrees / second, or 1000 degrees / second.

[0111] Figures 6B and 6C show one or more beam guiding units 78 maneuvering the system output signal back and forth along a zigzag path across the field of view, although one or more beam guiding units 78 can use other patterns to maneuver the system output signal back and forth across the field of view. For example, this path need not include straight line segments connected at sharp angles and can instead include straight line segments connected by curves. Alternatively, this path can include curves and / or segments of curves and can exclude straight line segments. For example, this path can be configured as a series of S-shaped segments.

[0112] Figures 6A - 6C show the field of view of a LIDAR system having a single core. When the LIDAR system has multiple cores, the fields of view of different cores can be joined together to form the field of view of the LIDAR system.

[0113] Suitable platforms for LIDAR chips include, but are not limited to, silica, indium phosphide, and silicon-on-insulator wafers. FIG. 7 is a cross-sectional view of a silicon-on-insulator wafer. A silicon-on-insulator (SOI) wafer includes a buried layer 300 between a substrate 302 and an optically transmissive medium 304. In a silicon-on-insulator wafer, the buried layer 300 is silica, while the substrate 302 and the optically transmissive medium 304 are silicon. The substrate of an optical platform such as an SOI wafer can function as the base of a LIDAR chip. For example, in some instances, the optical components shown in FIG. 1 can be disposed on the same substrate on or over and / or on the sides of the substrate.

[0114] The portion of the LIDAR chip shown in FIG. 7 includes a waveguide structure suitable for use with a chip constructed from a silicon-on-insulator wafer. A ridge 306 of the optically transmissive medium 304 extends away from a slab region 308 of the optically transmissive medium 304. An optical signal is confined between the top of the ridge and the buried layer 300. As a result, the ridge 306 at least partially defines the waveguide.

[0115] The dimensions of the ridge waveguide are shown in FIG. 7. For example, the ridge has a width denoted as w and a height denoted as h. The thickness of the slab region is denoted as t. In LIDAR applications, these dimensions may be more important than those used in other applications because they need to use a higher level of optical power. The ridge width (denoted as w) is greater than 1 μm and less than 4 μm, the ridge height (denoted as h) is greater than 1 μm and less than 4 μm, and the thickness of the slab region is greater than 0.5 μm and less than 3 μm. These dimensions can be applied to the straight or substantially straight portions of the waveguide, the curved portions of the waveguide, and the tapered portions of the waveguide. Thus, these portions of the waveguide are single mode. However, in some examples, these dimensions are applied to the straight or substantially straight portions of the waveguide. Additionally or alternatively, to reduce optical loss in the curved portions of the waveguide, the curved portions of the waveguide can have a reduced slab thickness. For example, the curved portion of the waveguide can have a ridge extending away from a slab region with a thickness of 0.0 μm or more and less than 0.5 μm. The above dimensions generally provide a straight or substantially straight portion of the waveguide having a single-mode structure, but they can result in multimode tapered and / or curved portions. The coupling between the multimode geometry and the single-mode geometry can be performed using a taper that does not substantially excite higher-order modes. Thus, the waveguide can be configured such that the signal transmitted within the waveguide is transmitted in single mode even when it is transmitted in a waveguide section having multimode dimensions. The waveguide structure of FIG. 7 is suitable for all or part of the waveguide on the LIDAR chip constructed according to FIG. 1.

[0116] Suitable signal guiding units 14 for use with LIDAR chips include, but are not limited to, optical switches such as cascaded Mach-Zehnder interferometers and micro-ring resonator switches. In one example, the signal guiding unit 14 includes a cascaded Mach-Zehnder interferometer that uses a thermal phase shifter or a phase shifter of free carrier injection. FIGS. 8A and 8B show an example of an optical switch including a cascaded Mach-Zehnder interferometer 416. FIG. 8A is a top view of the optical switch. FIG. 8B is a cross-sectional view of the optical switch shown in FIG. 8A taken along the line indicated as B in FIG. 8A.

[0117] The optical switch receives the outgoing LIDAR signal from the utility waveguide 12. The optical switch is configured to direct the outgoing LIDAR signal to one of a plurality of alternative waveguides 16. The optical switch includes an interconnect waveguide 414 that connects a plurality of Mach-Zehnder interferometers 416 in a cascaded arrangement. Each Mach-Zehnder interferometer 416 directs the outgoing LIDAR signal to one of two interconnect waveguides 414. The electronics can operate each Mach-Zehnder to select which of the two interconnect waveguides 414 receives the outgoing LIDAR signal from the Mach-Zehnder interferometer 416. The interconnect waveguide 414 that receives the outgoing LIDAR signal can be selected such that the outgoing LIDAR signal is directed through the optical switch to a particular one of the alternative waveguides 16.

