Imaging system with enhanced scan rate

Abstract

The LIDAR system includes a signal director that can direct an outgoing LIDAR signal to any of a plurality of different alternating waveguides. Each of the alternating waveguides is associated with a different switching channel, where an optical signal comprising light from an outgoing LIDAR signal directed to a particular one of the alternating waveguides may be characterized to carry the switching channel associated with that alternating waveguide. The LIDAR system is configured to output a system output signal comprising light from the outgoing LIDAR signal. And the system output signals bear different switching channels. The LIDAR system is configured to receive a system return signal comprising light from one of the system output signals after an object located outside the system receives and reflects the system output signals.

Description

[0001] Related Applications

[0002] This application is a continuation of U.S. patent application serial number 17 / 861,162, which was filed on July 8, 2022, entitled "Imaging System with Enhanced Scan Rate", and is incorporated herein in its entirety. Technical Field

[0003] The present invention relates to optical devices. In particular, the present invention relates to LIDAR systems. Background Art

[0004] As optical imaging systems support more and more applications, the performance requirements for optical imaging systems are also getting higher and higher. Optical imaging systems generally generate data for a series of sample areas, each of which is illuminated in turn by the system output signal. The data for the sample area indicates the radial velocity and / or distance between the imaging system and one or more objects located in the sample area. The imaging system can scan the system output signal to multiple different sample areas. The sample areas can be spliced ​​together to form the field of view of the imaging system. Therefore, the combination of data from different sample areas provides data for objects within the field of view.

[0005] Increasing the rate at which LIDAR data can be generated for different sample areas can increase the frequency at which the field of view can be scanned and / or can increase the resolution of the field of view. Thus, increasing the LIDAR data generation rate can increase the number of applications in which the LIDAR system can be successfully applied. However, increasing the LIDAR data generation rate generally increases the complexity and / or cost of the LIDAR system. Therefore, there is a need for improved LIDAR systems. Summary of the invention

[0006] The LIDAR system includes a signal director that can direct an outgoing LIDAR signal to any one of a plurality of different alternating waveguides. Each alternating waveguide is associated with a different switch channel, because an optical signal including light from an outgoing LIDAR signal directed to a specific one of the alternating waveguides can be characterized as carrying a switch channel associated with the alternating waveguide. The LIDAR system is configured to output a system output signal including light from the outgoing LIDAR signal. The system output signal carries different switch channels. The LIDAR system is configured to receive system return signals after an object located outside the system receives and reflects the system output signal, each system return signal including light from the system output signal. The signal combiner generates different composite signals by combining light from the system return signals carrying different switch channels with a reference signal. The electronic device calculates LIDAR data based on the frequency of one or more composite signals. The LIDAR system is configured to continue to generate a composite signal carrying a first switch channel for a considerable period of time after the imaging system has stopped outputting a system output signal carrying a first switch channel in the switch channels. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 An imaging system comprising a chip having a photonic circuit is shown.

[0008] Figure 2 A light source comprising a plurality of laser sources is shown.

[0009] Figure 3 is a schematic diagram of an imaging system including multiple different cores on a chip.

[0010] Figure 4A It is the frequency versus time plan used to adjust the wavelength channels in the system output signal.

[0011] Figure 4B yes Figure 4A A zoomed-in version of the frequency versus time plan shown in Figure 4A Part of one of the chirp cycles shown in .

[0012] Figure 5A and Figure 5B Shows a suitable Figure 1 An example of a signal processor in a constructed LIDAR system. Figure 5A is a schematic diagram of an example of a suitable optical-to-electrical assembly for a signal processor.

[0013] Figure 5B Provides electronic components and Figure 5ASchematic diagram of the relationship between optoelectronic components.

[0014] Figure 5C A portion of an electronic device is shown that includes components from a number of different signal processors.

[0015] 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.

[0016] Figure 6B Is from Fig. 6A Side view of an imaginary plane.

[0017] Figure 6C Is from Fig. 6A Another possible side view of the imaginary plane.

[0018] Figure 7 is a cross section of a silicon-on-insulator wafer.

[0019] Fig. 8A and Figure 8B An example of an optical switch comprising cascaded Mach-Zehnder interferometers is shown. Fig. 8A is a top view of a light switch.

[0020] Figure 8B It is along Fig. 8A The line marked B in Fig. 8A Cross-section of the optical switch shown in .

[0021] Fig. 9 Shows Figure 3 A LIDAR system is modified to have multiple signal directors, each signal director receiving a LIDAR output signal from a different core.

[0022] Fig.10 Shows Figure 3 LIDAR systems in which the light source is located outside the chip.

[0023] Fig.11 A portion of a LIDAR chip including a reference waveguide used in conjunction with a beam dump is shown. DETAILED DESCRIPTION

[0024] An imaging system has a signal director that can direct an outgoing LIDAR signal to any one of a plurality of different alternating waveguides. Each alternating waveguide can be associated with a different switching channel. An optical signal including light from an outgoing LIDAR signal directed to a particular one of the alternating waveguides can be characterized as carrying the switching channel associated with the alternating waveguide.

[0025] The system output includes a system output signal of light from the outgoing LIDAR signal. Thus, the system output signal can carry different switching channels. In some cases, the imaging system is configured such that the direction in which the system output signal travels away from the imaging system changes in response to a change in the alternating waveguide that receives the system output signal. Thus, the system output signal carrying different switching channels can travel away from the imaging system in different directions.

[0026] The imaging system receives system return signals. Each system return signal comprises light from one of the system output signals after an object located outside the system has received and reflected the system output signal. Thus, the system return signals carry different switching channels.

[0027] The imaging system generates different composite signals by combining light from system output signals carrying different switching channels with a reference signal. Thus, different composite signals can carry different switching channels. The imaging system may include an electronic device that calculates LIDAR data based on the frequency of one or more composite signals. The LIDAR data indicates 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.

[0028] The imaging system is capable of generating a composite signal carrying the first switching channel for a considerable period of time after the imaging system has stopped outputting the system output signal carrying the first switching channel in the switching channels. Thus, the imaging system can direct the outgoing LIDAR signal to a different one of the alternating waveguides while still being able to generate LIDAR data based on the composite signal carrying the first switching channel. Thus, the imaging system can output a system output signal carrying a second switching channel in the switching channels while being able to generate LIDAR data based on the composite signal carrying the first switching channel. The ability to generate LIDAR data carrying one switching channel while outputting system output signals carrying different switching channels reduces the time period required for the imaging system to output a system output signal carrying a particular channel. Thus, this ability can increase the frequency with which the field of view can be scanned and / or can increase the resolution of the field of view.

[0029] Figure 1 is a schematic diagram of a portion of a LIDAR system including a LIDAR chip 2 . Figure 1A top view of a portion of a LIDAR chip 2 is included. 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 outgoing LIDAR signal. The outgoing LIDAR signal includes one or more wavelength channels, each wavelength channel having a different wavelength. When the outgoing LIDAR signal carries more than one wavelength channel, the wavelengths of the wavelength channels can be periodically spaced, wherein the wavelength increase from one switching channel to the next switching channel is constant or substantially constant. Suitable light sources 10 for generating multiple wavelength channels with periodically spaced wavelengths include, but are not limited to, multiple single wavelength lasers multiplexed into a single optical waveguide, such as the light source described in U.S. patent application serial number 11 / 998,846 filed on November 30, 2017, which U.S. patent application patent number is 7542641, entitled "Multi-Switchchannel Optical Device", and is incorporated herein in its entirety.

[0030] The LIDAR chip includes a utility waveguide 12 that carries the outgoing LIDAR signal to a signal guide 14. The signal guide 14 can be operated by electronics to guide light from the outgoing LIDAR signal to one of a plurality of different alternating waveguides 16. There are N alternating waveguides, and each alternating waveguide 16 is associated with an alternating waveguide index i, where i has a value from 1 to N. Suitable values ​​for N include, but are not limited to, values ​​greater than or equal to 1, 2, or 3 and / or less than or equal to 128, 64, or 32. In one example, N is in the range of 1 to 128.

[0031] Each alternating waveguide 16 can receive an outgoing LIDAR signal from the signal director 14. When any of the alternating waveguides 16 receives an outgoing LIDAR signal, the alternating waveguide 16 acts as an active waveguide and carries the outgoing LIDAR signal to the port 18, through which the outgoing LIDAR signal can leave the LIDAR chip and act as a LIDAR output signal. Thus, the outgoing LIDAR signal is output from the active waveguide. Suitable ports include, but are not limited to, the facets of the alternating waveguides 16.

[0032] The outgoing LIDAR signal is guided to the alternating waveguide 16 with the alternating waveguide index i. The resulting optical signal can be regarded as carrying the switching channel (C i ) optical signal. Therefore, each LIDAR output signal is associated with a different one of the alternating waveguide index switching channel indices i=1 to N. For example, in Figure 1 In the example, the path carrying the LIDAR output signal of the switching channel with alternating waveguide index N is labeled SC N For illustration purposes, the LIDAR system is shown as generating a1 To SC N Each of the different LIDAR output signals may carry a different switching channel, but each of the different switching channels may carry the same (one or more) wavelength selections or substantially the same (one or more) wavelength selections.

[0033] Light from the LIDAR output signal travels away from the LIDAR system in the system output signal. In some cases, the portion of the LIDAR output signal that exits the LIDAR chip may also be considered the system output signal. As an example, when the LIDAR output signal exiting the LIDAR chip is also the LIDAR output signal exiting the LIDAR system, the LIDAR output signal may also be considered the system output signal.

[0034] The system output signal may travel through the atmosphere, the environment, and / or free space in the space in which the LIDAR system is located. The system output signal may 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 travels back toward the LIDAR chip as a system return signal.

