Lidar system with reduced speckle sensitivity

Abstract

A plurality of LIDAR output signals are generated and directed simultaneously toward the same sample region in the field of view. The LIDAR output signals have one or more optical diversities selected from the group consisting of wavelength diversity, polarization diversity, and diversity in the angle of incidence of the LIDAR output signals with respect to the sample region.

Description

[0001] Related applications

[0002] This application claims the benefit of U.S. Provisional Patent Application Serial No. 62 / 803,459 entitled “LIDAR System with Reduced SpeckleSensitivity”, filed February 9, 2019, and is incorporated herein in its entirety. Technical Field

[0003] This invention relates to optical devices. In particular, this invention relates to LIDAR systems. Background Technology

[0004] Speckle is a phenomenon that can affect the performance of a LiDAR system, which outputs a coherent LiDAR signal reflected from a diffuse surface. Since the surface of the object reflecting the signal in a LiDAR system is typically a diffuse or semi-diffuse surface, most of the LiDAR output signal reflected by the object is not specularly reflected as would occur from a mirror surface. Instead, it is scattered in multiple directions, resulting in a LiDAR input signal with multiple wavefronts.

[0005] The coherent nature of the LIDAR input signal leads to interference between multiple wavefronts, resulting in phase and intensity variations. These variations can be the source of bright and dark spots in far-field images, hence the term "speckle pattern." For LIDAR applications, these variations can be detrimental to performance because they can cause a variable number of optical couplings back to the LIDAR chip, and thus cause signal "attenuation" under certain conditions. For a given LIDAR output signal at a given wavelength, these conditions will vary with surface properties, the angle of incidence of the LIDAR output signal on the reflecting object, the polarization of the LIDAR output signal, the distance between the reflecting object and the LIDAR output signal source, and the path length introduced by the atmosphere (such as that caused by changes in air density) as the LIDAR output signal travels between the reflecting object and the LIDAR output signal source.

[0006] Due to the nature of diffuse reflectors, the speckle effect will vary with the position of the beam on the surface. As a result, rapid movement of the reflecting object can cause signal attenuation during the measurement period. Because it is an interference effect, the speckle pattern for a given position of the reflecting object and atmospheric conditions will vary with the wavelength and polarization of the LiDAR output signal, as well as the distance between the LiDAR output signal source and the reflecting object.

[0007] Signal attenuation due to speckle limits the performance of LIDAR systems, as it can lead to increased measurement inaccuracies and even prevent measurements from being taken at a given point. Consequently, there is a need for improved coherent LIDAR systems with reduced sensitivity to speckle. Summary of the Invention

[0008] A LIDAR system includes one or more LIDAR chips that generate multiple LIDAR output signals. The system further includes electronics that operate the one or more LIDAR chips such that the LIDAR output signals are simultaneously directed to the same sample region in the field of view. The LIDAR output signals have one or more optical diversity features selected from a group consisting of wavelength diversity, polarization diversity, and incident angle diversity of the LIDAR output signals in the sample region.

[0009] Operating a LIDAR system involves generating multiple LIDAR output signals. These LIDAR output signals are simultaneously directed to the same sample region within the field of view, such that the LIDAR output signals possess one or more optical diversity features selected from a group consisting of wavelength diversity, polarization diversity, and the incident angle diversity of the LIDAR output signals in the sample region. Attached Figure Description

[0010] Figure 1 This is a top view of a LiDAR chip.

[0011] Figure 2 It is based on the construction of silicon wafers on insulators. Figure 1 A cross-section of a portion of a LiDAR chip.

[0012] Figure 3A This is a schematic diagram of the LIDAR system.

[0013] Figure 3B This is a schematic diagram of another embodiment of the LIDAR system.

[0014] Figure 4 This is a schematic diagram of another embodiment of the LIDAR system.

[0015] Figure 5 This is a schematic diagram of another embodiment of the LIDAR system.

[0016] Figure 6 The illustration shows multiple light sources configured to generate outgoing optical signals including multiple channels.

[0017] Figure 7 The illustration shows a light source that includes multiple laser sources.

[0018] Figure 8 The illustration shows an example of a structure configured to generate an optical signal comprising multiple channels.

[0019] Figure 9A An example of a processing unit is illustrated.

[0020] Figure 9B Provided applicable to and according to Figure 9A A schematic diagram of the electronic devices used in the constructed processing unit.

[0021] Figure 9C An example of an output component including beam manipulation capabilities is illustrated.

[0022] Figure 10 The configuration of a composite LiDAR chip configured to generate multiple LiDAR output signals is presented.

[0023] Figure 11 The configuration of a composite LiDAR chip is presented, which has multiple LiDAR chips on a common substrate.

[0024] Figure 12 The illustration shows multiple LIDAR chips, each outputting a different LIDAR output signal, and each LIDAR output signal is incident on the same sample area in the field of view.

[0025] Figure 13 The illustration shows a single LIDAR chip, each LIDAR chip outputs multiple LIDAR output signals, and each LIDAR output signal is incident on the same sample area in the field of view.

[0026] Figure 14 The diagram shows a LIDAR chip that outputs multiple LIDAR output signals, each of which is incident on the same sample area in the field of view and is at a different wavelength.

[0027] Figure 15 The diagram shows a LIDAR chip that outputs multiple LIDAR output signals, each of which is incident on the same sample area in the field of view and is at a different wavelength. Detailed Implementation

[0028] Multiple LiDAR output signals are generated and simultaneously directed to the same sample region in the field of view. The LiDAR output signals have one or more optical diversity features selected from a group consisting of wavelength diversity, polarization diversity, and the incident angle diversity of the LiDAR output signal relative to the sample region or an object within the sample region. Different LiDAR output signals directed to the sample region can each be used to generate different LiDAR data results (distance and / or radial velocity between the LiDAR output signal source and the reflecting object) for the sample region. As a result, each sample region can have multiple different LiDAR data results, each associated with a different LiDAR output signal directed toward the sample region. Because each LiDAR output signal directed to the sample region has different optical characteristics, the chance of reducing the effects of speckle to an acceptable level or eliminating them from at least one LiDAR data result increases. Consequently, the different LiDAR data results for the sample region are processed to reduce the effects of speckle. For example, the different LiDAR data results can be averaged to generate synthetic LiDAR data for the sample region. Alternatively, the LiDAR data result most likely to reduce the effects from speckle can be identified and used as the synthetic LiDAR data. For example, when the LIDAR output signal is reflected by a reflective object, a LIDAR input signal is generated and received by the LIDAR chip. The LIDAR input signal received by the LIDAR chip with the highest power level can be identified, and the associated LIDAR data results can be used as synthetic LIDAR data. As a result, the LIDAR system can reduce or even eliminate speckle effects from the LIDAR data.

[0029] Figure 1 This is a top view of a LIDAR chip. The illustrated LIDAR chip includes a photonic integrated circuit (PIC) and may be a photonic integrated circuit chip. The LIDAR chip includes a laser cavity. The laser cavity includes a light source 10, which may include or be composed of a gain medium (not shown) for a laser. The LIDAR chip also includes a cavity waveguide 12 that receives optical signals from the light source 10. The light source may be positioned in a recess 13 such that the facets of the light source are optically aligned with the facets of the cavity waveguide 12 to allow the light source and the cavity waveguide 12 to exchange optical signals. The cavity waveguide 12 carries the optical signals to a partial return device 14. The illustrated partial return device 14 is a grating, such as a Bragg grating. However, other partial return devices 14 may be used; for example, a mirror may be used in conjunction with an echelle grating and an arrayed waveguide grating.

[0030] Partial return device 14 returns a portion of the optical signal as a return signal to cavity waveguide 12. For example, cavity waveguide 12 returns the return signal to light source 10, such that the returned portion of the optical signal travels through the gain medium. Light source 10 is configured such that at least a portion of the return signal is added to the optical signal received at cavity waveguide 12. For example, light source 10 may include highly reflective, fully reflective, or partially reflective devices 15 that reflect the return signal received from the gain medium back into the gain medium. As a result, light can resonate between partial return device 14 and reflective device 15, thereby forming a distributed Bragg reflector (DBR) laser cavity. Compared to DFB lasers, DBR laser cavities have inherently narrow linewidths and longer coherence lengths, and therefore improve performance when objects reflecting the LIDAR output signal from the LIDAR chip are located further away from the LIDAR system.

[0031] Partial return device 14 transmits a portion of the optical signal received from cavity waveguide 12 to a utility waveguide 16 included on the LIDAR chip. A portion of the optical signal received from partial return device 14 by utility waveguide 16 serves as the output of the laser cavity. The output of the laser cavity serves as the outgoing LIDAR signal on utility waveguide 16. Utility waveguide 16 terminates at facet 18 and carries the outgoing LIDAR signal to facet 18. Facet 18 can be positioned such that the outgoing LIDAR signal traveling through facet 18 leaves the LIDAR chip and serves as the LIDAR output signal. For example, facet 18 can be positioned at the edge of the LIDAR chip, so that the outgoing LIDAR signal traveling through facet 18 leaves the LIDAR chip and serves as the LIDAR output signal.

[0032] The LIDAR output signal travels away from the LIDAR chip and is reflected by objects in the LIDAR signal path. The reflected signal travels away from the object. At least a portion of the reflected signal returns to facet 18 of the practical waveguide 16. Therefore, a portion of the reflected signal can enter the practical waveguide 16 through facet 18 and serve as the LIDAR input signal guided by the practical waveguide 16.

[0033] The utility waveguide 16 may optionally include a tapered portion prior to facet 18. For example, the utility waveguide 16 may include a tapered section 20 terminating at facet 18. Taper 20 can relax the alignment tolerances required for efficient coupling of the utility waveguide 16 to the LIDAR input light and the output LIDAR signal. Therefore, taper 20 can increase the percentage of LIDAR input signals successfully returned to the LIDAR chip for processing. In some cases, taper 20 is configured such that facet 18 has an area two, five, or ten times larger than the cross-sectional area of ​​the straight portion of the utility waveguide 16. Although Figure 1Cone 20 is shown as a horizontal cone, but cone 20 can be a horizontal and / or vertical cone. Horizontal and / or vertical cones can be linear and / or curved. In some cases, cone 20 is an adiabatic cone.

[0034] The LIDAR chip includes a data branch 24 in which an optical signal carrying LIDAR data is generated. The data branch includes an optical coupler 26 that moves a portion of the optical signal from the practical waveguide 16 into the data branch. For example, the optical coupler 26 couples a portion of the outgoing LIDAR signal from the practical waveguide 16 to a reference waveguide 27 as a reference signal. The reference waveguide 27 carries the reference signal to the optical combination component 28.

[0035] Optical coupler 26 also couples a portion of the LIDAR input signal from practical waveguide 16 to comparison waveguide 30. This portion of the LIDAR input signal coupled to comparison waveguide 30 serves as a comparison signal. The comparison signal includes at least a portion of the light from the LIDAR input signal. The comparison signal can exclude light from the reference optical signal. Comparison waveguide 30 carries the comparison signal to optical combination component 28.