[0118] Each Mach-Zehnder interferometer 416 includes two branched waveguides 418, each of which receives a portion of the output LIDAR signal from the utility waveguide 12 or from the interconnect waveguide 414. Each Mach-Zehnder interferometer 416 includes a guiding section 420 that receives two portions of the output LIDAR signal from the branched waveguides 418. The guiding section 420 steers the output LIDAR signal to one of two interconnect waveguides 414 configured to receive the output LIDAR signal from the guiding section 420. The interconnect waveguide 414 to which the output LIDAR signal is guided is a function of the phase difference between two different portions of the output LIDAR signal received by the guiding section 420. FIG. 8A shows a directional coupler operating as the guiding section 420, although other guiding sections 420 can be used. Suitable alternatives to the guiding section 420 include, but are not limited to, multimode interference (MMI) devices and tapered couplers.

[0119] Each Mach-Zehnder interferometer 416 includes a phase shifter 422 disposed along one of the branched waveguides 418. The output section includes a conductor 424 in electrical communication with the phase shifter 422. Since the conductor 424 is shown in dashed lines, it can be easily distinguished from the components below it. The conductor 424 is terminated at contact pads 426, respectively. The contact pads 426 can be used to provide electrical communication between the conductor 424 and the electronics. Thus, the conductor 424 provides electrical communication between the electronics and the phase shifter 422, enabling the electronics to operate the phase shifter 422. Suitable conductors 424 include, but are not limited to, metal traces. Suitable materials for the conductor include, but are not limited to, titanium, aluminum, and gold.

[0120] The electronic device can operate each phase shifter 422 so as to control the phase difference between portions of the emitted LIDAR signal received by the guiding portion 420. In one example, the phase shifter 422 can be operated to change the refractive index of at least a portion of the branching waveguide 418. By changing the refractive index of a portion of the branching waveguide 418 within the Mach-Zehnder interferometer 416, the effective length of the branching waveguide 418 is changed, and thus the phase difference between portions of the emitted LIDAR signal received by the guiding portion 420 is changed. With the function of the electronic device to change the phase difference, the electronic device can select the interconnecting waveguide 414 that receives the emitted LIDAR signal from the guiding portion 420.

[0121] FIG. 8B shows an example of a suitable configuration of the phase shifter 422 on the branching waveguide 418. The branching waveguide 418 is at least partially defined by a ridge 306 of the optical transmission medium 304 that extends away from the slab region 98 of the optical transmission medium 304. The doped region 428 extends into the slab region 308, one of the doped regions contains an n-type dopant, and one of the doped regions 428 contains a p-type dopant. The first cladding 430 is disposed between the optical transmission medium 304 and the conductor 424. The conductors 424 each extend through an opening in the first cladding 430 to contact one of the doped regions 428. The second cladding 432 is optionally disposed on the first cladding 430 and on the conductor 424. To generate a current through the branching waveguide 418, the electronic device can apply a forward bias to the conductor 424. As a result, by injecting carriers into the branching waveguide 418, absorption of free carriers that change the refractive index within the branching waveguide 418 is caused.

[0122] The first cladding 430 and / or the second cladding 432 shown in FIG. 8B can each represent one or a plurality of layers of material. The material of the first cladding 430 and / or the second cladding 432 can be selected to achieve electrical insulation of the conductor 424, a reduction in refractive index with respect to the optical transmission medium 304, stress reduction, and mechanical and environmental protection. Suitable materials for the first cladding 430 and / or the second cladding 432 include, but are not limited to, silicon nitride, tetraorthosilicate (TEOS), silicon dioxide, silicon nitride, and aluminum oxide. One or more materials of the first cladding 430 and / or the second cladding 432 may or may not be added.

[0123] When the LIDAR system includes a plurality of cores, the LIDAR system can include a plurality of signal guiding portions 76, and different signal guiding portions 76 can receive LIDAR output signals from different selections of cores. As an example, FIG. 9 shows the LIDAR system of FIG. 3 modified to have a plurality of signal guiding portions 76 each receiving a LIDAR output signal from one of different cores.