[0035] Light from the system return signal can be carried in the LIDAR input signal received by the LIDAR chip. In some cases, a portion of the system return signal can serve as the LIDAR input signal.

[0036] The LIDAR input signal returns to the LIDAR chip, so that the carrier switching channel SC i The LIDAR input signal of the switching channel enters the alternating waveguide 16 associated with the same alternating waveguide index i. Therefore, the LIDAR input signals carrying different switching channels are directed to different alternating waveguides. The portion of the LIDAR input signal entering the alternating waveguide 16 acts as the incoming LIDAR signal. Therefore, the alternating waveguide receiving the incoming LIDAR signal can guide the outgoing LIDAR signal while also guiding the incoming LIDAR signal in the opposite direction. The alternating waveguide 16 receiving the incoming LIDAR signal carries a portion of the incoming LIDAR signal to the signal guide 14. The signal guide 14 outputs the received portion of the incoming LIDAR signal on the utility waveguide 12.

[0037] The alternate waveguide 16 carries the incoming LIDAR signal to a splitter 24, which moves a portion of the incoming LIDAR signal from the alternate waveguide 16 to 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 cases, the splitter 24 is configured to evenly or substantially evenly distribute the power of the incoming LIDAR signal between the utility waveguide 12 and the comparison waveguide 26.

[0038] The preliminary comparison waveguide 26 carries the preliminary comparison signal to a comparison demultiplexer 30. When the comparison optical signal includes a plurality of wavelength channels, the comparison demultiplexer 30 separates the comparison incoming LIDAR signal into different comparison signals, each different comparison signal carrying a different one of the wavelength channels. The comparison demultiplexer 30 outputs the comparison signals on different comparison waveguides 32. The comparison waveguides 32 each carry one of the comparison signals to a different signal processor 34. Thus, the signal processors 34 receiving the comparison signals from the same comparison demultiplexer 30 each receive a comparison signal carrying a different one of the wavelength channels.

[0039] The LIDAR chip includes a splitter 35 configured to move a portion of the outgoing LIDAR signal from the utility waveguide 12 to a reference signal waveguide 36. The portion of the outgoing LIDAR signal received by the reference signal waveguide 36 serves as a reference optical signal. The reference signal waveguide 36 carries the reference optical signal to a reference demultiplexer 38. When the reference optical signal includes multiple wavelength channels, the reference demultiplexer 38 divides the reference optical signal into different preliminary reference signals, each preliminary reference signal carrying a different one of the wavelength channels. The reference demultiplexer 38 outputs the preliminary reference signal on different reference waveguides 40. Suitable splitters 24 include, but are not limited to, wavelength-independent signal splitters, such as optical couplers, y-type connectors, MMIs, attenuated optical couplers, and star couplers. Suitable reference demultiplexers 38 include, but are not limited to, optical demultiplexers, such as arrayed waveguide gratings (AWGs) and trapezoidal gratings.

[0040] Reference waveguides 40 each carry one of the preliminary reference signals to a different splitter 42. Each splitter 42 splits the preliminary reference signal into a plurality of different reference signals, which are each output on a different reference waveguide 44. Reference waveguides 44 each carry one of the reference signals to a different one of signal processors 34. Suitable splitters 42 include, but are not limited to, wavelength-independent signal combiners such as optical couplers, y-junctions, MMIs, cascaded attenuated optical couplers, cascaded y-junctions, and start couplers.

[0041] The comparison waveguide 32 and the reference waveguide 44 are configured so that the comparison signal and the corresponding reference signal are received at the same signal processor 34. For example, the comparison waveguide 32 and the reference waveguide 40 are configured so that the comparison signal and the corresponding reference signal carrying the same wavelength channel are received at the same signal processor 34. Therefore, different signal processors 34 each receive the comparison signal and the reference signal carrying the same wavelength channel.

[0042] In addition, the comparison waveguide 32 and the reference waveguide 44 are configured so that each signal processor 34 receives a comparison signal and a reference signal carrying the same switching channel. Therefore, each signal processor 34 receives a comparison signal and a reference signal carrying the same switching channel and the same wavelength channel. In some cases, the comparison waveguide 32 and the reference waveguide 44 are configured so that each signal processor 34 receives a comparison signal and a reference signal having a unique combination of a switching channel and a wavelength channel. The signal processors 34 may be arranged in different switching channel groups 64. The signal processors 34 in the same switching channel group 64 each receive a comparison signal and a reference signal carrying the same switching channel. For example, the signal processors 34 in the same switching channel group 64 may receive signals carrying different wavelength channels but the same switching channel C. i The comparison signal and the reference signal.

[0043] As will be described in more detail below, signal processors 34 each combine the comparison signal with a corresponding reference signal to form a composite light signal that carries LIDAR data for a sample area on the field of view. Thus, the composite light signal may be processed to extract LIDAR data for the sample area.

[0044] The LIDAR chip may 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 outgoing LIDAR signal from the utility waveguide 12 to the control waveguide 68. The coupled portion of the outgoing LIDAR signal acts as a tap signal. Figure 1 A directional coupler 66 is shown moving a portion of the outgoing LIDAR signal to the control waveguide 68, but other signal tapping components may be used to move a portion of the outgoing LIDAR signal from the utility waveguide 12 to the control waveguide 68. Examples of suitable signal tapping components include, but are not limited to, y-junctions and MMIs.

[0045] The control waveguide 68 carries the tap signal to the control component 70. The control component may be in electrical communication with the electronics 62. Figure 1The electronics are shown as a separate component from the signal processor(s) 34, but a portion of the electronics may be included in each of the signal processor(s) 34. During operation, the electronics 62 may adjust the frequency of the outgoing LIDAR signal in response to the output of the control component. An example of a suitable configuration for the control component is provided in U.S. Patent Application Serial No. 15 / 977,957, filed May 11, 2018, entitled “Optical Sensor Chip,” and incorporated herein in its entirety.

[0046] When the splitter 24 is an optical coupler (e.g., a 2x2 coupler), the splitter can move a portion of the outgoing LIDAR signal onto the preliminary comparison waveguide 26. The preliminary comparison waveguide 26 can optionally terminate at a beam dump 72 that receives the coupled portion of the outgoing LIDAR signal. A suitable beam dump 72 can be configured to scatter the coupled portion of the outgoing LIDAR signal without reflecting a significant amount of light from the coupled portion of the outgoing LIDAR signal back into the preliminary comparison waveguide 26.

[0047] Figure 2 An example of a light source 10 including multiple laser sources 84 is shown. In some cases, each laser source 84 outputs one or more of the channels on a source waveguide 86. The source waveguide 86 carries the channels to a laser multiplexer 88, which 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, trapezoidal grating multiplexers, and star couplers. The electronics can operate the laser source 84 so that the laser source 84 outputs each channel simultaneously. The electronics can operate the laser source 84 so that the laser source 84 outputs each channel simultaneously.

[0048] In some cases, each laser source 84 outputs one of the wavelength channels on a source waveguide 86. Thus, each laser source 84 may be the source of a different one of the wavelength channels in the outgoing LIDAR signal and, thus, the system output signal.

[0049] The electronics can independently operate the laser sources 84. For example, the electronics can operate the laser sources 84 to provide a specific frequency-to-time waveform for the LIDAR output signal. Since the electronics can independently operate the laser sources 84, and each laser source 84 can be the source of a different one of the wavelength channels, the electronics can operate the laser sources 84 so that different wavelength channels in the outgoing LIDAR signal, and therefore the system output signal, have different frequency-to-time waveforms.

[0050] Suitable and according to Figure 2Laser sources 84 used with the constructed light source 10 include, but are not limited to, external cavity lasers, distributed feedback lasers (DFB), and Fabry-Perot (FP) lasers. External cavity lasers are advantageous in this embodiment because their line width is generally narrow, which can reduce noise in the detection signal.

[0051] The LIDAR system may include a LIDAR chip having one or more cores 4. For example, Figure 3 FIG. 1 shows a LIDAR chip including a plurality of different cores. The cores are each labeled as core k , where k represents the kernel index k. Each LIDAR kernel can be Figure 1 Each LIDAR core outputs a different LIDAR output signal. From the LIDAR core labeled k The LIDAR output signal of the core output can be used k,i where i represents the switching channel index. Therefore, S k,i is a function of the alternating waveguide index i and the core index k. For example, by S k,i The LIDAR output signal from the core k output and received by the alternating waveguide index i. Therefore, by S k,i The LIDAR output signal from the core k Output and carry switching channel SC i .

[0052] The LIDAR system can include an optical component assembly 75 that receives the LIDAR output signals from the different cores and outputs system output signals, each system output signal comprising, consisting of, or consisting essentially of light from a different one of the LIDAR output signals. The optical component assembly 75 can be operated by the electronics 280 to steer the system output signals to different sample areas in the LIDAR system field of view.

[0053] Figure 3 An optical component assembly 75 is shown, which includes a signal director 76 that receives each LIDAR output signal. The signal director 76 changes the direction of travel of at least a portion of the LIDAR output signals and outputs each LIDAR output signal as a redirected LIDAR output signal. Suitable signal directors 76 include, but are not limited to, convex lenses and concave mirrors. The optical component assembly 75 includes one or more beam directors 78 that receive the redirected LIDAR output signals output from the signal director 76 as system output signals. The system output signals travel in a direction away from the LIDAR system. Figure 3 Marked as d 2The electronics may operate one or more beam directors 78 to steer each system output signal to a different sample area in the field of view. Figure 3 As can be seen from the arrows marked A and B in FIG, one or more beam directors 78 can be configured to enable the electronics to steer the system output signal in one or two dimensions. Thus, one or more beam directors 78 can be used as a beam steering mechanism operated by the electronics to steer the system output signal within the field of view of the LIDAR system. Suitable beam directors 78 include, but are not limited to, movable mirrors, MEMS mirrors, optical phased arrays (OPAs), gratings, and actuated gratings. In some cases, the signal director 76 and / or one or more beam directors 78 are configured to operate on the system output signal so that the system output signal is collimated or substantially collimated when traveling away from the LIDAR system. Additionally or alternatively, the LIDAR system may include one or more collimating optical components (not shown) that operate on the LIDAR output signal, the redirected LIDAR output signal, and / or the system output signal so that the system output signal is collimated or substantially collimated when traveling away from the LIDAR system.