[0036] The illustrated optical coupler 26 is a result of positioning the utility waveguide 16 sufficiently close to the reference waveguide 27 and the comparison waveguide 30, such that light from the utility waveguide 16 is coupled into the reference waveguide 27 and the comparison waveguide 30; however, other signal tapping components can be used to move a portion of the optical signal from the utility waveguide 16 onto the reference waveguide 27 and the comparison waveguide 30. Examples of suitable signal tapping components include, but are not limited to, Y-junctions, multimode interference couplers (MMIs), and integrated optical circulators.

[0037] The optical combining component 28 combines the comparison signal and the reference signal into a composite signal. The reference signal includes light from the output LIDAR signal. For example, the reference signal can act as a sample of the output LIDAR signal. The reference signal can exclude light from both the LIDAR output signal and the LIDAR input signal. In contrast, the comparison signal light includes light from the LIDAR input signal. For example, the comparison signal can act as a sample of the LIDAR input signal. Therefore, the comparison signal has been reflected by an object located outside the LIDAR chip, while the LIDAR output signal has not yet been reflected by an object located outside the LIDAR chip. When the LIDAR chip and the reflecting object are moving relative to each other, the comparison signal and the reference signal have different frequencies due to the Doppler effect. As a result, a beat occurs between the comparison signal and the reference signal.

[0038] The optical combination component 28 further separates the resulting composite sample signal onto a first detector waveguide 36 and a second detector waveguide 38. The first detector waveguide 36 carries a first portion of the composite sample signal to a first optical sensor 40, which converts the first portion of the composite sample signal into a first electrical signal. The second detector waveguide 38 carries a second portion of the composite sample signal to a second optical sensor 42, which converts the second portion of the composite sample signal into a second electrical signal. Examples of suitable optical sensors include germanium photodiodes (PDs) and avalanche photodiodes (APDs).

[0039] The optical combination component 28, the first optical sensor 40, and the second optical sensor 42 can be connected as a balanced photodetector outputting an electrical data signal. For example, the optical combination component 28, the first optical sensor 40, and the second optical sensor 42 can be connected such that the DC component of the signal photocurrent cancels out, thereby improving detection sensitivity. A suitable method for connecting the first optical sensor 40 and the second optical sensor 42 as a balanced photodetector includes connecting them in series. In one example, both the first optical sensor 40 and the second optical sensor 42 are avalanche photodiodes connected in series. Balanced photodetection is desirable for detecting small signal fluctuations.

[0040] Examples of suitable optical combination components 28 are multimode interference (MMI) devices, such as 2x2 MMI devices. Other suitable optical combination components 28 include, but are not limited to, thermally insulating splitters and directional couplers. In some cases, the function of the illustrated optical combination component 28 is performed by more than one optical component or a combination of optical components.

[0041] A single optical sensor can replace the first optical sensor 40 and the second optical sensor 42, and can output a data signal. When a single optical sensor replaces the first optical sensor 40 and the second optical sensor 42, the optical combination component 28 does not need to include a beam splitting function. As a result, the illustrated optical combination component 28 can be a 2x1 optical combination component, rather than the illustrated 2x1 optical combination component. For example, the illustrated optical combination component can be a 2x1 MMI device. In these cases, the LIDAR chip includes a single detector waveguide that carries the composite sample signal to the optical sensor.

[0042] The data branch includes a data optical attenuator 44 positioned along the comparison waveguide 30, such that the data optical attenuator 44 can be operated to attenuate the comparison signal on the comparison waveguide 30. The LIDAR chip also includes an output optical attenuator 46 positioned along the utility waveguide 16, such that the output optical attenuator 46 can be operated to attenuate the outgoing LIDAR signal on the utility waveguide 16. Suitable attenuators for the data optical attenuator 44 and / or the output optical attenuator 46 are configured to attenuate the intensity of the optical signal. Examples of suitable attenuators configured to attenuate the intensity of the optical signal include carrier injection-based PIN diodes, electroabsorption modulators, and Mach-Zehnder (MZ) modulators.

[0043] The LIDAR chip also includes a sampling directional coupler 50, which couples a portion of the comparison signal from the comparison waveguide 30 to the sampling waveguide 52. The coupled portion of the comparison signal acts as the sampling signal. The sampling waveguide 52 carries the sampling signal to the sampling optical sensor 54. Although... Figure 1 The illustration shows a sampling directional coupler 50 moving a portion of the comparison signal onto the sampling waveguide 52. However, other signal tapping devices can also be used to move a portion of the comparison signal from the comparison waveguide 30 onto the sampling waveguide 52. Examples of suitable signal tapping devices include, but are not limited to, Y-junctions and MMIs.

[0044] The LIDAR chip includes a control branch 55 for controlling the operation of the laser cavity. The control branch includes a directional coupler 56 that moves a portion of the outgoing LIDAR signal from the utility waveguide 16 onto a control waveguide 57. This coupled portion of the outgoing LIDAR signal acts as a tap signal. Although... Figure 1 The illustration shows directional coupler 56 moving a portion of the outgoing LiDAR signal onto control waveguide 57, but other signal tapping devices can also be used to move a portion of the outgoing LiDAR signal from utility waveguide 16 onto control waveguide 57. Examples of suitable signal tapping devices include, but are not limited to, Y-junctions and MMIs.

[0045] The control waveguide 57 carries the tapped signal to the interferometer 58, which separates the tapped signal and then reassembles the different parts of the tapped signal using the phase difference between them. The interferometer 58 shown is a Mach-Zehnder interferometer; however, other interferometers can be used.

[0046] Interferometer 58 outputs a control optical signal on interferometer waveguide 60. Interferometer waveguide 60 carries the control optical signal to control optical sensor 61, which converts the control optical signal into an electrical signal that serves as the electrical control signal. The intensity of the interferometer signal is a function of the frequency and / or frequency change of the output LIDAR signal. For example, a Mach-Zehnder interferometer will output a sinusoidal control optical signal with a fringe pattern. A change in the frequency of the output LIDAR signal will cause a change in the frequency of the control optical signal. Therefore, the frequency of the electrical control signal output from control optical sensor 61 is a function of the frequency of the output LIDAR signal. Other detection mechanisms can be used to replace control optical sensor 61. For example, control optical sensor 61 can be replaced by a balanced photodetector arranged as optical combination component 28, first optical sensor 40, and second optical sensor 42.

[0047] Electronic device 62 can operate one or more components on the LIDAR chip. For example, electronic device 62 can electrically communicate with and control the operation of the light source 10, data optical attenuator 44, output optical attenuator 46, first optical sensor 40, second optical sensor 42, sampling optical sensor 54, and control optical sensor 61. Although electronic device 62 is shown outside the LIDAR chip, all or part of the electronic device may be included on the LIDAR chip. For example, the LIDAR chip may include an electrical conductor connecting the first optical sensor 40 and the second optical sensor 42 in series.

[0048] During LIDAR chip operation, electronics 62 operates light source 10, causing the laser cavity to output an outgoing LIDAR signal. Electronics 62 then operates the LIDAR chip through a series of loops, where each loop generates LIDAR data for a sample region in the field of view. During each loop, the data signal is sampled multiple times. During each sampling period, the electronics adjust the frequency of the outgoing LIDAR signal. As will be described in more detail below, the electronics may use an output from a control branch to control the frequency of the outgoing LIDAR signal such that the frequency of the outgoing LIDAR signal as a function of time is known to the electronics. In some cases, the loop includes at least a first sampling and a second sampling. During the first sampling period, electronics 62 may increase the frequency of the outgoing LIDAR signal, and during the second sampling period, electronics 62 may decrease the frequency of the outgoing LIDAR signal. For example, the laser cavity may be configured to output an outgoing LIDAR signal (and a corresponding LIDAR output signal) with a wavelength of 1550 nm. During the first sampling period, the electronic device 62 can increase the frequency of the emitted LIDAR signal (and the corresponding LIDAR output signal) so that the wavelength decreases from 1550 nm to 1459.98 nm, and then decrease the frequency of the emitted LIDAR signal so that the wavelength increases from 1459.98 nm to 1550 nm.

[0049] As the frequency of the outgoing LIDAR signal increases during the first sampling period, the LIDAR output signal travels away from the LIDAR chip and then returns to the LIDAR chip as the LIDAR input signal. A portion of the LIDAR input signal becomes the comparison signal. During the time that the LIDAR output signal and the LIDAR input signal are traveling between the LIDAR chip and the reflective object, the frequency of the outgoing LIDAR signal continues to increase. Since a portion of the outgoing LIDAR signal becomes the reference signal, the frequency of the reference signal continues to increase. As a result, the comparison signal enters the optical assembly at a lower frequency than the reference signal that simultaneously enters the optical assembly. Additionally, the farther the reflective object is positioned from the LIDAR chip, the more the frequency of the reference signal increases before the LIDAR input signal returns to the LIDAR chip. Therefore, the greater the difference between the frequency of the comparison signal and the frequency of the reference signal, the farther the reflective object is from the LIDAR chip. Consequently, the difference between the frequency of the comparison signal and the frequency of the reference signal is a function of the distance between the LIDAR chip and the reflective object.

[0050] For the same reason, when the frequency of the emitted LIDAR signal decreases during the second sampling period, the comparison signal enters the optical assembly at a higher frequency than the reference signal that enters the optical assembly at the same time, and the difference between the frequency of the comparison signal and the frequency of the reference signal during the second sampling period is also a function of the distance between the LIDAR chip and the reflecting object.

[0051] In some cases, the difference between the frequency of the comparison signal and the frequency of the reference signal can also be a function of the Doppler effect. This is because the relative movement of the LiDAR chip and the reflecting object can affect the frequency of the comparison signal. For example, when the LiDAR chip is moving toward or away from the reflecting object and / or the reflecting object is moving toward or away from the LiDAR chip, the Doppler effect may affect the frequency of the comparison signal. Since the frequency of the comparison signal is a function of the speed at which the reflecting object is moving toward or away from the LiDAR chip and / or the speed at which the LiDAR chip is moving toward or away from the reflecting object, the difference between the frequency of the comparison signal and the frequency of the reference signal is also a function of the speed at which the reflecting object is moving toward or away from the LiDAR chip and / or the speed at which the LiDAR chip is moving toward or away from the reflecting object. Therefore, the difference between the frequency of the comparison signal and the frequency of the reference signal is a function of the distance between the LiDAR chip and the reflecting object, and also a function of the Doppler effect.

[0052] The composite sample signal and the data signal each effectively compare the comparison signal and the reference signal. For example, since the optical combining component combines the comparison signal and the reference signal, and these signals have different frequencies, there is a beat between the comparison signal and the reference signal. Therefore, the composite sample signal and the data signal have beat frequencies related to the frequency difference between the comparison signal and the reference signal, and the beat frequency can be used to determine the frequency difference between the comparison signal and the reference signal. A higher beat frequency in the composite sample signal and / or the data signal indicates a higher difference between the frequencies of the comparison signal and the reference signal. As a result, the beat frequency of the data signal is a function of the distance between the LIDAR chip and the reflecting object, and also a function of the Doppler effect.