[0124] FIG. 1 shows each of the cores including different light sources 10. However, a plurality of cores, all of the cores, or a part of the cores can receive the emitted LIDAR signal from a common light source. In some examples, the cores are arranged in groups, and each core within a group receives the emitted LIDAR signal from the same common light source, and the cores in different groups receive the emitted LIDAR signal from different common light sources. In some examples, a group of cores can include one of the cores. As an example, FIG. 10 shows the LIDAR system of FIG. 3, where the light source 10 is located outside the cores, and each of these cores receives the emitted LIDAR signal from the light source. The light source 10 can be configured as disclosed in the context of FIG. 2.

[0125] The first optical link 440 provides optical communication between the light source 10 and the signal splitter 442. The second optical link 444 provides optical communication between the signal splitter 442 and the utility waveguide 12 on a different core 4. The light source 10 outputs a preliminary signal that is received on the first optical link 440. The signal splitter 442 receives the preliminary signal from the first optical link 440. The signal splitter 442 splits the preliminary signal into split signals that are respectively received on different ones of the second optical links 444. Each of the utility waveguides 12 receives a split signal from a different one of the optical links 444. The portion of the split signal that is incident on the utility waveguide functions as an outgoing LIDAR signal.

[0126] The LIDAR system can optionally include an amplifier 446 disposed along the first optical link 440 to amplify the power of the preliminary signal. Amplifiers 446 suitable for use along an optical link include, but are not limited to, SOAs, erbium-doped fiber amplifiers (EDFAs), and praseodymium-doped fiber amplifiers (PDFAs).

[0127] When it is desirable for different outgoing LIDAR signals to have the same or substantially the same wavelength distribution, a suitable signal splitter 442 includes, but is not limited to, a wavelength-independent signal combiner, such as an optical coupler, a y-junction, an MMI, a cascaded evanescent optical coupler, and a cascaded-connected y-junction. When it is desirable for different outgoing LIDAR signals to have different wavelength distributions, a suitable signal splitter 442 includes, but is not limited to, a wavelength-dependent signal splitter 442, such as an arrayed waveguide grating (AWG) and an optical demultiplexer such as an echelle grating.

[0128] In some examples where multiple different cores receive an outgoing LIDAR signal from a common light source, only one of the cores that receives its outgoing LIDAR signal from this common light source includes a control branch. As a result, other cores that receive an outgoing LIDAR signal from the same common light source can exclude the directional coupler 66, the control waveguide 68, and the controller 70 shown in FIG. 1.

[0129] As is apparent from FIG. 1, the LIDAR system can optionally include one or more optical signal amplifiers 446. For example, the amplifier 446 can optionally be arranged along the utility waveguide as shown in the LIDAR system of FIG. 1. In another example, the amplifier 446 can optionally be arranged along all or part of the alternative waveguide 16 as shown in the LIDAR system of FIG. 1B. The electronics can operate the amplifier 446 to amplify the emitted LIDAR signal and thus the power of the system output signal. The electronics can operate each of the amplifiers 446 to amplify the power of the emitted LIDAR signal. Suitable amplifiers 446 for use on the LIDAR chip include, but are not limited to, semiconductor optical amplifiers (SOAs).

[0130] The amplifiers 446 shown in FIG. 1 are each arranged in front of one of the splitters 24. In some examples, this arrangement of the amplifier 446 can cause one or more components selected from the group consisting of the first auxiliary optical sensor 218, the second auxiliary optical sensor 220, the first optical sensor 223, and the second optical sensor 224 to saturate. For example, the amplifier 446 can increase the power level of the reference signal to a level at which saturation occurs. A beam dump can be used to reduce the power level of the reference signal to a level at which saturation is reduced or eliminated.

[0131] As is apparent from FIG. 5B, the LIDAR system can optionally include one or more electrical signal amplifiers 447. Any of the amplifiers 447 is arranged to provide amplification of a first data signal traveling between a first optical sensor such as the first balanced detector 225 and an analog-to-digital converter, or a second data signal traveling between a second optical sensor such as the second balanced detector 226 and an analog-to-digital converter. FIG. 3D shows each of the electrical signal amplifiers 447 arranged along the first data line 228 or the second data line 232, but the electrical signal amplifier 447 can be arranged along the common data line 273 or the second common data line 275. FIG. 3E shows each of the electrical signal amplifiers 447 arranged along the common data line 273 or the second common data line 275, but the electrical signal amplifier 447 can be arranged along the first data line 228 or the second data line 232. Suitable electrical signal amplifiers 447 include, but are not limited to, transimpedance amplifiers (TIAs).