[0054] The system output signal may be reflected by an object located outside the LIDAR system. All or a portion of the reflected light from the system output signal may be returned to the LIDAR system as a system return signal. Each system return signal is received at one or more beam guides 78. One or more beam guides 78 output at least a portion of each system return signal as a return signal. Each return signal is received at a signal guide 76. The signal guide 76 outputs at least a portion of each return signal as a LIDAR input signal. Each different LIDAR input signal is received by a different core 4. Each LIDAR input signal includes light from a LIDAR output signal output from a core receiving the LIDAR input signal or consists of light from a LIDAR output signal output from a core receiving the LIDAR input signal. In addition, the LIDAR input signal received at the alternating waveguide includes light from a LIDAR output signal output from the same alternating waveguide or consists of light from a LIDAR output signal output from the same alternating waveguide.

[0055] The one or more signal directors 76 may redirect the direction of the LIDAR output signal traveling away from the one or more signal directors 76 so that the direction of the LIDAR output signal is different from the resulting redirected LIDAR output signal. In some cases, the one or more signal directors 76 are selected so that all or a portion of the redirected LIDAR output signal travels away from the one or more signal directors 76 in a non-parallel direction. For example, in Figure 3In one embodiment, one or more of the signal directors 76 are lenses, and each different LIDAR output signal is incident on the lens at a different angle of incidence. Therefore, the redirected LIDAR output signals each travel away from the signal directors 76 in a different direction. In addition, the redirected LIDAR output signals travel away from the signal directors 76 in non-parallel directions. Figure 3 It can be clearly seen that different directions of the system output signal can cause the system output signal to travel away from the LIDAR system in different directions. In some cases, the system output signal travels away from the LIDAR system in non-parallel directions.

[0056] Operating the signal director 14 on a core may change the location at which one or more signal directors 76 receive the LIDAR output signal and may accordingly change the direction in which the system output signal originating from that core travels away from the LIDAR system. Figure 3 The dashed line in the core shows 1 As a result of operating the signal director 14, the nuclear output is S k,i+1 The LIDAR output signal is represented by S k,i Represents the LIDAR output signal. Figure 3 It can be clearly seen that this operation of the signal director 14 changes the core 1 The output system output signal is away from the direction of travel of the LIDAR system. Therefore, the electronic device can operate the signal director 14 on different cores to steer the system output signal within the field of view of the LIDAR system. Therefore, the electronic device can operate the signal director 14 and / or one or more beam directors 78 on different cores to steer the system output signal within the field of view of the LIDAR system. Suitable methods for operating signal directors 14 and / or one or more beam directors 78 on different cores to steer the system output signal to different sample areas within the field of view of the LIDAR system are disclosed in U.S. patent application serial number 17 / 580,623, entitled "Imaging System with Multiple Cores," filed on January 20, 2022, which is incorporated herein in its entirety.

[0057] The optical component assembly 75 may have Figure 3 Configurations other than those shown. For example, one or more beam guides 78 can be located between the signal guide 76 and the LIDAR chip. In addition, the optical component assembly 75 can include optical components that are not shown. For example, the optical component assembly 75 can include one or more lenses that are configured to increase the collimation of the LIDAR output signal and / or other signals derived from the LIDAR output signal and / or light including the LIDAR output signal.

[0058] The wavelengths of the LIDAR output signals output from different cores can be the same or different. Thus, the light sources on different cores can be configured to output outgoing light signals, each outgoing light signal having a different, the same, or substantially the same wavelength selection. Thus, the wavelength selection in the output signals of different systems can be different, the same, or substantially the same.

[0059] All or part of the electronics 62 associated with different cores may optionally be combined in Figure 3 The combined electronics 280 may be located on the LIDAR chip, or may be located external to the LIDAR chip. The combined electronics 280 may collect or generate LIDAR data results from different cores, and / or may coordinate LIDAR data results from different cores to assemble LIDAR data results for the LIDAR system field of view.

[0060] although Figure 3 Four cores on the LIDAR chip are shown, but the LIDAR chip may include one, two, or more than two cores. Suitable numbers of cores on the LIDAR chip include, but are not limited to, numbers greater than or equal to 1, 2, 4, or 6 and / or less than 32, 64, or 128.

[0061] During operation of the LIDAR system, the electronics chirp the frequency of one or more wavelength channels in the system output signal. Figure 4A and Figure 4B An example of a frequency versus time schedule for adjusting wavelength channels in a system output signal is provided. The system output signal is shown as carrying a wavelength channel labeled λ j where j is the wavelength channel index, which has a value from 1 to M, where, in this example, M=3. In some cases, the fundamental frequencies of the wavelength channels are separated by Δf. The frequencies are adjusted so that there is no overlap in the frequencies of different wavelength channels. The system output signal λ 1 and λ 2 Each has a chirping frequency, where the frequency varies with time. The system output signal λ 1 and λ 2 The chirping is completed in a series of chirp cycles, and the duration of each chirp cycle is marked as CP. Figure 4B yes Figure 4A A zoomed-in version of the frequency versus time plan shown in Figure 4A A portion of a chirp cycle is shown in .

[0062] At least two of the wavelength channels have frequencies that chirp at different rates and / or in different directions. For example, during a chirp cycle, the wavelength channel λ 1 and λ 2The chirp of the system output signal can be an upward chirp with an increase in frequency or a downward chirp with a decrease in frequency. During the chirp cycle, the wavelength channel λ 1 or 2 The chirp of the system output signal has a linear chirp part between the nonlinear chirp parts. The nonlinear chirp part can be the product of changing the chirp direction at the junction between the chirp cycles. The duration of the linear chirp part is Figure 4A Marked as cp n , where n is the cycle index. In some cases, the duration of the linear chirp portion is greater than 5 μs, 10 μs, or 100 μs and / or less than 200 μs, 500 μs, or 1000 μs. In some cases, the duration of the linear chirp portion is greater than 5, 10, or 100 times and / or less than 200, 500, or 1000 times the total duration of one or more nonlinear chirp portions included in the chirp cycle.

[0063] During the same chirp cycle, the wavelength channel λ 1 and λ 2 The frequency of the output signals of the IRQ2000 is changed in opposite directions but at the same rate. Therefore, the sample area is illuminated by at least one wavelength channel with increasing frequency and at least one wavelength channel with decreasing frequency at the same rate of frequency change.

[0064] The bearer is marked as λ 3 The wavelength channel of the system output signal is optional. Although marked as λ 3 The system output signal is shown to have a non-chirped frequency, but carries λ 3 The system output signal can have a chirped or non-chirped frequency. 3 When the system output signal has a chirped frequency, the rate and / or direction of the frequency chirp may be different from the system output signal λ 1 The rate and direction of the frequency chirp can also be different from the system output signal λ 2 The rate and direction of the frequency chirp.

[0065] The system output signal is output during a plurality of different output cycles. The composite light signal generated in response to the output of the system output signal during an output cycle is used to generate LIDAR data for that output cycle. The LIDAR data for the output cycle indicates radial velocity and / or distance between the LIDAR system and one or more objects that reflected the system output signal output during the output cycle. Figure 4A In the example, different output cycles are marked as p k , where k is an output cycle index, whose value is greater than or equal to 1. The output cycles may occur serially. In some cases, there is no delay or substantially no delay between output cycles that are adjacent to each other in time in the same chirp cycle.

[0066] The output cycles may each have the same or substantially the same duration. In some cases, the duration of the output cycles is greater 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 portion may be greater 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 cycles.

[0067] As described above, the system output signal can be steered to different sample regions in the field of view of the LIDAR system. The sample regions can each be associated with one of the output cycles. For example, a sample region can be a volume of the field of view that is illuminated by the system output signal output during the output cycle associated with the sample region and that extends from the maximum operating distance of the LIDAR system.

[0068] At the end of each output cycle, the electronic device can operate the signal director 14 to switch the alternate waveguide 16 receiving the light source output signal. Therefore, the switching channel carried by the light source output signal changes when the output cycle changes. Therefore, the switching channel carried by the system output signal is different for adjacent output cycles. Figure 3 As noted in the case of FIG. 1 , switching alternate waveguides 16 that receive the light source output signal and / or changing the switching channel that the system output signal carries changes the direction in which the system output signal travels away from the LIDAR system. Thus, a change in the output period is associated with a change in the sample area illuminated by the system output signal. Thus, each output period is associated with a different one of the sample areas.

[0069] review Figure 1 , it can be seen that after the alternating waveguide 16 receiving the light source output signal is changed and / or the switching channel carrying the system output signal is changed, the signal processor 34 in the same switching channel group 64 continues to receive the comparison signal and the reference signal. Therefore, when different alternating waveguides in the alternating waveguides are receiving the light source output signal, the channel group 64 associated with the alternating waveguide index i can generate a composite signal. Therefore, the same core in the LIDAR system can simultaneously receive system return signals carrying different switching channels, and the signal processor 34 on the core can simultaneously process the composite signal carrying different switching channels.