[0053] As noted above, the beat frequency is a function of two unknowns: the distance between the LIDAR chip and the reflecting object, and the relative velocity between the LIDAR chip and the reflecting object (i.e., the contribution of the Doppler effect). The change in the frequency difference between the compared signal and the reference signal ( )Depend on Given, where f is the frequency of the LIDAR output signal, and is therefore the reference signal, Let be the relative velocity between the LIDAR chip and the reflecting object, and c be the speed of light in air. The use of multiple different samples allows the electronics 62 to solve for both unknowns. For example, the beat frequency determined for the first sample is related to the unknown distance and the Doppler contribution, and the beat frequency determined for the second sample is also related to the unknown distance and the Doppler contribution. The availability of these two relationships allows the electronics 62 to solve for both unknowns. Therefore, the distance between the LIDAR chip and the reflecting object can be determined without being affected by the Doppler effect. Furthermore, in some cases, the electronics 62 uses this distance in conjunction with the Doppler effect to determine the velocity of the reflecting object toward or away from the LIDAR chip.

[0054] When the relative velocity between the target and the source is zero or very small, the Doppler effect contributes essentially nothing to the beat frequency. In these cases, the Doppler effect makes no substantial contribution to the beat frequency, and the electronics 62 can determine the distance between the LIDAR chip and the reflecting object using only the first sample.

[0055] During operation, the electronics 62 can adjust the frequency of the emitted LIDAR signal in response to an electrical control signal output from the control light sensor 61. As noted above, the amplitude of the electrical control signal output from the control light sensor 61 is a function of the frequency of the emitted LIDAR signal. Therefore, the electronics 62 can adjust the frequency of the emitted LIDAR signal in response to the amplitude of the control. For example, when changing the frequency of the emitted LIDAR signal during one of the sampling periods, the electronics 62 can have a suitable range of values ​​for the amplitude of the electrical control signal as a function of time. At multiple different times during the sampling period, the electronics 62 can compare the amplitude of the electrical control signal with a range of values ​​in the sample associated with the current time. If the amplitude of the electrical control signal indicates that the frequency of the emitted LIDAR signal is outside the associated range of the electrical control signal amplitude, the electronics 62 can operate the light source 10 to change the frequency of the emitted LIDAR signal, thus bringing it into the associated range. If the amplitude of the electrical control signal indicates that the frequency of the emitted LIDAR signal is within the associated range of the electrical control signal amplitude, the electronics 62 does not change the frequency of the emitted LIDAR signal.

[0056] During operation, the electronics 62 can adjust the attenuation level provided by the output optical attenuator 46 in response to the sampled signal from the sampled light sensor 54. For example, the electronics 62 can operate the output optical attenuator 46 to increase the attenuation level in response to the amplitude of the sampled signal being higher than a first signal threshold, and / or to reduce the magnitude of the power drop in response to the amplitude of the sampled signal being lower than a second signal threshold.

[0057] In some cases, the electronics 62 adjusts the attenuation level provided by the output optical attenuator 46 to prevent or reduce the impact of back reflection on the laser cavity performance. For example, a first signal threshold and / or a second signal threshold may be optionally selected to prevent or reduce the impact of back reflection on the laser cavity performance. Back reflection occurs when a portion of the LIDAR input signal returns to the laser cavity as a returned LIDAR signal. In some cases, approximately 50% of the LIDAR input signal passing through facet 18 returns to the laser cavity. The returned LIDAR signal may affect the performance of the laser cavity if the power of the returned LIDAR signal entering the partial return device 14 does not decrease to a level lower than the power of the outgoing LIDAR signal leaving the partial return device 14 (“power drop”) by more than a minimum power drop threshold. In the illustrated LIDAR chip, the minimum power drop threshold may be around 35 dB (0.03%). Therefore, when the power of the returned LIDAR signal entering the partial return device 14 is no more than 35 dB lower than the power of the outgoing LIDAR signal leaving the partial return device 14, the returned LIDAR signal may affect the performance of the laser cavity.

[0058] Electronic device 62 can operate the output optical attenuator 46 to reduce the effects of low-power drop, such as when the target object is very close or highly reflective, or both. (See from...) Figure 1 It is evident that the output optical attenuator 46, in order to increase the attenuation level, reduces the power of the returning LIDAR signal entering the partial return device 14, and also reduces the power of the returning outgoing LIDAR signal located away from the partial return device 14. Because the output optical attenuator 46 is located away from the partial return device 14, the power of the outgoing LIDAR signal leaving the partial return device 14 is not directly affected by the operation of the output optical attenuator 46. Therefore, the output optical attenuator 46 increases the level of power reduction in order to increase the attenuation level. As a result, electronic devices can employ the optical attenuator 46 to regulate power reduction.

[0059] Additionally, the amplitude of the sampled signal is related to the power decrease. For example, as from... Figure 1 It is evident that the amplitude of the sampled signal is related to the power of the comparison signal. Since the comparison signal is part of the LiDAR input signal, the amplitude of the sampled signal is related to the power of the LiDAR input signal. This result implies that the amplitude of the sampled signal is also related to the power of the returned LiDAR signal, because the returned LiDAR signal is part of the LiDAR input signal. Therefore, the amplitude of the sampled signal is related to the decrease in power.

[0060] Since the amplitude of the sampled signal is related to the power drop, the electronics 62 can use the amplitude of the sampled signal to operate the output optical attenuator to keep the amplitude of the comparison signal power within a target range. For example, the electronics 62 can operate the output optical attenuator 46 to increase the power drop in response to a sampled signal indicating a power drop equal to or below a first threshold, and / or the electronics 62 can operate the output optical attenuator 46 to decrease the power drop in response to a sampled signal indicating a power drop equal to or above a second threshold. In some cases, the first threshold is greater than or equal to a minimum power drop threshold. In one example, the electronics 62 operates the output optical attenuator 46 to increase the power drop in response to a sampled signal amplitude above a first signal threshold, and / or to decrease the power drop in response to a sampled signal amplitude below a second signal threshold. The identifier of one, two, three, or four values ​​of variables selected from the group consisting of the first threshold, the second threshold, the first signal threshold, and the second signal threshold can be determined based on the calibration of the LIDAR chip during setup of the LIDAR chip system.

[0061] When the power of the composite optical signal exceeds the power threshold, the optical sensor may become saturated. When the optical sensor becomes saturated, the amplitude of the data signal reaches its maximum value, and although the power of the composite optical signal increases above the power threshold, this maximum value does not increase. Therefore, when the power of the composite optical signal exceeds the power threshold, data may be lost. During operation, the electronics 62 can adjust the attenuation level provided by the data optical attenuator 44, thus keeping the power of the composite optical signal below the power threshold.

[0062] As from Figure 1 It is evident that the amplitude of the sampled signal is related to the power of the comparison signal. Therefore, the electronics 62 can operate the data optical attenuator 44 in response to the output from the sampled signal. For example, when the amplitude of the sampled signal indicates that the power of the comparison signal is higher than an upper comparison signal threshold, the electronics 62 can operate the data optical attenuator to increase the attenuation of the comparison signal, and / or when the amplitude of the sampled signal indicates that the power of the comparison signal is lower than a lower comparison signal threshold, the electronics 62 can operate the data optical attenuator to decrease the attenuation of the comparison signal. For example, in some cases, when the amplitude of the sampled signal is at or above the upper comparison threshold, the electronics 62 can increase the attenuation of the comparison signal, and / or when the amplitude of the sampled signal is at or below the upper comparison signal threshold, the electronics 62 can decrease the attenuation of the comparison signal.

[0063] As noted above, the electronic device 62 can adjust the attenuation level provided by the output optical attenuator 46 in response to the sampling signal. In addition to adjusting the attenuation level provided by the output optical attenuator 46 in response to the sampling signal, or as an alternative, the electronic device 62 can adjust the attenuation level provided by the data optical attenuator 44 in response to the sampling signal.

[0064] Suitable platforms for LIDAR chips include, but are not limited to, silicon dioxide, indium phosphide, and silicon-on-insulator wafers. Figure 2 This is a partial cross-section of a LIDAR chip constructed on a silicon-on-insulator (SOI) wafer platform. The SOI wafer includes a buried layer 80 between a substrate 82 and a light-transmitting medium 84. In the SOI wafer, the buried layer is silicon dioxide, while the substrate and light-transmitting medium are silicon. The substrate of an optical platform such as an SOI wafer can serve as the substrate for the entire LIDAR chip. For example, Figure 1 The optical components shown can be positioned on the top and / or lateral side or above the substrate.

[0065] Figure 2 The LIDAR chip portion illustrated includes a waveguide structure suitable for use with LIDAR chips constructed from silicon-on-insulator wafers. A ridge 86 of the light-transmitting medium extends away from the planar region 88 of the light-transmitting medium. The optical signal is confined between the top of the ridge and the buried oxide layer.

[0066] exist Figure 2 The dimensions of the ridge waveguide are marked in the figure. For example, the ridge has a width marked w and a height marked h. The thickness of the planar region is marked T. These dimensions are more important for LiDAR applications than for other applications because higher levels of optical power are required. The ridge width (marked w) is greater than 1. And less than 4 The ridge height (labeled as h) is greater than 1. And less than 4 The thickness of the flat plate area is greater than 0.5 mm. And less than 3 These dimensions can apply to straight or substantially straight portions of the waveguide, curved portions of the waveguide, and one or more tapered portions of the waveguide. 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, while curved portions and / or tapered portions of the waveguide have dimensions outside these ranges. For example, Figure 1 The tapered portion of the practical waveguide 16 illustrated in the figure can have >4 Width and / or height, and can be in 4 up to 12 Within a certain range. Additionally or alternatively, the curved portion of the waveguide may have a reduced slab 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, which has a thickness greater than or equal to 0.0. And less than 0.5 The thickness. While the dimensions above will generally provide a single-mode configuration for straight or substantially straight sections of the waveguide, they may result in multimode (one or more) tapered sections and / or (one or more) bent sections. Coupling between multimode and single-mode geometries can be accomplished using tapered sections that substantially do not excite higher-order modes. Thus, waveguides can be constructed such that signals carried in the waveguide are carried in single-mode even when carried in waveguide sections with multimode dimensions. Figure 2 The waveguide configuration is applicable to all or some of the waveguides selected from the group consisting of cavity waveguide 12, practical waveguide 16, reference waveguide 27, comparison waveguide 30, first detector waveguide 36, second detector waveguide 38, sampling waveguide 52, control waveguide 57, and interferometer waveguide 60. Figure 2 The waveguide construction disclosed in the context is also suitable for manipulating the waveguides that will be disclosed below.

[0067] The light source 10, which interfaces with the utility waveguide 16, can be a gain element that is separate from and then attached to the LIDAR chip. For example, the light source 10 can be a gain element attached to the LIDAR chip using a flip-chip arrangement.

[0068] The use of a flip-chip arrangement is suitable when the light source 10 is to interface with a ridge waveguide on a LIDAR chip made of silicon on insulator. Examples of suitable interfaces between flip-chip gain elements and ridge waveguides on a chip made of silicon on insulator can be found in U.S. Patent No. 9,705,278, published July 11, 2017, and U.S. Patent No. 5,991,484, published November 23, 1999; each of these patents is incorporated herein by reference in its entirety. The configuration is suitable for use as the light source 10. When the light source 10 is a gain element, the electronics 62 can change the frequency of the emitted LIDAR signal by varying the current level applied through the gain element.