[0132] FIG. 11 shows a portion of a LIDAR chip including a beam dump 72 configured to scatter a combined portion of the outgoing LIDAR signal and not reflect a substantial amount of the combined portion of the outgoing LIDAR signal into the alternative waveguide 16. For example, the beam dump 72 can be a recess 454 etched into the optical transmission medium 304 of the silicon-on-insulator wafer to a depth at which a dump signal is incident on one or more sides of the recess 454. The recess 454 can be shaped to cause scattering of the dump signal. For example, the recess 454 can have a star shape or can include any number of irregularly arranged sides. In some examples, the recess 454 can extend through the optical transmission medium to a lower layer such as a buried layer of the silicon-on-insulator wafer.

[0133] The optical sensor that interferes with the waveguide on the LIDAR chip can be a component separated from the chip and attached to the chip. For example, the optical sensor can be a photodiode or an avalanche photodiode. Examples of suitable optical sensor components include, but are not limited to, InGaAs PIN photodiodes or InGaAs APDs (avalanche photodiodes) manufactured by Hamamatsu in Hamamatsu, Japan. These optical sensors can be centrally arranged on the LIDAR chip. Alternatively, all or part of the waveguide terminated by the optical sensor can be terminated with a facet at the edge of the chip, and the optical sensor can be attached to the edge of the chip on the facet so that the optical sensor receives the light passing through the facet. The use of an optical sensor as a separate component is suitable for all or part of the optical sensor selected from the group consisting of the first optical sensor and the second optical sensor.

[0134] As an alternative to a separate-component optical sensor, all or part of the optical sensor can be integrated with the chip. For example, examples of optical sensors that interfere with ridge waveguides on chips constructed from silicon-on-insulator wafers can be found in Optics Express Vol.15, No.21, 13965-13971 (2007); U.S. Patent No. 8,093,080 issued on January 10, 2012; U.S. Patent No. 8,242,432 issued on August 14, 2012; and U.S. Patent No. 6,108,8472 issued on August 22, 2000, all of which are incorporated herein by reference in their entirety. The use of an optical sensor integrated with the chip is suitable for all or part of the optical sensor selected from the group consisting of the first optical sensor and the second optical sensor.

[0135] The electronic device 62 applied to the LIDAR system includes, but is not limited to, an analog electrical circuit, a digital electrical circuit, a processing unit, a microprocessing unit, a digital signal processing unit (DSP), an application-specific integrated circuit (ASIC), a computer, a microcomputer, or a controller including or composed of a combination suitable for performing the above-described operations, monitoring, and control functions. In some examples, the controller has access to a memory including instructions executed by the controller during the execution of the operations, control, and monitoring functions. Although the electronic device is shown as a single part in a single location, these can include a plurality of different parts that are independent of each other and / or are arranged in different locations. Also, as described above, all or part of the disclosed electronic device may be included on a chip including an electronic device integrated with the chip.

[0136] The components on the LIDAR chip can be fully or partially integrated with the LIDAR chip. For example, an integrated optical component can include or consist of a part of the wafer from which the LIDAR chip is manufactured. A wafer that can function as a platform for the LIDAR chip can include multiple material layers. At least a part of different layers can be of different materials. As an example, a silicon-on-insulator wafer including an embedded layer 300 between a substrate 302 and an optical transmission medium 304 is shown in FIG. 4. Integrated on-chip components can be formed by using etching and masking techniques to define the features of the components in the optical transmission medium 304. For example, a slab 318 that defines a waveguide and a stop recess can be formed in a desired region of the wafer using different etchings of the wafer. As a result, the LIDAR chip can include a part of the wafer, and the integrated on-chip components can each include or consist of a part of the wafer. Further, the integrated on-chip components can be configured such that an optical signal traveling through the component travels through one or more of the layers originally included in the wafer. For example, the waveguide in FIG. 4 guides an optical signal from the wafer through the optical transmission medium 304. The integrated components can optionally include other materials of the materials present on the wafer. For example, the integrated components can include a reflective material and / or a cladding.

[0137] Numerical notations such as first, second, third, etc. are used to distinguish different features and components and do not indicate the order or presence of features denoted by smaller numerical values. For example, a second component can be present without a first component being present, and / or a third step can be performed before a first step. Each of the optical signals disclosed above includes, consists of, or is essentially composed of light from the optical signals before the optical signals are derived. For example, an incident LIDAR signal includes, consists of, or is essentially composed of light from the LIDAR input signal.