[0070] Figure 4BThe ability of a LIDAR system to simultaneously process system return signals carrying different switching channels is shown. A LIDAR system is typically configured to provide reliable LIDAR data when an object is within an operating distance range from the LIDAR system. The operating distance range may extend from a minimum operating distance to a maximum operating distance. The maximum round trip time may be the time required for a system output signal to leave the LIDAR system, travel the maximum operating distance to an object having a surface at the maximum operating distance, and return to the LIDAR system. Examples of possible maximum round trip times are shown in FIG. Figure 4B The symbol is τ M When an object has a surface located at the maximum operating distance, the system return signal caused by the surface will not be returned to the LIDAR system until the maximum round trip time has passed. For example, when the duration of the maximum round trip time is between the duration of two and three output cycles (such as Figure 4B As shown), and the object is in the output cycle p k When the LIDAR system has a surface at the maximum operating distance, it will not generate a composite optical signal from the surface until the output period p k+2 End and output cycle p k+3 Thus, the duration of two output cycles has elapsed before LIDAR data is generated for a surface located at the maximum operating distance. However, when an object has a surface located at a distance less than the maximum operating distance from the LIDAR system, LIDAR data may be generated earlier. For example, an object may be located close enough to the LIDAR system that a composite light signal from the object appears early enough to be detected at the time labeled p k The LIDAR data is generated in an output cycle of . In some cases, the duration of the output cycle can be greater 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.

[0071] Figure 4B The top portion of the graph includes multiple horizontal rectangles, each associated with a different one of the output cycles. Each rectangle represents a data cycle and includes multiple different time zones. The rectangles are divided into multiple segments, each of which is labeled with a different time that passes within the segment. For example, one segment in each data cycle is labeled p k / τ M This segment indicates the output period p k The position relative to the time scale on the x-axis. Label τ M It also indicates the maximum round trip time (τ M ) starts from the beginning of the time period. Another segment in each data cycle is labeled τ M , and indicates the maximum round trip time (τ M) duration (tolling). Maximum round trip time (τ M ) terminates during this time period.

[0072] Since there is a delay between the transmitted system output signal and the resulting system return signal back to the LIDAR system, the composite signal does not include a contribution from the LIDAR signal until after the system return signal returns to the LIDAR system. Since the composite signal requires a contribution from the system return signal so that a beat frequency is present, the electronics uses the composite signal that occurs after the system return signal returns to the LIDAR system to generate the LIDAR data. The composite signal needs to exist for a period of time (the measurement period, w) in order for the electronics to measure the beat frequency of the composite signal. Therefore, Figure 4B Each data cycle shown in comprises a segment marked w.

[0073] exist Figure 4B In the example, the measurement period (w) is located at the end of the data period to illustrate the total duration of the data period when the object is at the maximum operating distance. However, the actual location of the measurement period (w) in the data period can change in response to the proximity of the object to the LIDAR system. For example, the closer the object moves toward the LIDAR system, the earlier the measurement period (w) occurs in the data period.

[0074] exist Figure 4B In the example, each data cycle is associated with a switching channel label SC 1 To SC 4 Therefore, Figure 4B The core shown in has N = 4 alternating waveguides. Therefore, with the switching channel label SC 2 The associated data cycle includes the output cycle p k+1 During this period, Figure 1 The alternating waveguide 16 labeled i=2 in FIG. 1 receives the outgoing LIDAR signal from the signal director 14. However, in the output period p k+1After termination, the outgoing LIDAR signal is not received at the alternating waveguide 16 labeled i=2 because the signal director 14 directs the outgoing LIDAR signal toward the alternating waveguide 16 labeled i=3. However, the LIDAR system continues to generate a composite signal carrying the first of the switching channels for a considerable period of time after the imaging system has stopped outputting the system output signal carrying the first switching channel i=2. For example, the LIDAR system may continue to generate a composite signal carrying the first of the switching channels for a period exceeding 0.1, 1, 1.3, or 1.5 times the output period after the imaging system has stopped outputting the system output signal carrying the first switching channel. In some cases, the LIDAR system stops generating a composite signal carrying the first of the switching channels in a period less than 2, 4, or 6 times the output period after the imaging system has stopped outputting the system output signal carrying the first switching channel. Thus, the system may direct the outgoing LIDAR signal to a different one of the alternating waveguides while still being able to generate LIDAR data based on the composite signal carrying the first of the switching channels. Therefore, the system can output a system output signal carrying the second of the switched channels, while being able to generate LIDAR data based on the beat frequency of the composite signal carrying the first switched channel. Figure 4B As shown, in some cases, the system can output a system output signal carrying a third of the switching channels, while being able to generate LIDAR data according to the beat frequency of the composite signal carrying the first switching channel, and also simultaneously being able to generate LIDAR data according to the beat frequency of the composite signal carrying the second switching channel. Therefore, the system can output a system output signal carrying the third of the switching channels, while being able to generate LIDAR data according to the beat frequency of the composite signal carrying the first switching channel, and simultaneously being able to generate LIDAR data according to the beat frequency of the composite signal carrying the second switching channel, and simultaneously being able to generate LIDAR data according to the beat frequency of the composite signal carrying the third switching channel. Therefore, in some cases, the system can simultaneously generate LIDAR data according to the beat frequencies of two or more different composite signals, each different composite signal carrying a different one of the switching channels. The ability to generate LIDAR data carrying one switching channel while outputting system output signals carrying different switching channels reduces the time period required for the imaging system to output a system output signal carrying a particular channel.

[0075] exist Figure 4B There is a switch channel label SC 1 The second occurs because the electronics direct the outgoing LIDAR signal to alternate waveguides 16 labeled i=1 through i=N in sequence before returning to alternate waveguide 16 labeled i=1, and repeating the sequence. iThe associated data cycle is until the same switching channel (SC i ) is started after the previous data cycle associated with the switching channel i ends to prevent the signal processors in the switching channel group 64 associated with the switching channel i from being overlapped. Figure 4B In the middle, marked as SC 1 The data cycles do not overlap.

[0076] FIG. 5A to FIG. 5B Shows a suitable Figure 1 An example of a signal processor 34 of any signal processor 34 in a constructed LIDAR system. The signal processor 34 includes an optoelectronic component configured to convert an optical signal into an electrical signal. Figure 5A is a schematic diagram of an example of a suitable optoelectronic component, which includes a first splitter 200 that distributes the comparison signal received from the comparison waveguide 32 onto a first comparison waveguide 204 and a second comparison waveguide 206. The first comparison waveguide 204 carries a first portion of the comparison signal to an optical combination component 211. The second comparison waveguide 206 carries a second portion of the comparison signal to a second optical combination component 212.

[0077] Figure 5A The signal processor also includes a second splitter 202 that distributes the reference signal received from the reference waveguide 44 to a first reference waveguide 210 and a second reference waveguide 208. The first reference waveguide 210 carries a first portion of the reference signal to an optical combination component 211. The second reference waveguide 208 carries a second portion of the reference signal to a second optical combination component 212.

[0078] The second optical combining component 212 combines the second part of the comparison signal and the second part of the reference signal into a second composite signal. Due to the frequency difference between the second part of the comparison signal and the second part of the reference signal, the second composite signal oscillates between the second part of the comparison signal and the second part of the reference signal.

[0079] The second optical combining component 212 also splits the resulting second composite signal onto a first auxiliary detector waveguide 214 and a second auxiliary detector waveguide 216. The first auxiliary detector waveguide 214 carries a first portion of the second composite signal to a first auxiliary optical sensor 218, which converts the first portion of the second composite signal into a first auxiliary electrical signal. The second auxiliary detector waveguide 216 carries a second portion of the second composite signal to a second auxiliary optical sensor 220, which 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).

[0080] In some cases, the second optical combination component 212 divides the second composite signal so that the portion of the comparison signal included in the first portion of the second composite signal (i.e., the portion of the second portion of the comparison signal) is phase-shifted by 180° relative to the portion of the comparison signal in the second portion of the second composite signal (i.e., the portion of the second portion of the comparison signal), but the portion of the reference signal in the second portion of the second composite signal (i.e., the portion of the second portion of the reference signal) is not phase-shifted relative to the portion of the reference signal in the first portion of the second composite signal (i.e., the portion of the second portion of the reference signal). Alternatively, the second optical combination component 212 divides the second composite signal so that the portion of the reference signal in the first portion of the second composite signal (i.e., the portion of the second portion of the reference signal) is phase-shifted by 180° relative to the portion of the reference signal in the second portion of the second composite signal (i.e., the portion of the second portion of the reference signal), but the portion of the comparison signal in the first portion of the second composite signal (i.e., the portion of the second portion of the comparison signal) is not phase-shifted relative to the portion of the comparison signal in the second portion of the second composite signal (i.e., the portion of the second portion of the comparison signal). Examples of suitable optical sensors include germanium photodiodes (PDs) and avalanche photodiodes (APDs).

[0081] The first optical combining component 211 combines the first part of the comparison signal and the first part of the reference signal into a first composite signal. Due to the frequency difference between the first part of the comparison signal and the first part of the reference signal, the first composite signal oscillates between the first part of the comparison signal and the first part of the reference signal.

[0082] The optical combining component 211 also separates the first composite signal onto a first detector waveguide 221 and a second detector waveguide 222. The first detector waveguide 221 carries a first portion of the first composite signal to a first optical sensor 223, which converts the first portion of the second composite signal into a first electrical signal. The second detector waveguide 222 carries a second portion of the second composite signal to a second optical sensor 224, which 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).

[0083] In some cases, the optical combination component 211 splits the first composite signal so that a portion of the comparison signal included in the first portion of the composite signal (i.e., a portion of the first portion of the comparison signal) is phase-shifted by 180° relative to a portion of the comparison signal in the second portion of the composite signal (i.e., a portion of the first portion of the comparison signal), but a portion of the reference signal in the first portion of the composite signal (i.e., a portion of the first portion of the reference signal) is not phase-shifted relative to a portion of the reference signal in the second portion of the composite signal (i.e., a portion of the first portion of the reference signal). Alternatively, the optical combination component 211 splits the composite signal so that a portion of the reference signal in the first portion of the composite signal (i.e., a portion of the first portion of the reference signal) is phase-shifted by 180° relative to a portion of the reference signal in the second portion of the composite signal (i.e., a portion of the first portion of the reference signal), but a portion of the comparison signal in the first portion of the composite signal (i.e., a portion of the first portion of the comparison signal) is not phase-shifted relative to a portion of the comparison signal in the second portion of the composite signal (i.e., a portion of the first portion of the comparison signal).