[0069] An attenuator can be a component that is separate from and then attached to the LIDAR chip. For example, an attenuator can be included on an attenuator chip that is attached to the LIDAR chip in a flip-chip arrangement. The use of an attenuator chip is applicable to all or some of the attenuators selected from the group consisting of data attenuators and control attenuators.

[0070] As an alternative to including attenuators on separate components, all or part of the attenuators can be integrated with the LiDAR chip. For example, an example of an attenuator docked with a ridge waveguide on a LiDAR chip made of silicon-on-insulator wafer can be found in U.S. Patent No. 5,908,305, published June 1, 1999; each of those patents is incorporated herein by reference in its entirety. The use of attenuators integrated with LiDAR chips is suitable for all or part of optical sensors selected from the group consisting of data attenuators and control attenuators.

[0071] Optical sensors that interface with waveguides on a LiDAR chip can be components that are detached from and then attached to the LiDAR chip. For example, the optical sensor could 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 Corporation in Hamamatsu City, Japan, or InGaAs APDs (avalanche photodiodes) manufactured by Hamamatsu Corporation in Hamamatsu City, Japan. These optical sensors can be centrally positioned on the LiDAR chip, such as... Figure 1 As illustrated in the diagram. Alternatively, all or part of the waveguide terminating at the optical sensor may terminate at a facet 18 located at the edge of the LIDAR chip, and the optical sensor may be attached to the edge of the LIDAR chip above the facet 18, such that the optical sensor receives light passing through the facet 18. The use of the optical sensor as a component separate from the LIDAR chip is applicable to all or part of the optical sensors selected from the group consisting of the first optical sensor 40, the second optical sensor 42, the sampling optical sensor 54, and the control optical sensor 61.

[0072] As an alternative to optical sensors acting as discrete components, all or part of the optical sensors can be integrated with a LiDAR chip. Examples of optical sensors that interface with a ridge waveguide on a LiDAR chip made of silicon-on-insulator wafer can be found in: Optics Express Vol. 15, No. 21, 13965-13971 (2007); U.S. Patent No. 8,093,080, issued January 10, 2012; U.S. Patent No. 8,242,432, issued August 14, 2012; and U.S. Patent No. 6,108,8472, issued August 22, 2000, each of which is incorporated herein by reference in its entirety. The use of optical sensors integrated with a LiDAR chip is applicable to all or part of the optical sensors selected from the group consisting of a first optical sensor 40, a second optical sensor 42, a sampling optical sensor 54, and a control optical sensor 61.

[0073] Grating configurations that can be integrated with various optical device platforms are available. For example, a Bragg grating can be formed in a ridge waveguide by forming a groove in the top and / or rear side of the ridge.

[0074] A LIDAR chip can be modified to generate one LIDAR output signal or multiple different LIDAR output signals. For example, Figure 3A yes Figure 1 A schematic diagram of a LiDAR chip, modified to generate one or more different LiDAR output signals. The LiDAR chip includes a light source 110 that outputs an outgoing optical signal, which comprises one or more different channels, each at a different wavelength. The wavelengths of the channels can be periodically spaced such that the increase in wavelength from one channel to the next is constant or substantially constant. Figures 1 to 2 The context discloses a suitable light source 110 for generating a single channel. Suitable light sources 110 for generating multiple channels with periodically spaced wavelengths include, but are not limited to, comb lasers; multiple single-wavelength lasers multiplexed into a single optical waveguide; and sources such as those described in U.S. Patent Application Serial No. 11 / 998,846, filed November 30, 2017, entitled “Multi-Channel Optical Device”, which is incorporated herein by reference in its entirety.

[0075] A utility waveguide 16 receives an outgoing optical signal from a light source 110. A modulator 114 is optionally positioned along the utility waveguide 16. The modulator 114 is configured to modulate the power of the outgoing optical signal and, consequently, modulate one or more LiDAR output signals. Electronic device 62 can operate the modulator 114. Thus, the electronic device 62 can modulate the power of the outgoing optical signal and, consequently, modulate one or more LiDAR output signals. Suitable modulators 114 include, but are not limited to, PIN diode carrier injection devices, Mach-Zehnder modulator devices, and electroabsorption modulator devices. When the modulator 114 is constructed on a silicon-on-insulator platform, a suitable modulator is disclosed in U.S. Patent Application Serial No. 617,810, filed September 21, 1993, entitled Integrated Silicon PIN Diode Electro-Optic Waveguide, which is incorporated herein by reference in its entirety.

[0076] Amplifier 116 may optionally be positioned along utility waveguide 16. Since the power of the emitted optical signal is distributed across multiple channels, it may be desirable for amplifier 116 to provide the desired power level for each channel along utility waveguide 16. Suitable amplifiers include, but are not limited to, semiconductor optical amplifiers (SOAs).

[0077] The practical waveguide 16 carries the outgoing optical signal from the modulator 114 to the signal guiding component 118. The signal guiding component 118 can guide the outgoing optical signal to the LIDAR branch 120 and / or the data branch 122. The LIDAR branch outputs the LIDAR output signal and receives the LIDAR input signal. The data branch processes the LIDAR input signal to generate LIDAR data (distance and / or radial velocity between the LIDAR output signal source and the reflecting object).

[0078] The LIDAR branch includes a LIDAR signal waveguide 124 that receives at least a portion of the outgoing optical signal from the signal guiding component 118. The LIDAR signal waveguide 124 carries at least a portion of the outgoing optical signal to the output component 126. When the outgoing optical signal includes multiple different channels at different wavelengths, the output component 126 separates the outgoing optical signal into multiple LIDAR output signals, each at a different wavelength (channel) and guided to a different sample region in the field of view. The output component 126 outputs a LIDAR output signal that can be reflected by a reflective object (not shown) located outside the LIDAR system. The reflected LIDAR output signal is returned to the output component 126 as a LIDAR input signal. The output component 126 combines the LIDAR input signals and outputs the result as an incoming optical signal on the LIDAR signal waveguide 124.

[0079] In some cases, output component 126 also includes beam manipulation functionality. In these cases, output component 126 can be in electrical communication with electronics 62. Electronics 62 can operate output component 126 to manipulate the LIDAR output signal to different sample regions in the field of view. Output component 126 and / or electronics 62 can be configured such that different LIDAR output signals can be manipulated independently or simultaneously.

[0080] Although output component 126 is illustrated as a single component, it may include multiple optical and / or electronic components. Suitable output components 126 include, but are not limited to, optical phased arrays (OPAs), transmission diffraction gratings, reflection diffraction gratings, and diffractive optical elements (DOEs). Suitable output components 126 with beam manipulation capabilities include, but are not limited to, optical phased arrays (OPAs) with active phase control elements on an arrayed waveguide.

[0081] LIDAR signal waveguide 124 carries the incoming optical signal to signal guiding component 118. Signal guiding component 118 guides the incoming optical signal to practical waveguide 16 and / or comparison signal waveguide 128. The portion of the incoming optical signal guided to comparison signal waveguide 128 serves as the comparison incoming optical signal.

[0082] The comparison signal waveguide 128 carries the input comparison optical signal to the comparison demultiplexer 130. When the comparison optical signal includes multiple channels, the comparison demultiplexer 130 divides the input comparison optical signal into different comparison signals, each with a different wavelength. The comparison demultiplexer 130 outputs comparison signals on different comparison waveguides 132. Each comparison waveguide 132 carries one comparison signal to a different processing unit 134.

[0083] The signal guiding component 118 is configured such that when the signal guiding component 118 guides at least a portion of the incoming optical signal to the comparison waveguide 132, the signal guiding component 118 also guides at least a portion of the outgoing optical signal to the reference signal waveguide 136. The portion of the outgoing optical signal received by the reference signal waveguide 136 serves as the reference optical signal.

[0084] Reference signal waveguide 136 carries the reference optical signal to reference demultiplexer 138. When the reference optical signal includes multiple channels, reference demultiplexer 138 divides the reference optical signal into different reference signals, each with a different wavelength. Reference demultiplexer 138 outputs reference signals on different reference waveguides 140. Each reference waveguide 140 carries a reference signal to a different processing unit 134.

[0085] Comparison waveguide 132 and reference waveguide 140 are configured such that the comparison signal and the corresponding reference signal are received at the same processing unit 134. For example, comparison waveguide 132 and reference waveguide 140 are configured such that comparison signals and corresponding reference signals of the same wavelength are received at the same processing unit 134.

[0086] As will be described in more detail below, each of the processing units 134 combines the comparison signal with a corresponding reference signal to form a composite signal carrying LiDAR data of the sample region in the field of view. Therefore, the composite signal can be processed to extract the LiDAR data of the sample region.

[0087] The signal guiding component 118 can be an optical coupler. When the signal guiding component 118 is an optical coupler, it guides a first portion of the outgoing optical signal to the LIDAR signal waveguide 124 and a second portion of the outgoing optical signal to the reference signal waveguide 136. It also guides a first portion of the incoming optical signal to the practical waveguide 16 and a second portion of the incoming optical signal to the comparison signal waveguide 128. Therefore, the second portion of the incoming optical signal can act as a comparison incoming optical signal, and the second portion of the outgoing optical signal can act as a reference optical signal.

[0088] The signal guiding component 118 can be an optical switch, such as a cross switch. A suitable cross switch can operate in either cross mode or through mode. In through mode, the outgoing optical signal is guided to the LIDAR signal waveguide 124, and the incoming optical signal is guided to the utility waveguide 16. In cross mode, the outgoing optical signal is guided to the reference signal waveguide 136, and the incoming optical signal is guided to the comparison signal waveguide 128. Therefore, the incoming optical signal or a portion thereof can serve as the comparison optical signal, and the outgoing optical signal or a portion thereof can serve as the reference optical signal.

[0089] Optical switches, such as cross switches, can be controlled by electronic devices. For example, the electronic devices can control the operation of the switch, causing it to be in either cross mode or through mode. When a LIDAR output signal is being transmitted from the LIDAR system, the electronic devices operate the switch, causing it to be in through mode. When the LIDAR system is about to receive a LIDAR input signal, the electronic devices operate the switch, causing it to be in cross mode. Compared to the use of an optical coupler as a signal guiding component 118, the use of a switch can provide a lower level of optical loss.

[0090] In the above description of the operation of the signal guiding unit 118, the comparison optical signal and the reference optical signal are simultaneously guided to the data branch. As a result, the processing unit 34 can each combine the comparison signal with the corresponding reference signal.

[0091] In some cases, the optical amplifier 142 may be positioned along the LIDAR signal waveguide 124 and configured to provide amplification of the outgoing and / or incoming optical signals. This reduces the impact of optical losses at the signal guiding component 118.