[0138] LIDAR systems are disclosed as using composite signals such as composite data signals, but LIDAR systems can also use actual signals. As a result, the mathematical transformation can be an actual transformation, and components related to the generation and use of orthogonal components can be removed from the LIDAR system. As a result, the LIDAR system can use a single signal combiner. Additionally or alternatively, a single optical sensor can replace each of the balanced detectors.

[0139] Those skilled in the art will readily conceive of other embodiments, combinations, and modifications of the invention in view of the present teachings. Accordingly, the invention should be limited only by the following claims, which, when viewed in conjunction with the above specification and the accompanying drawings, include all such embodiments and modifications.

Claims

1. An imaging system, A LIDAR system including a signal guiding unit capable of guiding an emitted LIDAR signal to any one of a plurality of different alternative waveguides, Each of the alternative waveguides is characterized in that an optical signal including light from the emitted LIDAR signal guided to that particular one is transmitted through a switch channel associated with that alternative waveguide, and is associated with different switch channels; The LIDAR system is configured to output a system output signal including light from the emitted LIDAR signal, The system output signal is transmitted through different switch channels; The LIDAR system is configured to receive a system feedback signal including light from one of the system output signals after an object outside the system receives and reflects the system output signal; The LIDAR system includes a signal combining unit that combines light from the system feedback signal transmitted through different switch channels with a reference signal to generate different composite signals, A LIDAR system, and An electronic device that calculates LIDAR data from one or more frequencies of the composite signals, the LIDAR data indicating the radial velocity and / or distance between the LIDAR system and one or more objects outside the LIDAR system; The LIDAR system is configured to continue generating a composite signal transmitted through the first switch channel for a certain period even after the imaging system stops outputting the system output signal transmitted through the first one of the switch channels, An electronic device Comprising an imaging system.

2. The imaging system according to claim 1, wherein the LIDAR system can guide the emitted LIDAR signal to a different one of the alternative waveguides while still generating the LIDAR data from the frequency of the composite signal transmitted through the first switch channel.

3. The imaging system according to claim 1, wherein the emitted LIDAR signal is transmitted through a plurality of different wavelength channels.

4. The imaging system according to claim 1, wherein the system output signal is transmitted through a plurality of different wavelength channels.

5. The imaging system according to claim 4, wherein at least two of the wavelength channels have frequencies chirped at different speeds and / or in different directions.

6. The imaging system according to claim 4, wherein the frequencies of the different wavelength channels do not overlap.

7. The imaging system according to claim 4, wherein each of the wavelength channels in the system output signal is incident on the same sample region in the field of view simultaneously.

8. The signal combining section is one of a plurality of signal combining sections included in the LIDAR system, each of the signal combining sections generates a composite signal, and the composite signals generated by different signal combining sections transmit different ones of the wavelength channels. The imaging system according to claim 1.

9. The imaging system according to claim 8, wherein the electronic device calculates the LIDAR data of the sample region using the beat frequency of the composite signal transmitting different wavelength channels.

10. The direction in which the system output signal travels away from the imaging system changes in response to operating the signal guiding section to change an alternative waveguide for receiving the emitted LIDAR signal. The imaging system according to claim 1.

11. The beam guiding section is configured to manipulate the system output signal within the field of view, the path of the system output signal within the field of view has a contribution from the beam guiding section and also has a contribution from the signal guiding section, the contribution from the beam guiding section to the path is a forward and backward movement across the field of view on the two-dimensional path of the system output signal, and the contribution from the signal guiding section to the path is a movement that crosses the contribution to the two-dimensional path provided by the beam guiding section of the system output signal. The imaging system according to claim 10.

12. The system according to claim 11, wherein the beam guiding section is a steerable mirror.

13. The beam guiding section is configured to scan the system output signal simultaneously on the slow axis and the fast axis, the beam guiding section scans the system output signal on the slow axis such that the direction in which the system output signal travels away from the LIDAR system changes at a slow angle, the beam guiding section scans the system output signal on the fast axis such that the direction in which the system output signal travels away from the LIDAR system changes at a fast angle, the ratio of the slow angle change speed to the fast angle change speed is greater than 2:1 and less than 200:

1. The system according to claim 12.

14. The contribution to the path from the beam guiding part is the movement in the zigzag pattern of the system output signal, the system according to claim 13.

Images