[0084] When the second optical combination component 212 divides the second composite signal so that the portion of the comparison signal in the first portion of the second composite signal is phase-shifted by 180° relative to the portion of the comparison signal in the second portion of the second composite signal, the optical combination component 211 also divides the composite signal so that the portion of the comparison signal in the first portion of the composite signal is phase-shifted by 180° relative to the portion of the comparison signal in the second portion of the composite signal. When the second optical combination component 212 divides the second composite signal so that the portion of the reference signal in the first portion of the second composite signal is phase-shifted by 180° relative to the portion of the reference signal in the second portion of the second composite signal, the optical combination component 211 also divides the composite signal so that the portion of the reference signal in the first portion of the composite signal is phase-shifted by 180° relative to the portion of the reference signal in the second portion of the composite signal.

[0085] The first reference waveguide 210 and the second reference waveguide 208 are configured 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 configured to provide a 90 degree phase shift between the first portion of the reference signal and the second portion of the reference signal. For example, one reference signal portion can be an in-phase component and the other reference signal portion can be an orthogonal component. Therefore, 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 configured so that the first reference signal portion is a cosine function and the second reference signal portion is a sine function. Therefore, a portion of the reference signal in the second composite signal is phase shifted relative to a portion of the reference signal in the first composite signal, however, a portion of the comparison signal in the first composite signal is not phase shifted relative to a portion of the comparison signal in the second composite signal.

[0086] The first light sensor 223 and the second light sensor 224 may be connected as a balanced detector, and the first auxiliary light sensor 218 and the second auxiliary light sensor 220 may also be connected as a balanced detector. Figure 5B A schematic diagram of the relationship between the electronics, first light sensor 223, second light sensor 224, first auxiliary light sensor 218, and second auxiliary light sensor 220 is provided. The symbol of a photodiode is used to represent the first light sensor 223, second light sensor 224, first auxiliary light sensor 218, and second auxiliary light sensor 220, but one or more of these sensors may have other configurations. In some cases, Figure 5B All components shown in the schematic are included on the LIDAR chip. In some cases, Figure 5B The components shown in the schematic diagram are distributed between the LIDAR chip and the electronics located outside the LIDAR chip. The balanced detector can be operated as a light sensor because it converts light signals into electrical signals.

[0087] The electronics connect the first light sensor 223 and the second light sensor 224 as a first balanced detector 225, and connect the first auxiliary light sensor 218 and the second auxiliary light sensor 220 as a second balanced detector 226. In particular, the first light sensor 223 and the second light sensor 224 are connected in series. In addition, the first auxiliary light sensor 218 and the second auxiliary light sensor 220 are connected in series. The series connection in the first balanced detector communicates with the first data line 228, which carries the output from the first balanced detector as a first data signal. The series connection in the second balanced detector communicates with the second data line 232, which carries the output from the second balanced detector as a second data signal. The first data signal is an electrical representation of the first composite signal, and the second data signal is an electrical 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 relative to the portion of the first waveform in the first data signal, but the portion of the second waveform in the first data signal is in phase relative to 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 relative to a different portion of the reference signal included in the first data signal. In addition, the second data signal includes a portion of the comparison signal that is in phase with a different portion of the comparison signal included in the first data signal. The first data signal and the second data signal beat due to the beat between the comparison signal and the reference signal, i.e., the beat in the first composite signal and the second composite signal.

[0088] The electronic device 62 includes a transformation 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 with the first data signal and the second data signal as input. Since the first data signal is an in-phase component and the second data signal is its orthogonal component, the first data signal and the second data signal together act as a complex data signal, wherein the first data signal is the real part of the input and the second data signal is the imaginary part of the input.

[0089] The conversion mechanism 238 includes a first analog-to-digital converter (ADC) 264, which 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 an analog form to a digital form and outputs a first digital data signal. The conversion mechanism 238 includes a second analog-to-digital converter (ADC) 266, which 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 an analog form to a 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. Therefore, the first digital data signal and the second digital data signal together act as a complex signal, wherein the first digital data signal acts as the real part of the complex signal, and the second digital data signal acts as the imaginary part of the complex data signal.

[0090] The transformation mechanism 238 includes a mathematical transformer 268 that receives a complex data signal. For example, the mathematical transformer 268 receives a first digital data signal from a first analog-to-digital converter (ADC) 264 as an input, and also receives a second digital data signal from a first analog-to-digital converter (ADC) 266 as an input. The mathematical transformer 268 can be configured to perform a mathematical transformation on the complex signal to convert from the time domain to the frequency domain. The mathematical transformation can be a complex transformation, such as a complex fast Fourier transform (FFT). A complex transformation (such as a complex fast Fourier transform (FFT)) provides a clear solution for comparing the frequency shift of a signal relative to a system output signal.

[0091] The transformation mechanism 238 includes a peak finder 270 that receives the output from the mathematical transformer 268. The peak finder 270 searches for peaks in the output of the mathematical transformer 268 to identify one or more peaks in the beat frequency of the composite optical signal.

[0092] The electronic device is configured to combine the outputs from different signal processors 34 to generate LIDAR data. For example, the electronic device can combine the beat frequencies from different signal processors 34 to generate LIDAR data. In particular, the electronic device can combine the beat frequencies of multiple wavelength channels associated with the same switching channel to generate LIDAR data of the output period. For example, Figure 5C A portion of the electronics including a mathematical transformer 268 from a different signal processor is shown.

[0093] The mathematical transformers 268 are shown as being arranged in different switching channel groups 64. Thus, the mathematical transformers 268 in the same switching channel group are each associated with a different wavelength channel, but are associated with the same switching channel. Thus, each mathematical transformer 268 is labeled with the wavelength channel index (λ) associated with the mathematical transformer. j ) and switching channel index (j).

[0094] The electronic device includes a plurality of LIDAR data generators 272. Each LIDAR data generator 272 receives a beat frequency from a peak finder 270 in the same switching channel group 64. For example, the electronic device is configured so that one of the LIDAR data generators 272 receives a beat frequency associated with a different wavelength channel (λ 1 To M ) and is also associated with channel i=1, while another one of the LIDAR data generators 272 receives a beat frequency associated with a different wavelength channel (λ 1 To M ) and is also associated with channel i=2. Thus, each LIDAR data generator 272 may be associated with a different one of the switching channels.

[0095] Each LIDAR data generator 272 combines the beat frequencies from different wavelength channels resulting from the same output cycle to generate the LIDAR data for that output cycle. For example, the following equation applies to wavelength channels where the frequency of the system output signal carrying that channel increases during the output cycle, e.g., for Figure 5B The LIDAR output signal λ 1 In the output cycle c 1 During the period: +f ub =-f d +ατ 0 , where f ub is the beat frequency of the peak finder output for that channel during the output cycle, f d represents the Doppler frequency shift (f d =2vf c / c), where f c is the frequency of the LIDAR output signal at the beginning of the output cycle, v is the radial velocity between the reflecting object and the LIDAR chip, where the direction from the reflecting object toward the chip is assumed to be the positive direction, and c is the speed of light, α represents the rate at which the outgoing LIDAR signal frequency increases or decreases during the output cycle, and τ 0 is the round trip delay of the stationary reflecting object (the time between the system output signal leaving the LIDAR system and the system return signal returning to the LIDAR system). The following equation applies to channels with a reduced frequency of carrying the system output signal of that channel during the output cycle, e.g., for a period of output cycle c 1 period Figure 5B The LIDAR output signal λ 2 Case: -f db =-f d -ατ 0 , where f dbis the beat frequency of the channel output in the peak finder during the output cycle. In both equations, f d and τ 0 These two equations are for two unknowns f d and τ 0 Solve it. Substitute the solution f db and f ub The values ​​of f come from different signal processors 34, because f db The values ​​of are generated based on the LIDAR output signal carrying different wavelength channels, rather than on the generation of f ub The LIDAR output signal of the value is generated. Different wavelength channels are incident on the same sample area at the same time. Then the Doppler frequency shift (v = c*f d / (2f c )) determines the radial velocity of the output cycle and can be calculated based on c*τ 0 / 2 determines the separation distance of the sample region. Thus, the wavelength channels received at different signal processors can be used to determine the LIDAR data for a single output cycle.

[0096] As described above, the LIDAR system can be configured to operate at a maximum operating distance. When generating LIDAR data, the electronics can filter out beat frequencies output from the peak finder that are above a threshold associated with the maximum operating distance. For example, the electronics can discard beat frequencies output from the peak finder that are above a threshold.

[0097] As described above, the LIDAR system may output a system output signal carrying two or more wavelength channels. For example, the LIDAR system may carry three channels having wavelengths according to Figure 4A and Figure 4B A frequency versus time waveform of the LIDAR system. This may be desirable in the case where the composite optical signal carries light reflected by multiple different objects during an output period. The different reflecting objects in the sample area need not be physically separate items, but can be different surfaces of the same item that are located at different distances from the LIDAR system and / or move at different radial velocities relative to the LIDAR system, as would occur with a jagged object that rotates and translates relative to the LIDAR system.

[0098] In the case where the composite optical signal carries light reflected by multiple different objects during an output cycle, the mathematical transformer 268 may output more than one frequency value, where each different frequency value is associated with a different one of the reflecting objects. In these cases, it may be necessary to match the beat frequencies provided by the peak finders 270 in the different signal processors. The matching is performed so that the matched frequencies are frequencies from the same reflecting object. A frequency converter such as λ may be used. 3Additional channels are provided to match the frequencies. LIDAR data may be generated for each pair of matched frequencies and viewed and / or processed as LIDAR data for different reflecting objects.