[0092] Light from a laser source is typically linearly polarized, and therefore, the LIDAR output signal is also typically linearly polarized. Reflection from the target can alter the polarization angle of the returning light. Therefore, the LIDAR input signal can include light with different linear polarities. For example, a first portion of the LIDAR input signal may include light with a first linear polarization, and a second portion may include light with a second linear polarization. The intensity of the resulting composite signal is proportional to the square of the cosine of the angle between the polarizations of the comparison and reference signals. If the angle is 90 degrees, LIDAR data may be lost in the resulting composite signal. Consequently, the LIDAR system can be modified to compensate for the polarization change in the LIDAR output signal.

[0093] Figure 3B The diagram shows... Figure 3AThe LIDAR system is modified to include an optical circulator as a signal guiding component 118. The optical circulator is configured such that the outgoing optical signal is guided to the LIDAR signal waveguide 124, and the incoming optical signal is guided to the comparison signal waveguide 128. The comparison signal waveguide 128 carries the compared incoming optical signal to the comparison demultiplexer 130. Additionally, a tapping component 144 is positioned along a utility waveguide 16. The tapping component 144 is configured to tap a first portion of the outgoing optical signal such that the first portion of the outgoing optical signal is received on a reference signal waveguide 136. The first portion of the outgoing optical signal received by the reference signal waveguide 136 serves as a reference optical signal. The reference signal waveguide 136 carries the reference optical signal to a reference demultiplexer 138. Accordingly, electronic devices can operate as follows: Figure 3A Contextually disclosed Figure 3B LiDAR systems. Suitable optical circulators include, but are not limited to, fiber optic circulators based on Faraday rotators and integrated optical circulators. Although Figure 3B The signal guiding component 118 is disclosed as an optical circulator, but Figure 3B The signal guiding component 118 can be an optical coupler or an optical switch.

[0094] Figure 4 yes Figure 3A and / or Figure 3B A schematic diagram of a LiDAR system, modified to compensate for polarization changes in the LiDAR output signal. A tap unit 144 is positioned along a practical waveguide 16. The tap unit 144 is configured to tap a first portion of the outgoing optical signal such that the first portion of the outgoing optical signal is received on a first reference signal waveguide 146. The first portion of the outgoing optical signal received by the first reference signal waveguide 146 serves as a first reference optical signal. The tap unit 144 is also configured to tap a second portion of the outgoing optical signal such that the second portion of the outgoing optical signal is received on a second reference signal waveguide 148. The second portion of the outgoing optical signal received by the second reference signal waveguide 148 serves as a second reference optical signal.

[0095] The first reference signal waveguide 146 carries the first reference optical signal to the first reference demultiplexer 150. When the first reference optical signal includes multiple channels, the first reference demultiplexer 150 divides the first reference optical signal into different first reference signals, each with a different wavelength. The first reference demultiplexer 150 outputs the first reference signals on different first reference waveguides 152. Each first reference waveguide 152 carries one of the first reference signals to one of several first processing units 154.

[0096] The second reference signal waveguide 148 carries the second reference optical signal to the second reference demultiplexer 156. When the second reference optical signal includes multiple channels, the second reference demultiplexer 156 divides the second reference optical signal into different second reference signals, each with a different wavelength. The second reference demultiplexer 156 outputs the second reference signals on different second reference waveguides 158. Each second reference waveguide 158 carries one of the second reference signals to one of the plurality of second processing units 160.

[0097] The practical waveguide 16 carries the outgoing optical signal to the signal guiding component 118. The signal guiding component 118 guides the outgoing optical signal to the LIDAR signal waveguide 124. The LIDAR signal waveguide 124 receives the incoming optical signal from the output component 126 and carries the incoming optical signal to the signal guiding component 118. The signal guiding component 118 guides the incoming optical signal to the intermediate waveguide 162. Suitable signal guiding components 118 include, but are not limited to, circulators, 2x2 optical couplers, 1x2 optical couplers, and switches.

[0098] Intermediate waveguide 162 carries the receiving portion of the incoming optical signal to beamsplitter 164. Beamsplitter 164 splits the beam into a preceding comparison incoming signal and a second comparison incoming signal. The preceding comparison incoming signal is received on preceding comparison signal waveguide 165, and the second comparison incoming signal is received on second comparison signal waveguide 166. Preceding comparison signal waveguide 165 carries the preceding comparison incoming signal to polarization rotator 167. Polarization rotator outputs the first comparison incoming signal received on first comparison signal waveguide 169. First comparison signal waveguide 169 carries the first comparison incoming signal to first comparison demultiplexer 168, and second comparison signal waveguide 166 carries the second comparison incoming signal to second comparison demultiplexer 170.

[0099] When the first comparison input optical signal includes multiple channels, the first comparison demultiplexer 168 divides the first comparison input optical signal into different first comparison signals, each with a different wavelength. The first comparison demultiplexer 168 outputs the first comparison signals on different first comparison waveguides 172. Each first comparison waveguide 172 carries one of the first comparison signals to a different first processing unit 154.

[0100] When the second comparison optical signal includes multiple channels, the second comparison demultiplexer 170 divides the first comparison incoming optical signal into different second comparison signals, each with a different wavelength. The second comparison demultiplexer 170 outputs the second comparison signals on different second comparison waveguides 174. Each of the second comparison waveguides 174 carries one of the second comparison signals to a different second processing unit 160.

[0101] The first comparison waveguide 172 and the first reference waveguide 152 are configured such that a comparison signal and a corresponding reference signal are received at the same first processing unit 154. For example, the first comparison waveguide 172 and the first reference waveguide 152 are configured such that a first comparison signal and a first reference signal of the same wavelength are received at the same first processing unit 154.

[0102] The second comparison waveguide 174 and the second reference waveguide 158 are configured such that a comparison signal and a corresponding reference signal are received at the same second processing unit 160. For example, the second comparison waveguide 174 and the second reference waveguide 158 are configured such that a second comparison signal and a second reference signal of the same wavelength are received at the same second processing unit 160.

[0103] Each of the first processing units 154 combines a first comparison signal with a corresponding first reference signal to form a first composite signal carrying LIDAR data of a sample region in the field of view. Each of the second processing units 160 combines a second comparison signal with a corresponding second reference signal to form a second composite signal carrying LIDAR data of a sample region in the field of view.

[0104] The LIDAR system is configured such that the first comparison signal has the same polarization angle as the corresponding second comparison signal. For example, beam splitter 164 can be a polarization beam splitter. An example of a polarization beam splitter is configured such that a channel in the preceding comparison incoming signal has a first polarization but no or substantially no second polarization, and a channel in the second comparison incoming signal has a second polarization but no or substantially no first polarization. For example, a polarization beam splitter can route a portion of the incoming optical signal with the first polarization to the preceding comparison signal waveguide 165 and a portion of the incoming optical signal with the second polarization to the second comparison signal waveguide 166. The first and second polarizations can be linear polarities, and the second polarization is different from the first polarization. For example, the first polarization can be TE and the second polarization can be TM, or the first polarization can be TM and the second polarization can be TE. Suitable beam splitters include, but are not limited to, Wollaston prisms, MEMS-based polarization beam splitters, integrated optical polarization beam splitters using asymmetric y-branching, Mach-Zehnder interferometers, and multimode interference couplers.

[0105] A polarization rotator can be configured to change the polarization of a channel in a preceding comparison input signal from a first polarization to a second polarization. As a result, the channel in the first comparison input signal has the second polarization but has little or no first polarization. Therefore, the channel in the first comparison input signal and the corresponding channel in the second comparison input signal each have the same polarization (the second polarization in this discussion). The first comparison signal resulting from the first comparison input signal has the same polarization angle as the corresponding second comparison signal resulting from the second comparison input signal. Suitable polarization rotators include, but are not limited to, rotation of polarization-maintaining fibers, Faraday rotators, half-wave plates, MEMS-based polarization rotators, integrated optical polarization rotators using asymmetric y-branching, Mach-Zehnder interferometers, and multimode interference couplers.

[0106] Because the LIDAR output signals (one or more) are linearly polarized, the first reference signal can have the same linear polarization angle as the corresponding second reference signal. For example, the first and second reference signals can each have the same polarization as the first and second comparison input signals. Therefore, the first comparison signal, the second comparison signal, the first reference signal, and the second reference signal can each have the same polarization. In this example, the first comparison signal, the second comparison signal, the first reference signal, and the second reference signal can each have light with a second polarization.

[0107] As a result of the above configuration, each of the first composite signals is caused by combining a reference signal and a comparison signal of the same polarization, and will accordingly provide a desired beat between the reference signal and the comparison signal. For example, each of the first composite signals is caused by combining a reference signal and a comparison signal of the first polarization, and excludes or substantially excludes light of the second polarization, or each of the first composite signals is caused by combining a reference signal and a comparison signal of the second polarization, and excludes or substantially excludes light of the first polarization. Similarly, each of the second composite signals includes a reference signal and a comparison signal of the same polarization, and will accordingly provide a desired beat between the reference signal and the comparison signal. For example, each of the second composite signals is caused by combining a reference signal and a comparison signal of the first polarization, and excludes or substantially excludes light of the second polarization, or each of the first composite signals is caused by combining a reference signal and a comparison signal of the second polarization, and excludes or substantially excludes light of the first polarization.

[0108] The above configuration results in the LiDAR data for a single sample region in the field of view appearing in multiple different composite signals (i.e., a first composite signal and a second composite signal) generated for the sample region. In some cases, determining the LiDAR data for the sample region involves electronics combining LiDAR data from the different composite signals (i.e., the first composite signal and the second composite signal). Combining LiDAR data may include averaging, medianing, or modulus-based calculations of the LiDAR data generated from multiple different composite signals. For example, the electronics may average the distance between the LiDAR output signal source and a reflecting object determined according to the first composite signal with the distance determined according to the second composite signal, and / or the electronics may average the radial velocity between the LiDAR output signal source and the reflecting object determined according to the first composite signal with the radial velocity determined according to the second composite signal.

[0109] In some cases, determining the LiDAR data for a sample region involves the electronic device identifying one or more composite signals (i.e., a first composite signal and / or a second composite signal) as the source of LiDAR data that best represents reality (representative LiDAR data). The electronic device can then use the LiDAR data from the identified composite signals as representative LiDAR data for additional processing. For example, the electronic device can identify signals with larger amplitudes (the first or second composite signal) as representative LiDAR data and can use the LiDAR data from the identified signals for further processing by the LiDAR system. In some cases, the electronic device combines composite signals that identify representative LiDAR data with combined LiDAR data from different LiDAR signals. For example, the electronic device can identify each composite signal with an amplitude above an amplitude threshold as representative LiDAR data, and when more than two composite signals are identified as representative LiDAR data, the electronic device can combine the LiDAR data from each identified composite signal. When a composite signal is identified as representative LiDAR data, the electronic device can use the LiDAR data from that composite signal as representative LiDAR data. When no composite signal is identified as representative LiDAR data, the electronic device can discard the LiDAR data of the sample regions associated with those composite signals.

[0110] although Figure 4 This is described in the context of components being arranged such that the first comparison signal, the second comparison signal, the first reference signal, and the second reference signal each have a second polarization, but... Figure 4Other configurations of the components can be arranged such that the first composite signal is caused by a combination of a reference signal and a comparison signal with the same linear polarization, and the first composite signal is caused by a combination of the reference signal and the comparison signal with the same linear polarization. For example, the polarization rotator can be positioned along the first reference signal waveguide 146 instead of between the preceding comparison signal waveguide 165 and the first comparison signal waveguide 169. As another example, when the first reference signal and the second reference signal each have a first polarization, the polarization rotator can be positioned along the second comparison signal waveguide 166.