[0099] An example of a LIDAR system includes a light source configured to generate a system output signal carrying three wavelength channels. One of the system output signals carries a frequency versus time relationship consistent with Figure 4A The channel λ in 1 The wavelength channel of the other LIDAR output signal carries a frequency-time relationship that conforms to Figure 4A The channel λ in 2 The channel, and the other LIDAR output signal carries a frequency-time relationship that meets Figure 4A The channel λ in 3 In this example, the receiving channel λ 3 The beat frequency of the peak finder output associated with the signal processor is: 3 =-f d +α”τ 0 , where f d represents the Doppler frequency shift, α” represents the LIDAR output signal λ 3 The rate at which the frequency increases or decreases during an output cycle, and τ 0 represents the round trip delay. 3 The frequency-time relationship is consistent with Figure 4B When α”=0, the equation simplifies to f 3 =-f d For f 3 The equation can be used to generate theoretical f for at least some of the possible frequency pairs 3 , and the theoretical f 3 The value is associated with the receiving channel λ 3 The peak finder of the signal processor provides the actual f 3 The value closest to the actual f 3 Theoretical value of f 3 Frequency pairs of values ​​are considered matching pairs. LIDAR data may be generated for each matching pair, and the LIDAR data from the matching pair may be considered and / or processed as LIDAR data for each different reflecting object in the sample area.

[0100] As an example of matching pair identification, with the receiving wavelength channel λ 1 The mathematical transformer 168 associated with the signal processor 34 outputs two different f db Frequency: f d11 and f d12 In addition, with the receiving channel λ 2The signal processor associated with the peak finder outputs two different f db Frequency: f d21 and f d22 In this example, the possible frequency pairs are: (f d11 ,f d21 );(f d11 ,f d22 );(f d12 ,f d21 ); and (f d12 ,f d22 ). f can be calculated for each of the four possible frequency pairings above d and τ 0 The value of f d and τ 0 The value of can be substituted into f 3 =-f d +α”τ 0 Generate a theoretical pair for each possible frequency f 3 As mentioned above, when α” = 0, the equation simplifies to f 2 =-f d In these examples, there is no need to calculate τ for possible frequency pairings 0 . With the receiving channel λ 3 The signal processor associated with the mathematical transformer 168 also outputs two f 3 values, each of which is considered to be the actual f 3 value. The value closest to each actual f 3 Theoretical value of f 3 Frequency pairs of values ​​are considered matching pairs. LIDAR data may be generated for each matching pair as described above and considered and / or processed as LIDAR data for different reflecting objects in the sample area.

[0101] Although the mathematical transformer 268 is disclosed as performing a complex transform on a complex signal, the complex transform may be replaced by a real transform performed on a real signal. Figure 5A The optoelectronic components are configured to exclude the second optical combination component 212, the comparison waveguide 206, the second separator 202 and the second reference waveguide 208.

[0102] Fig. 6A FIG. 1 is a schematic diagram of the relationship between a LIDAR system including a single LIDAR core (not shown) and the field of view. The field of view is represented by a dotted line extending from the LIDAR system to an imaginary surface within the field of view. To show the extent of the field of view, the imaginary surface is located at the maximum operating distance (labeled d ) of the LIDAR system. M ) place.

[0103] As described above, a LIDAR system may include one or more beam directors ( FIG. 6A to FIG. 6C ), which redirects the system output signal to different sample areas 300 in the field of view. A portion of the sample area is Fig. 6A The rectangle on the plane is shown. The electronics generates LIDAR data in a series of cycles by sequentially illuminating different sample areas in the field of view of the LIDAR system. LIDAR data can be generated for each sample area.

[0104] exist Fig. 6A In FIG. 1 , only a portion of the sample area shown is shown illuminated by the system output signal because the system output signal may continue to be scanned during the output cycle associated with the sample area. For example, the system output signal may be scanned in the direction of the arrow marked A for the duration of the output cycle. Fig. 6A The scan may cause the system output signal to illuminate the length of the plane labeled ct during an output period.

[0105] Figure 6B yes Fig. 6A A LIDAR system can include multiple steering mechanisms ( FIG. 6A to FIG. 6C ), which steers the system output signal to different sample areas in the field of view. Figure 6B The dotted line in the figure represents the bearer switching channel SC 2 The centroid response of the system output signal is determined only by Figure 3 One or more beam directors 78 disclosed herein steer the system output signal to travel through a plane in the field of view. A sample area 300 is represented by a rectangle positioned along the system output signal path.

[0106] Figure 6B The scanning path of the system output signal shown in has a fast axis, which is determined by Figure 6B The arrow marked “fast” indicates. Figure 6B The scanning path of the system output signal shown in has a slow axis, which is determined by Figure 6B The arrow marked as "slow" in FIG. 1 indicates that the scanning speed of the system output signal in the fast axis direction is faster than the scanning speed of the system output signal in the slow axis direction.

[0107] In order to obtain LIDAR data results that are representative of the entire field of view, it is generally desirable to match the number of sample areas in the fast axis direction with the number of sample areas in the slow axis direction. The scanning speed in the fast direction can be increased to increase the number of zigzags that the system output signal travels through the field of view. The increased number of zigzags provides an increased number of sample areas in the fast axis direction. However, as the application of LIDAR systems has increased, the required field of view size and maximum operating distance have increased to a size where the required scanning speed of one or more beam directors 78 is impossible or impractical and / or has undesirable high power requirements.

[0108] Figure 6C yes Fig. 6A Side view of the imaginary plane in . Figure 6C The dotted line in the figure indicates that when the bearer switching channel SC 2 The system output signal is only Figure 3 The path of the centroid of the system output signal when steered by one or more beam directors 78 (beam directors) as disclosed above and below. Figure 6C The sample regions of are vertically separated from each other and from the path provided by the beam director, as shown by the dashed lines. The vertical separation is caused by the electronics of the signal director 14 operating to change the direction in which the system output signal travels away from the LIDAR system. Thus, operation of the signal director 14 shifts the system output signal in a direction transverse to the path provided by the beam director. For example, the sample region 129 labeled SRi may represent the sample region when the signal director 14 is operated so that the system output signal carries channel Ci. From Figure 6C As is apparent from the sequence of sample regions shown, the signal director 14 is operated so that the system output signal carries the switching channels Ci in order from i=1 to N, and the sequence is repeated. Figure 6C The switching channel sequence is shown in forward order, but the channel sequence may be repeated in reverse order. Thus, a forward order sequence (i=1 to N) may alternate with a reverse order sequence (i=N to 1).

[0109] The scanning speed on the fast axis can be relative to Figure 6B The fast axis scan speed of the system is slowed down while maintaining the same frame rate (the rate at which each sample area in the field of view is illuminated by the system output signal). Figure 6C The fast axis scanning speed is about Figure 6B The fast axis scanning speed is 1 / N times the fast axis scanning speed of the LIDAR image sensor, where N is the number of alternating waveguides 16. The reduction in the fast axis scanning speed can be seen from the reduction in the number of zigzags within the same frame scanning time (1 / frame rate). As the fast axis scanning speed is reduced, the length of the sample area in the fast axis direction is reduced, and therefore the size is reduced. The reduction in the size of the sample area leads to an increase in the reliability of the LIDAR data.

[0110] exist Figure 6B In , the distance that the system output signal travels along the fast axis during each switching sequence duration is labeled ct. This same distance Figure 6C Also marked as ct in Figure 6B and Figure 6C There are 12 sample regions distributed on the slow axis within each distance marked ct in . Therefore, the combination of using the signal director 14 to steer the system output signal and reducing the fast axis scan speed can provide the same slow axis resolution as increasing the fast axis scan speed.

[0111] The fast axis scan speed (the speed provided by the beam guide in the fast axis direction) can be represented by the rate of angular change of the system output signal in the fast axis direction away from the direction of travel of the LIDAR system (fast axis angular rate of change). The slow axis scan speed (the speed provided by the beam guide in the slow axis direction) can be represented by the rate of angular change of the system output signal along the slow axis away from the direction of travel of the LIDAR system (slow axis angular rate of change). The slow axis and the fast axis can be perpendicular to each other. In some cases, the ratio of the fast axis angular rate of change: the slow axis angular rate of change 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 fast axis angular rate of change may be greater than 100, 200 or 300 degrees / second and / or less than 500, 1000 or 2000 degrees / second and / or the slow axis angular rate of change may be greater than 20, 50 or 100 degrees / second and / or less than 200, 500 or 1000 degrees / second.

[0112] although Figure 6B and Figure 6C One or more beam directors 78 are shown steer the system output signal back and forth in a zigzag path in the field of view, but one or more beam directors 78 may steer the system output signal back and forth in the field of view using other patterns. For example, the path need not include straight segments connected at sharp angles, but may include straight segments connected by curves. Alternatively, the path may include curves and / or curved segments and may not include straight segments. For example, the path may be configured as a series of s-shaped sections.

[0113] FIG. 6A to FIG. 6C The field of view of a LIDAR system with a single core is shown. When the LIDAR system has multiple cores, the fields of view of different cores can be stitched together to form the field of view of the LIDAR system.

[0114] Suitable platforms for LIDAR chips include, but are not limited to, silicon dioxide, indium phosphide, and silicon-on-insulator wafers. Figure 7 is a cross-section of a silicon-on-insulator wafer. A silicon-on-insulator (SOI) wafer includes a buried layer 300 between a substrate 302 and an optical transmission medium 304. In a silicon-on-insulator wafer, the buried layer 300 is silicon dioxide, while the substrate 302 and the optical transmission medium 304 are silicon. The substrate of an optical platform such as an SOI wafer can serve as a base for a LIDAR chip. For example, in some cases, Figure 1 The optical components shown in can be positioned on or over the top and / or sides of the same substrate.