[0111] The system configuration described above causes a first portion (with a first polarization) and a first portion (with a second polarization) of the LIDAR input signal to be guided into different composite signals. For example, the system configuration may cause the first composite signal to include more power from the first portion of the LIDAR input signal than the first composite signal, and the second composite signal to include more power from the second portion of the LIDAR input signal than the first composite signal. Alternatively, the system configuration may cause the first composite signal to include more power from the second portion of the LIDAR input signal than the first composite signal, and the second composite signal to include more power from the first portion of the LIDAR input signal than the first composite signal. In some cases, the first portion of the LIDAR input signal has zero power or substantially zero power, or the second portion of the LIDAR input signal has zero power or substantially zero power.

[0112] although Figures 3A to 4 The LIDAR chip is disclosed in the context of generating multiple LIDAR output signals, but Figures 3A to 4 The LIDAR chip can be configured and / or operated to generate or output a LIDAR output signal. For example, light source 110 can output a single channel.

[0113] The LIDAR system described above can include more than one data branch associated with a LIDAR branch. For example, Figure 5 The diagram illustrates a LIDAR system in which multiple light sources 110 provide channels to LIDAR branches, and multiple data branches receive optical signals from the LIDAR branches.

[0114] Although the LIDAR system described above is illustrated as having a single light source 110 in each component assembly, the light source 110 may include multiple light sources. For example, Figure 6The illustration shows a light source 110, which includes M photon sources 111, each photon source 111 generating N channels. Each channel is received on a channel waveguide 180. The channel waveguide carries the channels to a channel multiplexer 182, which combines the channels to form an outgoing optical signal received on a practical waveguide 16.

[0115] exist Figure 6 In the middle, each channel is labeled as , where i is the number of photon sources 111, ranging from 1 to M, and j is the number of channels of photon source j, ranging from 1 to N. As noted above, photon sources 111 can be configured such that the wavelengths of the channels are periodically spaced, such that the wavelength increases from one channel to the next ( The photon source 111 is constant or substantially constant. In some cases, the photon source 111 is configured such that channels with adjacent wavelengths are generated by different photon sources 111. For example, the photon source 111 can be configured such that... Suitable photon sources 111 for this configuration include, but are not limited to, comb lasers. In this configuration, the channel multiplexer can be a cyclic multiplexer designed to have wavelength spacing equal to a multiple of the channel multiplexer's free spectral range (FSR). Therefore, channel multiplexers can be designed to operate within a wavelength range ( (Inner loop.) Suitable cyclic multiplexers include, but are not limited to, the “colorless” AWG (8-channel cyclic array waveguide grating, 2018) from Gemfire.

[0116] Suitable values ​​(M) for the number of photon sources 111 include, but are not limited to, values ​​greater than or equal to 2, 4, or 8 and / or less than 16, 32, or 64. Suitable values ​​(N) for the number of channels provided by photon sources 111 include, but are not limited to, values ​​greater than or equal to 2, 4, or 8 and / or less than 16, 32, or 64. Suitable values ​​for the wavelength increase from one channel to the next ( This includes, but is not limited to, values ​​greater than or equal to 0.2 nm, 0.4 nm, or 0.6 nm and / or less than 0.8 nm, 1.0 nm, or 1.5 nm. Suitable wavelength values ​​for the channel with the shortest wavelength include, but are not limited to, values ​​greater than or equal to 1.3 nm. 1.4 Or 1.5 And / or less than 1.6 1.7 Or 1.8 The values ​​of . In one example, a LIDAR system includes M greater than or equal to 2, 4, or 8 and / or less than 16, 32, or 64; N greater than or equal to 2, 4, or 8 and / or less than 16, 32, or 64; and N greater than or equal to 0.2 nm, 0.4 nm, or 0.6 nm and / or less than 0.8 nm, 1 nm, or 1.5 nm. .

[0117] In some cases, the light source 110 is configured such that at least a portion of the photon source 111 each generates two or more channels having adjacent wavelengths. For example, the photon source 111 can be configured such that... Suitable photon sources 111 for this configuration include, but are not limited to, comb lasers. In this configuration, the channel multiplexer can be one with at least [missing information - likely a specific function or feature]. Wideband multiplexers with high bandwidth. Suitable wideband multiplexers include, but are not limited to, arrayed waveguide gratings (AWGs) and thin-film filters.

[0118] As noted above, one or more of the light source and / or photon source can be a comb laser. However, other configurations of the light source 110 are possible. For example, Figure 7 An example of a light source 110 or photon source 111 including multiple laser sources 184 is illustrated. Figure 7 The light source 110 or photon source 111 illustrated includes multiple laser sources 184, each laser source 184 outputting one channel on a source waveguide 186. The source waveguide 186 carries the channel to a laser multiplexer 188, which combines the channels to form an optical signal received on a channel waveguide or practical waveguide 16. Electronic devices can operate the laser sources 184, thus allowing each laser source 184 to output each channel simultaneously. (Compared to...) Figure 7 Suitable lasers used with the constructed light source 110 or photon source 111 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 due to their generally narrower linewidth—which reduces noise in the detection signal.

[0119] Figure 8 Another example of the possible construction of a light source 110 or photon source 111 is illustrated. The light source 110 or photon source 111 includes a gain element 190, such as a gain element of a semiconductor laser. A gain waveguide 192 is optically aligned with the gain element to receive an optical signal from the gain element. In some cases, the gain waveguide excludes the gain medium contained within the gain element. For example, the gain waveguide could be a ridge waveguide on a silicon-on-insulator chip. Multiple partial return devices 194 are positioned along the gain waveguide such that the partial return devices interact with the optical signal.

[0120] During operation, the electronic devices operate the gain element, causing the gain medium to output an optical signal. Partial return devices 194 each pass a portion of the optical signal. The portion of the optical signal received by the practical waveguide 16 from the partial return device acts as the outgoing optical signal. The partial return device also returns a portion of the optical signal to the gain element, causing the returned portion of the optical signal to travel through the gain element. The gain element may include a total reflection layer or a partial reflection layer that receives the returned portion of the optical signal from the gain element and reflects it back to the gain element, thereby allowing the returned portion of the optical signal to be amplified and emitted as laser light. Therefore, the light source 110 or photon source 111 may be an external cavity laser.

[0121] Partial return devices can be configured such that each partial return device returns light of a different wavelength. For example, partial return devices can be configured such that at least one partial return device returns the wavelength of each channel output by the light source 110. As a result, each desired channel will emit laser light and appear in the outgoing optical signal. Suitable partial return devices include, but are not limited to, Bragg gratings.

[0122] All or part of the processing component 134 can be as follows Figure 1 It is constructed and / or operated as disclosed in the context of A. However, processing component 134 may have other construction and / or operating principles. As an example, Figures 9A to 9B An example of a suitable processing component 134 for use in a LiDAR chip and / or LiDAR system is illustrated. A first splitter 202 divides a reference signal carried on reference waveguides 27, 140, 152, or 158 onto 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 combining component 211. The second reference waveguide 208 carries a second portion of the reference signal to a second optical combining component 212.

[0123] The second splitter 200 divides the comparison signal carried on comparison waveguides 30, 130, 172, or 174 onto the first comparison waveguide 204 and the second comparison waveguide 206. The first comparison waveguide 204 carries a first portion of the comparison signal to the optical combination unit 211. The second comparison waveguide 208 carries a second portion of the comparison signal to the second optical combination unit 212.

[0124] The second optical combining component 212 combines the second portion of the comparison signal and the second portion of the reference signal into a second composite signal. Due to the frequency difference between the second portion of the comparison signal and the second portion of the reference signal, the second composite signal beats between the second portion of the comparison signal and the second portion of the reference signal. The optical combining component 212 also separates the resulting second composite signal onto the first auxiliary detector waveguide 214 and the second auxiliary detector waveguide 216.

[0125] First auxiliary detector waveguide 214 carries a first portion of the second composite signal to first auxiliary optical sensor 218, which converts the first portion of the second composite signal into a first auxiliary electrical signal. Second auxiliary detector waveguide 216 carries a second portion of the second composite signal to 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).

[0126] The first optical combining component 211 combines a first portion of the comparison signal and a first portion of the reference signal into a first composite signal. Due to the frequency difference between the first portion of the comparison signal and the first portion of the reference signal, the first composite signal beats between the first portion of the comparison signal and the first portion of the reference signal. The optical combining component 211 also separates the first composite signal onto a first detector waveguide 221 and a second detector waveguide 222.

[0127] First detector waveguide 221 carries a first portion of the first composite signal to first optical sensor 223, which converts the first portion of the second composite signal into a first electrical signal. Second detector waveguide 222 carries a second portion of the second composite signal to second auxiliary 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).

[0128] The first reference waveguide 210 and the second reference waveguide 208 are configured to provide a phase shift between a first portion 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 and the second portion of the reference signal. As an example, one reference signal portion can be an in-phase component, and the other can be a quadrature component. Therefore, one of the reference signal portions can be a sine function, and the other can be a cosine function. In one example, the first reference waveguide 210 and the second reference waveguide 208 are configured such that the first reference signal portion is a cosine function, and the second reference signal portion is a sine function. Therefore, the reference signal portion in the second composite signal is phase-shifted relative to the reference signal portion in the first composite signal; however, the comparison signal portion in the first composite signal is not phase-shifted relative to the comparison signal portion in the second composite signal.

[0129] The first optical sensor 223 and the second optical sensor 224 can be connected as a balanced detector, and the first auxiliary optical sensor 218 and the second auxiliary optical sensor 220 can also be connected as a balanced detector. For example, Figure 9B A schematic diagram is provided showing the relationship between electronic devices, a first light sensor 223, a second light sensor 224, a first auxiliary light sensor 218, and a second auxiliary light sensor 220. The symbol for a photodiode is used to represent the first light sensor 223, the second light sensor 224, the first auxiliary light sensor 218, and the second auxiliary light sensor 220; however, one or more of these sensors may have other configurations. In some cases, Figure 9B All components illustrated in the diagram are included in the LIDAR system. In some cases, Figure 9B The components shown in the schematic diagram are distributed between the LIDAR system and the electronic devices located outside the LIDAR system.

[0130] The electronic device connects the first optical sensor 223 and the second optical sensor 224 to form a first balanced detector 225, and connects the first auxiliary optical sensor 218 and the second auxiliary optical sensor 220 to form a second balanced detector 226. Specifically, the first optical sensor 223 and the second optical sensor 224 are connected in series. Additionally, the first auxiliary optical sensor 218 and the second auxiliary optical sensor 220 are connected in series. The serial connection in the first balanced detector communicates with a first data line 228, which carries the output from the first balanced detector as a first data signal. The serial connection in the second balanced detector communicates with a second data line 232, which carries the output from the first balanced detector as a second data signal. 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, the first data signal and the second data signal are beating.

[0131] The first data line 228 carries the first data signal to the first switch 234. The first switch can be in a first configuration, where the first data signal is carried to the distance branch 136; or in a second configuration, where the first data signal is carried to the speed branch 238. Figure 9B In the diagram, the first switch 234 is shown in a first configuration. The second data line 232 carries a second data signal to the second switch 240. The second switch can be in the first configuration, where the second data signal is carried to the distance branch 236; or in the second configuration, where the second data signal is carried to the speed branch 238. Figure 9B In the diagram, the second switch 240 is shown in the first configuration. Suitable switches used as the first and / or second switches include, but are not limited to, electromechanical switches and solid-state MOSFET or PIN diode switches.

[0132] The electronic device operates the first switch and the second switch such that they are in the same configuration during a first time period and a second time period. For example, the electronic device can operate the first switch and the second switch such that both the first switch and the second switch are in a first configuration during the first time period and in a second configuration during the second time period. In this example, the first data signal and the second data signal are carried to the distance branch 236 during the first time period and to the speed branch 238 during the second time period.

[0133] During LIDAR system operation, LIDAR data generation is divided into a series of cycles, with LIDAR data generated for each cycle. In some cases, each cycle corresponds to a different sample region in the field of view. Therefore, different cycles can generate LIDAR data for different sample regions in the field of view.

[0134] A loop can be executed, allowing the time of each loop to be divided into different time periods, including a distance time period (first time period) and a velocity time period (second time period). The distance between the reflective object and the LiDAR chip can be determined within the distance time period, and the radial velocity between the reflective object and the LiDAR chip can be determined within the velocity time period.

[0135] The electronic device is configured to use a first data signal and a second data signal to determine or at least approximate the distance between the LIDAR system and the reflecting object. For example, during a first time period, the electronic device may operate modulator 114 to add linear frequency modulation to the amplitude of the outgoing LIDAR signal and, correspondingly, the LIDAR output signal. Adding linear frequency modulation to the amplitude may include modulating the amplitude of the outgoing LIDAR signal such that the amplitude of the outgoing LIDAR signal is a function of a sine curve. In one example, the amplitude of the outgoing LIDAR signal is modulated such that the amplitude of the outgoing LIDAR signal is the square root of a function including a sine curve and / or the square root of a sine curve. For example, the outgoing LIDAR signal may be modulated to produce a modulated outgoing LIDAR signal and mathematically derived from Equation 1: The LIDAR output signal is represented by M, N, C, D, and F, where M, N, C, D, and F are constants, t represents time, and M>0, N>0, and... In order to prevent the radicand from becoming negative, As will become apparent below, F can be the LIDAR output signal frequency (f... c The function of ). In equation 1, we can choose F and C such that .

[0136] The distance branch includes a first distance branch line 242. During a first time period, the first distance branch line 242 carries the first data signal to the first multiplier 244. Figure 9B In this configuration, the first multiplier 244 is configured to square the amplitude of the first data signal and output the first multiplied data signal. The distance branch includes a second distance branch line 246. During a first time period, the second distance branch line 246 carries the second data signal to the second multiplier 248. Figure 9B In this configuration, the second multiplier 248 is configured to square the amplitude of the second data signal and output a second multiplied data signal. Suitable first and / or second multipliers include, but are not limited to, RF mixers, such as Gilbert unit mixers.

[0137] The distance branch includes an adder 250 that adds the first multiplied data signal and the second multiplied data signal. The adder outputs the added data signal. Suitable adders include, but are not limited to, RF combiners, including resistor or hybrid combiners. The distance branch includes a low-pass filter 252 that receives the added data signal and outputs a beat data signal. The low-pass filter is selected to remove high-frequency contributions to the added data signal, which are artifacts caused by the mixing of the reference and return signals. The low-pass filter can be selected to have a frequency greater than or equal to: bandwidth, of which This represents the maximum level of Doppler frequency shift of the LIDAR input signal relative to the LIDAR system, indicating the level at which the LIDAR input signal will provide reliable results. This represents the maximum delay between the transmission of the LIDAR output signal and the reception of the LIDAR input signal, and This represents the rate of change of the linear frequency modulation frequency added to the amplitude of the modulated output LIDAR signal during the duration of the sampling period (i.e., the first period). In some cases, it is determined according to B / T. , where B represents the change in linear frequency modulation added to the amplitude of the modulated output LIDAR signal during the sampling period, and T is the duration of the sampling period. In some cases, T is determined according to the following formula: ,in Indicates the wavelength of the transmitted LIDAR signal. : represents velocity resolution, and B can be determined according to the following formula: Where c represents the speed of light, and This indicates the range resolution. In some cases, the filter has a bandwidth greater than 0.1 GHz, 0.2 GHz, or 0.3 GHz and / or less than 0.4 GHz, 0.5 GHz, or 1 GHz. The corresponding value for the scan period (T) can be 10. 8 4 3 2 and 1 .

[0138] The distance branch includes an analog-to-digital converter (ADC) 254 that receives the beat data signal from the filter. The ADC 254 converts the beat data signal from analog to digital form and outputs the result as a digital LIDAR data signal. As discussed above, the conversion of the beat data signal involves sampling the beat data signal at a sampling rate. Adding linear frequency modulation to the amplitude of the LIDAR output signal significantly reduces or removes the influence of the radial velocity of the beat from the composite signal and the resulting electrical signal. For example, the frequency shift (“frequency shift”) of the LIDAR output signal relative to the LIDAR input signal... ) can be written as ,in This indicates the frequency change caused by the Doppler shift, and This frequency change is due to the separation between the reflecting object and the LIDAR system. The outgoing LIDAR signal can be modulated to produce a modulated outgoing LIDAR signal, and a correspondingly modulated LIDAR output signal, wherein the frequency change is due to the Doppler shift. The frequency shift due to the Doppler shift is less than 10%, 5%, 1%, or even 0.1% of the Doppler frequency shift that would occur from the following sinusoidal LiDAR output signal, which acts as a LiDAR and has a constant amplitude and the same frequency as the modulated output LiDAR signal and / or LiDAR output signal. For example, the output LiDAR signal and / or LiDAR output signal can be modulated to produce a modulated output LiDAR signal and / or LiDAR output signal, wherein the frequency change due to the Doppler frequency shift ( The frequency shift due to the Doppler shift is less than 10%, 5%, 1%, or even 0.1% of the Doppler frequency shift that will occur from the following continuous wave, which acts as the LIDAR output signal and has the same frequency as the modulated outgoing LIDAR signal and / or LIDAR output signal. In another example, the outgoing LIDAR signal and / or LIDAR output signal are modulated to produce a modulated outgoing LIDAR signal and / or LIDAR output signal, wherein the frequency change due to the Doppler frequency shift ( The difference is less than 10%, 5%, 1%, or even 0.1% of the Doppler shift that occurs from the unmodulated output LiDAR signal (the unmodulated output LiDAR signal) that serves as the LiDAR output signal. These results can be achieved by increasing the value of the variable F in Equation 1 relative to C. For example, F can represent... And C can represent ,in This indicates the fundamental frequency of the linearly frequency-modulated amplitude of the modulated LIDAR signal. Therefore, by increasing the frequency of the LIDAR output signal ( ) relative to the linear frequency modulation fundamental frequency ( The value of F can be increased relative to C. As an example, and It can be selected to make In some cases, choose and , making : The ratio is greater than 2:1, 10:1, or 1x10. 4 1.5xl0 4 Or 1xl0 5 : 1 and / or less than 5xl0 5 lxl0 6 5xl0 6 Or 5xl0 8 Therefore, for the F:C ratio, variables F and C can also have these same values. This reduces and / or removes the frequency change due to the Doppler frequency shift from the frequency shift. This reduces the beat frequency and correspondingly reduces the required sampling rate.

[0139] The distance branch includes a transform module 256 that receives digital LiDAR data signals from an analog-to-digital converter (ADC) 254. Transform module 256 is configured to perform a real transform on the digital LiDAR data signals to convert them from the time domain to the frequency domain. This transformation provides a definitive solution to the frequency offset of the LiDAR input signal relative to the LiDAR input signal offset caused by the distance between the reflecting object and the LiDAR system. A suitable real transform is a Fourier transform, such as the Fast Fourier Transform (FFT). Classifying the transform as a real transform distinguishes it from complex transforms, such as the Complex Fourier Transform. The transform module can perform attribute functions using firmware, hardware, or software, or a combination thereof.

[0140] Since the frequency provided by the transformation module does not come from an input of frequency shift due to relative movement, or does not come from a substantial input of frequency shift due to relative movement, the determined frequency shift can be used to approximate the distance between the reflecting object and the LIDAR system. For example, electronic devices can use Equation 3: To approximate the distance between the reflecting object and the LIDAR system (R0), where It can be approximated as the peak frequency output from the transformation module, and c is the speed of light.

[0141] The velocity branch can be configured to use a first data signal and a second data signal to determine, or at least approximate, the radial velocity of the LIDAR system and the reflecting object. Figures 3A to 4 In the context of [the document], a LIDAR output signal with a frequency that is a function of time can be replaced by a LIDAR output signal whose frequency is not a function of time. For example, the LIDAR output signal can be a continuous wave (CW). For example, during the second time period, the modulated outgoing LIDAR signal and the corresponding LIDAR output signal can be a non-linearly frequency-modulated continuous wave (CW). As an example, the modulated outgoing LIDAR signal and the corresponding LIDAR output signal can be obtained from Equation 2: Let G and H be constants, and t represent time. In some cases, G represents the square root of the output LIDAR signal power, and / or H represents the constant F from Equation 1. When the output of the light source has the desired waveform for the modulated output LIDAR signal, the electronics do not need to operate modulator 114 to modify the output LIDAR signal. In these cases, the output of (one or more) light sources can serve as the modulated output LIDAR signal and correspondingly as the LIDAR output signal. In some cases, the electronics operate modulator 114 to generate a modulated output LIDAR signal with the desired form.

[0142] Since the frequency of the LIDAR output signal is constant during the second time period, changing the distance between the reflecting object and the LIDAR system does not cause a change in the frequency of the LIDAR input signal. As a result, the separation distance does not contribute to the frequency shift of the LIDAR input signal relative to the LIDAR output signal. Therefore, the effect of the separation distance has been removed or substantially removed from the frequency shift of the LIDAR input signal relative to the LIDAR output signal.

[0143] The velocity branches include a first velocity branch line 260 and a second velocity branch line 260. During the second time period, the first velocity branch line 260 carries the first data signal to the analog-to-digital converter (ADC) 164, which converts the first data signal from analog to digital form and outputs a first digital data signal. As discussed above, the conversion of the first data signal is accomplished by sampling the first data signal at a sampling rate. Using a continuous wave as the LIDAR output signal essentially removes the beat effect of the distance between the reflecting object and the LIDAR system on the composite signal and the resulting electrical signal. Therefore, beat is reduced, and the required sampling rate is reduced.