[0115] Figure 7The portion of the LIDAR chip shown in FIG. 1 includes a waveguide structure suitable for use with a chip constructed from a silicon-on-insulator wafer. A ridge 306 of the optical transmission medium 304 extends away from a slab region 308 of the optical transmission medium 304. The optical signal is confined between the top of the ridge and the buried layer 300. Thus, the ridge 306 at least partially defines a waveguide.

[0116] The size of the ridge waveguide is Figure 7 . For example, the ridge has a width labeled w and a height labeled h. The thickness of the slab region is labeled t. For LIDAR applications, these dimensions may be more important than for other applications because higher levels of optical power need to be used than for other applications. The ridge width (labeled w) is greater than 1 mm and less than 4 mm, the ridge height (labeled h) is greater than 1 mm and less than 4 mm, and the slab region thickness is greater than 0.5 mm and less than 3 mm. These dimensions may apply to straight or substantially straight portions of the waveguide, curved portions of the waveguide, and tapered portions of (one or more) waveguides. Therefore, these portions of the waveguide will be single-mode. However, in some cases, these dimensions apply to straight or substantially straight portions of the waveguide. Additionally or alternatively, the curved portion of the waveguide may have a reduced plate thickness to reduce optical losses in the curved portion of the waveguide. For example, the curved portion of the waveguide may have a ridge extending away from the slab region having a thickness greater than or equal to 0.0 mm and less than 0.5 mm. While the above dimensions will typically provide a straight or substantially straight portion of the waveguide having a single-mode structure, they may result in tapered portion(s) and / or curved portion(s) that are multi-mode. Coupling between a multi-mode geometry and a single-mode geometry may be achieved using a taper that does not substantially excite higher-order modes. Thus, a waveguide may be constructed such that a signal carried in the waveguide is carried in a single mode even when the signal is carried in a portion of the waveguide having multi-mode dimensions. Figure 7 The waveguide structure is suitable for Figure 1 Construct all or part of the waveguide on the LIDAR chip.

[0117] Suitable signal directors 14 for use with the LIDAR chip include, but are not limited to, optical switches such as cascaded Mach-Zehnder interferometers and microring resonator switches. In one example, the signal director 14 comprises a cascaded Mach-Zehnder interferometer using a thermal or free carrier injection phase shifter. Fig. 8A and Figure 8B An example of an optical switch comprising cascaded Mach-Zehnder interferometers 416 is shown. Fig. 8A is a top view of a light switch. Figure 8B It is along Fig. 8A The line marked B in Fig. 8A Cross-section of the optical switch shown in .

[0118] The optical switch receives an outgoing LIDAR signal from the utility waveguide 12. The optical switch is configured to direct the outgoing LIDAR signal to one of the plurality of alternating waveguides 16. The optical switch includes an interconnecting waveguide 414 that connects a plurality of Mach-Zehnder interferometers 416 in a cascade arrangement. Each Mach-Zehnder interferometer 416 directs the outgoing LIDAR signal to one of the two interconnecting waveguides 414. Electronics can operate each Mach-Zehnder to select which of the two interconnecting waveguides 414 receives the outgoing LIDAR signal from the Mach-Zehnder interferometer 416. The interconnecting waveguide 414 that receives the outgoing LIDAR signal can be selected so that the outgoing LIDAR signal is directed to a specific one of the alternating waveguides 16 by the optical switch.

[0119] Each Mach-Zehnder interferometer 416 includes two branch waveguides 418, each branch waveguide 418 receiving a portion of the outgoing LIDAR signal from the utility waveguide 12 or the interconnect waveguide 414. Each Mach-Zehnder interferometer 416 includes a directional component 420 that receives the two portions of the outgoing LIDAR signal from the branch waveguides 418. The directional component 420 steers the outgoing LIDAR signal to one of the two interconnect waveguides 414 configured to receive the outgoing LIDAR signal from the directional component 420. The interconnect waveguide 414 to which the outgoing LIDAR signal is directed varies depending on the phase difference between the two different portions of the outgoing LIDAR signal received by the directional component 420. Although Fig. 8A A directional coupler is shown operating as the directional component 420, but other directional components 420 may be used. Suitable alternative directional components 420 include, but are not limited to, multi-mode interference (MMI) devices and tapered couplers.

[0120] Each Mach-Zehnder interferometer 416 includes a phase shifter 422 positioned along one of the branch waveguides 418. The output component includes a conductor 424 in electrical communication with the phase shifter 422. The conductors 424 are shown as dashed lines so that they can be easily distinguished from underlying features. The conductors 424 each terminate at a contact pad 426. The contact pad 426 can be used to provide electrical communication between the conductor 424 and the electronic device. Therefore, the conductor 424 provides electrical communication between the electronic device and the phase shifter 422, and allows the electronic device 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.

[0121] The electronics may operate each phase shifter 422 to control the phase difference between portions of the outgoing LIDAR signal received by the directional component 420. In one example, the phase shifter 422 may be operated to change the refractive index of a portion of at least a portion of the branch waveguide 418. Changing the refractive index of a portion of the branch waveguide 418 in the Mach-Zehnder interferometer 416 changes the effective length of the branch waveguide 418 and, therefore, changes the phase difference between portions of the outgoing LIDAR signal received by the directional component 420. The ability of the electronics to change the phase difference allows the electronics to select the interconnect waveguide 414 that receives the outgoing LIDAR signal from the directional component 420.

[0122] Figure 8B An example of a suitable configuration of a phase shifter 422 on a branch waveguide 418 is shown. The branch waveguide 418 is at least partially defined by a ridge 306 of the light-transmitting medium 304, the ridge 306 extending away from a slab region 308 of the light-transmitting medium 304. Doped regions 428 extend into the slab region 308, wherein one of the doped regions includes an n-type dopant and one of the doped regions 428 includes a p-type dopant. A first cladding 430 is located between the light-transmitting medium 304 and the conductor 424. The conductors 424 each extend through an opening in the first cladding 430, contacting one of the doped regions 428. A second cladding 432 is optionally located above the first cladding 430 and above the conductor 424. An electronic device may apply a forward bias to the conductor 424 to generate a current through the branch waveguide 418. The resulting carrier injection into the branch waveguide 418 results in free carrier absorption, thereby changing the refractive index in the branch waveguide 418.

[0123] Figure 8B The first cladding 430 and / or the second cladding 432 shown in the figure can each represent one or more layers of material. The materials used for the first cladding 430 and / or the second cladding 432 can be selected to provide electrical isolation of the conductor 424, a lower refractive index relative 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 used for the first cladding 430 and / or the second cladding 432 can be doped or undoped.

[0124] Where the LIDAR system includes multiple cores, the LIDAR system may include multiple signal directors 76, and different signal directors 76 may receive LIDAR output signals from different selections of cores. Fig. 9 Shows Figure 3The LIDAR system is modified to have multiple signal directors 76, each signal director receiving the LIDAR output signal from a different one of the cores.

[0125] Figure 1 Each core is shown to include a different light source 10. However, multiple cores, all cores, or a portion of the cores may receive outgoing LIDAR signals from a common light source. In some cases, the cores are arranged in groups, where each core in a group receives outgoing LIDAR signals from the same common light source, and cores in different groups receive outgoing LIDAR signals from different common light sources. In some cases, a group of cores may include a single core. For example, Fig.10 Shows Figure 3 A LIDAR system in which the light source 10 is located outside the core and each core receives an outgoing LIDAR signal from the light source. The light source 10 may be arranged in accordance with Figure 2 The method is constructed in a manner disclosed in the context of.

[0126] The first optical link 440 provides optical communication between the light source 10 and the signal separator 442. The second optical link 444 provides optical communication between the signal separator 442 and the utility waveguide 12 on different cores 4. The light source 10 outputs a preliminary signal received on the first optical link 440. The signal separator 442 receives the preliminary signal from the first optical link 440. The signal separator 442 divides the preliminary signal into a plurality of branch signals, each of which is received on a different one of the second optical links 444. Each utility waveguide 12 receives a branch signal from a different one of the optical links 444. The branch signal portion entering the utility waveguide serves as an outgoing LIDAR signal.

[0127] The LIDAR system may optionally include an amplifier 446 positioned along the first optical link 440 to amplify the power of the preliminary signal. Suitable amplifiers 446 for use along the optical link include, but are not limited to, SOAs, erbium doped fiber amplifiers (EDFAs), and praseodymium doped fiber amplifiers (PDFAs).

[0128] When it is desired that different outgoing LIDAR signals have the same or substantially the same wavelength distribution, suitable signal separators 442 include, but are not limited to, wavelength-independent signal combiners, such as optical couplers, y-junctions, MMIs, cascaded attenuated optical couplers, and cascaded y-junctions. When it is desired that different outgoing LIDAR signals have different wavelength distributions, suitable signal separators 442 include, but are not limited to, wavelength-dependent signal separators 442, including optical demultiplexers, such as arrayed waveguide gratings (AWGs) and trapezoidal gratings.

[0129] In some cases where multiple different cores receive outgoing LIDAR signals from a common light source, only one core that receives its outgoing LIDAR signal from the common light source includes a control branch. Therefore, other cores that receive outgoing LIDAR signals from the same common light source may not include a control branch. Figure 1 The directional coupler 66, control waveguide 68 and control component 70 are shown in FIG.

[0130] from Figure 1 As is apparent from FIG. 4 , the LIDAR system may optionally include one or more optical signal amplifiers 446. For example, the amplifiers 446 may optionally be positioned along a utility waveguide, such as Figure 1 In another example, the amplifier 446 is optionally positioned along all or a portion of the alternating waveguide 16, such as Figure 1 B. The electronics may operate amplifiers 446 to amplify the power of the outgoing LIDAR signal, thereby amplifying the power of the system output signal. The electronics may operate each amplifier 446 to amplify the power of the outgoing LIDAR signal. Suitable amplifiers 446 for use on the LIDAR chip include, but are not limited to, semiconductor optical amplifiers (SOAs).

[0131] Figure 1 The amplifier 446 shown in FIG. 1 is respectively located before one of the splitters 24. In some cases, this location of the amplifier 446 may cause saturation of one or more components selected from the group consisting of the first auxiliary light sensor 218, the second auxiliary light sensor 220, the first light sensor 223, and the second light sensor 224. For example, the amplifier 446 may increase the power level of the reference signal to a level at which saturation occurs. A beam dump may be used to reduce the power level of the reference signal to a level at which saturation is reduced or eliminated.

[0132] from Figure 5B It will be apparent that the LIDAR system may optionally include one or more electrical signal amplifiers 447. Each amplifier 447 is positioned to provide amplification of a first data signal traveling between a first light sensor (e.g., first balanced detector 225) and an analog-to-digital converter, or a second data signal traveling between a second light sensor (e.g., second balanced detector 226) and an analog-to-digital converter. Figure 3 D shows each electrical signal amplifier 447 positioned along the first data line 228 or the second data line 232, but the electrical signal amplifier 447 may be positioned along the common data line 273 or the second common data line 275. Figure 3E shows each electric signal amplifier 447 located along the common data line 273 or the second common data line 275, but the electric signal amplifier 447 may be located along the first data line 228 or the second data line 232. Suitable electric signal amplifiers 447 include, but are not limited to, transimpedance amplifiers (TIA).

[0133] Fig.11 A portion of a LIDAR chip is shown that includes a beam dump 72 that is configured to scatter coupled portions of the outgoing LIDAR signal without reflecting a significant amount of the coupled portions of the outgoing LIDAR signal back into the alternating 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, with a depth such that the collected signal is incident on one or more sides of the recess 454. The recess 454 can be shaped to cause the collected signal to be scattered. For example, the recess 454 can have a star shape, or can include any number of irregularly positioned sides. In some cases, the recess 454 can extend through the optical transmission medium to an underlying layer, such as a buried layer of the silicon-on-insulator wafer.

[0134] The optical sensor that interfaces with the waveguide on the LIDAR chip can be a component that is separated from the chip and then 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 manufactured by Hamamatsu located in Hamamatsu City, Japan or InGaAs APDs (avalanche photodiodes) manufactured by Hamamatsu located in Hamamatsu City, Japan. These optical sensors can be located in the center of the LIDAR chip. Alternatively, all or part of the waveguides that terminate at the optical sensor can terminate at a small facet located at the edge of the chip, and the optical sensor can be attached to the edge of the chip above the small facet so that the optical sensor receives light transmitted through the small facet. The use of an optical sensor as a component separate from the chip is applicable to all or part of the optical sensors selected from the group consisting of a first optical sensor and a second optical sensor.

[0135] As an alternative to the light sensors being separate components, all or part of the light sensors may be integrated with the chip. For example, examples of light sensors interfaced with ridge waveguides on a chip comprised of a silicon-on-insulator wafer may be found in: Optics Express Vol. 15, No. 21, 13965-13971 (2007); U.S. Pat. No. 8,093,080, issued on January 10, 2012; U.S. Pat. No. 8,242,432, issued on August 14, 2012; and U.S. Pat. No. 6,108,472, issued on August 22, 2000, each of which is incorporated herein in its entirety. The use of light sensors integrated with the chip is applicable to all or part of the light sensors selected from the group consisting of a first light sensor and a second light sensor.

[0136] Suitable electronics 62 for use in a LIDAR system may include, but are not limited to, a controller comprising or consisting of analog circuits, digital circuits, processors, microprocessors, digital signal processors (DSPs), application specific integrated circuits (ASICs), computers, microcomputers, or combinations thereof suitable for performing the above-described operations, monitoring, and control functions. In some cases, the controller may access a memory that includes instructions for the controller to execute during the execution of the operations, control, and monitoring functions. Although the electronics are shown as a single component in a single location, the electronics may include multiple different components that are independent of each other and / or placed in different locations. In addition, as described above, all or part of the disclosed electronics may be included on a chip, including electronics integrated with a chip.

[0137] The components on the LIDAR chip can be fully or partially integrated with the LIDAR chip. For example, the integrated optical component may include or consist of a portion of the wafer from which the LIDAR chip is manufactured. The wafer that can serve as a platform for the LIDAR chip may include multiple layers of material. At least a portion of the different layers may be different materials. For example, a silicon-on-insulator wafer includes a buried layer 300 between a substrate 302 and an optical transmission medium 304, as shown in FIG4 . The integrated on-chip components may be formed by using etching and masking techniques to define the features of the components in the optical transmission medium 304. For example, a plate 318 defining a waveguide and a stopper recess may be formed in a desired area of ​​the wafer using different etchings of the wafer. Thus, the LIDAR chip includes a portion of the wafer, and the integrated on-chip components may each include or consist of a portion of the wafer. In addition, the integrated on-chip components may be configured so that the optical signal traveling through the component travels through one or more layers originally included in the wafer. For example, the waveguide of FIG4 guides the optical signal through the optical transmission medium 304 in the wafer. The integrated components may optionally include materials other than those present on the wafer. For example, the integrated components may include reflective materials and / or cladding.

[0138] Numeric labels (e.g., first, second, third, etc.) are used to distinguish different features and components, and do not indicate the order or presence of lower numbered features. For example, the second component may be present without the first component and / or the third step may be performed before the first step. The optical signals disclosed above each include, consist of, or consist essentially of light from the previous optical signal(s) from which the optical signal was derived. For example, the incoming LIDAR signal includes, consists of, or consists essentially of light from the LIDAR input signal.

[0139] Although the LIDAR system is disclosed to use a complex signal such as a complex data signal, the LIDAR system may also use a real signal. Thus, the mathematical transformation may be a real transformation, and components associated with the generation and use of orthogonal components may be removed from the LIDAR system. Thus, the LIDAR system may use a single signal combiner. Additionally or alternatively, a single light sensor may replace each balanced detector.

[0140] In view of these teachings, those skilled in the art will readily recognize other embodiments, combinations and modifications of the present invention. Therefore, the present invention is limited only by the appended claims, which include all such embodiments and modifications when viewed in conjunction with the above description and drawings.

Claims

1. An imaging system, comprising: A LIDAR system comprising a signal director capable of directing an outgoing LIDAR signal to any one of a plurality of different alternating waveguides, each of the alternating waveguides is associated with a different switching channel, wherein an optical signal including light from the outgoing LIDAR signal directed to a particular one of the alternating waveguides can be characterized as carrying the switching channel associated with that alternating waveguide; the LIDAR system being configured to output a system output signal comprising light from the outgoing LIDAR signal, The system output signal carries different switching channels; The LIDAR system is configured to receive a system return signal including light from one of the system output signals after an object located external to the system has received and reflected the system output signal; The LIDAR system includes a signal combiner that generates different composite signals by combining light from system return signals carrying different switching channels with a reference signal; electronics that calculate LIDAR data based on the frequency of one or more of the composite signals, the LIDAR data indicating radial velocity and / or distance between the LIDAR system and one or more objects external to the LIDAR system; and The LIDAR system is configured to continue generating a composite signal carrying a first of the switched channels for a period of time after the imaging system has ceased outputting a system output signal carrying the first switched channel.

2. The imaging system according to claim 1, wherein: The LIDAR system can direct the outgoing LIDAR signal to a different one of the alternating waveguides while still generating LIDAR data according to the frequency of the composite signal carrying the first switching channel.

3. The imaging system according to claim 1, wherein: The outgoing LIDAR signal carries multiple different wavelength channels.

4. The imaging system according to claim 1, wherein: The system output signal carries 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 rates and / or in different directions.

6. The imaging system according to claim 4, wherein: There is no frequency overlap between different wavelength channels.

7. The imaging system according to claim 4, wherein: Each wavelength channel in the system output signal is simultaneously incident on the same sample area in the field of view.

8. The imaging system of claim 1, wherein: The signal combiner is one of a plurality of signal combiners included in the LIDAR system, Each of the signal combiners generates a composite signal, and The composite signals generated by different signal combiners carry different ones of the wavelength channels.

9. The imaging system of claim 8, wherein: The electronics uses the beat frequency of the composite signal carrying the different wavelength channels to calculate LIDAR data for the sample area.

10. The imaging system of claim 1, wherein: The direction in which the system output signal travels away from the imaging system changes in response to operating the signal director, thereby changing the alternate waveguide that receives the outgoing LIDAR signal.

11. The imaging system according to claim 10, wherein: A beam director is configured to steer the system output signal in a field of view, the path of the system output signal in the field of view has contributions from the beam director and also from the signal director, The beam guide contributes to the path by which the system output signal moves back and forth across the field of view in a two-dimensional path, and The signal director's contribution to the path is a shift of the system output signal transverse to the two-dimensional path contribution provided by the beam director.

12. The system according to claim 11, wherein: The beam director is a steerable plane mirror.

13. The system according to claim 12, wherein: The beam guide is configured to scan the system output signal in both a slow axis and a fast axis simultaneously, The beam guide scans the system output signal on a slow axis so that the direction in which the system output signal travels away from the LIDAR system changes at a slow angular rate, The beam director scans the system output signal in a fast axis so that the direction of the system output signal traveling away from the LIDAR system changes at a fast angular rate, A ratio of the fast angular rate to the slow angular rate is greater than 2:1 and less than 200:

1.

14. The system according to claim 13, wherein: The beam guide's contribution to the path is that the system output signal moves in a zigzag pattern.

Images