[0144] The second speed branch line 262 carries the second data signal to the analog-to-digital converter (ADC) 266, which converts the second data signal from analog to digital form and outputs a second digital data signal. As discussed above, the conversion of the second data signal involves sampling the second data signal at a sampling rate. Using a continuous wave as the LIDAR output signal essentially reduces or eliminates the effect of the distance between the reflecting object and the LIDAR system on the beat of the second composite signal and the resulting electrical signal. Therefore, beat is reduced, and the required sampling rate is lowered.

[0145] The sampling rate of the analog-to-digital converter (ADC) 264 may be the same as or different from that of the analog-to-digital converter (ADC) 266.

[0146] The velocity branch includes a transformation module 268 that receives a first digital data signal from an analog-to-digital converter (ADC) 264 and a second digital data signal from an ADC 266. Since the first data signal is an in-phase component and the second data signal is a quadrature component, the first and second data signals together act as a complex velocity data signal, where the first data signal is a real component and the second data signal is an imaginary component. As a result, the first digital data signal can be the real part of the digital velocity data signal, and the second data signal can be the imaginary part of the digital velocity data signal. The transformation module 168 can be configured to perform a complex transformation on the digital velocity data signal to convert it from the time domain to the frequency domain. This conversion provides a clear solution to the frequency offset of the LiDAR input signal relative to the LiDAR input signal caused by the radial velocity between the reflecting object and the LiDAR system. A suitable complex transformation is a Fourier transform, such as the complex fast Fourier transform (FFT). The transformation module can perform attribute functions using firmware, hardware, or software, or a combination thereof.

[0147] Because the frequency shift provided by the transformation module 268 has no input from the frequency shift due to the separation distance between the reflecting object and the LiDAR system, and due to the complex nature of the velocity data signal, the output of the transformation module 268 can be used to approximate the radial velocity between the reflecting object and the LiDAR system. For example, the electronic device can use Equation 4: To approximate the radial velocity (v) between the reflecting object and the LIDAR system, where Approximately the peak frequency output from the transformation module 268, where c is the speed of light, and This indicates the frequency of the LIDAR output signal.

[0148] Can to Figure 9BThe schematic diagram adds additional components. For example, when a LIDAR system generates multiple LIDAR output signals or is used with other LIDAR systems that generate LIDAR output signals (i.e., by means of frequency division or wavelength division multiplexing, FDM / WMD), the LIDAR system may include one or more filters to remove interfering signals from the real and / or imaginary parts of the beat data signal and / or velocity data signal. Therefore, in addition to the components illustrated, a LIDAR system may include one or more filters. Suitable filters include, but are not limited to, low-pass filters. In the case of optical designs, if the frequency of the interfering component falls outside the bandwidth of the balanced detector(s), additional filtering may not be necessary, as it can be effectively provided by the balanced detector(s).

[0149] The sampling rate used during the first and second time periods can be selected as a value that is greater than or equal to the larger of two values ​​chosen from the group consisting of the minimum sampling rate of the first and second time periods. For example, during the first time period, the sampling rate of the first time period (f s1 The rate range can be determined by Confirmed, among which This represents the maximum amount of time between the transmission of the LIDAR output signal and the reception of the LIDAR input signal. During the second time period, the second time period sampling rate (f...) s2 The rate range can be determined by Confirmed, among which This represents the maximum level of Doppler shift of the LIDAR input signal relative to the LIDAR input signal for which the LIDAR system will provide reliable results. The maximum value is determined by the maximum level for which the LIDAR system will provide reliable results. Therefore, the maximum distance generally corresponds to the field of view distance set in the LIDAR specification, and the maximum Doppler shift generally corresponds to the Doppler shift occurring at the maximum radial velocity value set in the specification. These two equations show that the minimum sampling rate for the first time period is... And the minimum sampling rate for the second time period is As a result, the sampling rate was selected to have a value greater than or equal to and The larger of the two values. In other words, the sampling rate used during the first and second time periods ( )yes In some cases, the sampling rate used during the first and second time periods ( (Greater than or equal to 0.1 GHz, 0.2 GHz or 0.5 GHz and / or less than 1 GHz, 2 GHz or 4 GHz.)

[0150] The above description of the LIDAR system operation assumes the presence of a modulator on the practical waveguide 16; however, the modulator is optional. In these cases, the electronics can operate one or more light sources 10 to increase the frequency of the emitted LIDAR signal during a first time period and decrease the frequency of the emitted LIDAR signal during a second time period. A suitable method for extracting LIDAR data from a resulting composite signal is disclosed in U.S. Patent Application Serial No. 62 / 671,913, filed May 15, 2018, entitled "Optical Sensor Chip," which is incorporated herein by reference in its entirety.

[0151] Figure 9C An example of a suitable output component 126 including beam manipulation capabilities is illustrated. The output component can be coupled with... Figures 1 to 2 And / or according to Figures 3A to 5 The constructed LIDAR chip is used in conjunction with other components. For example, output component 126 includes a splitter 284, which can be used from... Figure 1 Practical waveguide 16 or from Figures 3A to 5 One or more LIDAR signal waveguides 124 receive the outgoing optical signal. A splitter divides the outgoing optical signal into multiple output signals, each of which is carried on a manipulation waveguide 286. Each manipulation waveguide terminates at a facet 288. The facets are arranged such that the output signals exiting the chip through the facets are combined to form the LIDAR output signal.

[0152] The splitter and manipulator waveguides can be configured such that there is no phase difference between the output signals at the facets of adjacent manipulator waveguides. For example, the splitter can be configured such that each output signal leaves the splitter in phase, and each manipulator waveguide can have the same length. Alternatively, the splitter and manipulator waveguides can be configured such that there is a linearly increasing phase difference between the output signals at the facets of adjacent manipulator waveguides. For example, the manipulator waveguide can be configured such that the phase of manipulator waveguide j is... , where j is an integer from 1 to N, and represents the state when the waveguide is manipulated as follows: Figure 8 The numbers shown are sequentially associated with the manipulated waveguides, where f is the phase difference between neighboring manipulated waveguides when the phase tuner (discussed below) does not affect the phase difference, and This refers to the phase of the output signal at the facet of the manipulating waveguide at k=1. Because the channel can have different wavelengths, f and... The values ​​can each be associated with one of the channels. In some cases, this phase difference is achieved by constructing a manipulating waveguide with a linearly increasing length difference. For example, the length of manipulating waveguide j can be determined by... Let k be an integer from 1 to K, and let k represent the state when the waveguide is manipulated as follows: Figure 9CThe sequential numbering shown is associated with the manipulated waveguide. It is the length difference between neighboring manipulator waveguides, and It manipulates the length of the waveguide when k = 1. Because It refers to the different percentages of different channel wavelengths contained in the output signal, so each different LIDAR output signal is in a different direction ( (Move away from the LIDAR chip. When the manipulation waveguide length is the same,) The value of is zero, and the value of f is zero. Suitable Including but not limited to greater than 0 or 5 and / or less than 10 or 15 of Suitable f includes, but is not limited to, f greater than 1. or and / or less than or f. Suitable N includes, but is not limited to, N greater than 10 or 500 and / or less than 1000 or 2000. Demultiplexer 284 does not need to have demultiplexing functionality. Suitable demultiplexer 284 includes, but is not limited to, star couplers, cascaded Y-junctions, and cascaded 1x2 MMI couplers.

[0153] Phase tuners 290 may optionally be positioned along at least a portion of the manipulation waveguide. Although phase tuners are shown positioned along the first and last manipulation waveguides, these phase tuners are optional. For example, the LIDAR chip does not need to include a phase tuner on the manipulation waveguide j=1.

[0154] Electronic devices can be configured to operate phase tuners to create a phase difference between output signals at facets of adjacent manipulated waveguides. The electronic devices can operate the phase tuners such that the phase difference is constant because it linearly increases across the manipulated waveguide. For example, the electronic devices can operate the phase tuner such that the tuner-induced phase of manipulated waveguide k is... , where k is an integer from 1 to N, and represents the waveguide manipulation as Figure 9C The sequential numbering shown is associated with the manipulated waveguide. It is the tuner-induced phase difference between neighboring manipulator waveguides. Therefore, the phase of manipulator waveguide k is . Figure 8 The illustration shows a LiDAR chip with only four maneuvering waveguides for simplification; however, LiDAR chips can include more maneuvering waveguides. For example, a LiDAR chip can include more than four maneuvering waveguides, more than 100 maneuvering waveguides, more than 1000 maneuvering waveguides, and / or less than 10000 maneuvering waveguides.

[0155] Electronic devices can be configured to operate a phase tuner in order to tune the phase difference. The value of the tuning phase difference. The value changes the direction in which the LIDAR output signal travels away from the LIDAR chip. Therefore, electronic devices can change the phase difference. To scan the LIDAR output signal. The angle range that the LIDAR output signal can be scanned is... And in some cases, from Extending to , among which when When = 0, the measurement is performed in the direction of the LIDAR output signal. .when When the value is not zero, the length difference causes diffraction, resulting in light of different wavelengths diffracting in different directions. The signal travels away from the LIDAR chip. Therefore, when the outgoing LIDAR signal travels away from the LIDAR chip, some diffusion of the outgoing LIDAR signal may occur. Furthermore, when... At that time, changing the diffraction level alters the angle at which the emitted LIDAR signal travels away from the LIDAR chip. However, providing a length difference for manipulating the waveguide ( This can simplify the layout of the manipulation waveguide on the LIDAR chip.

[0156] Regarding Figure 9C Additional details regarding the construction and operation of the output component 126 can be found in U.S. Provisional Patent Application Serial No. 62 / 680,787, filed June 5, 2018 and incorporated herein in its entirety.

[0157] A single LIDAR chip can comprise multiple component assemblies. For example, Figure 10 The illustration shows a LiDAR chip serving as a composite LiDAR chip, wherein the LiDAR chip includes a plurality of component assemblies labeled j = 1 to j = J. The illustrated component assemblies are based on... Figure 1 Combined with Figure 9C The processing component 134 is constructed. For simplicity, in... Figure 11 This greatly simplifies the arrangement of the splitter 284, the manipulating waveguide 286, and the phase tuner 290; however, the component assembly may include these components arranged and operating as disclosed elsewhere. Each component assembly operates as disclosed above. Thus, each component assembly is configured to generate one or more LIDAR output signals.

[0158] Figure 10The LIDAR chip in the image shows each component assembly manufactured on the same chip. For example, each component assembly is located on the same substrate or base. However, a LIDAR chip that acts as a composite LIDAR chip can be constructed from multiple LIDAR chips, each manufactured on its own die. Figure 11 As shown, different LIDAR chips can be positioned on a common substrate or a common base plate.

[0159] The above discussion provides for the manipulation of the LIDAR output signal in one dimension. The LIDAR chip can be moved relative to a reflective object to provide scanning in other dimensions. For example, the LIDAR chip can be moved around an axis (such as...) Figure 10 The axis (marked as X) rotates. Electronic devices can communicate with actuator 292 for moving the composite chip relative to the reflective object. Examples of suitable actuators include, but are not limited to, electric motors and piezoelectric-driven rotary actuators. Movement can be controlled to allow scanning of the LIDAR output signal in two dimensions.

[0160] A LIDAR system can be configured to provide incident angle diversity, wherein multiple sample regions in the field of view are simultaneously illuminated by multiple different LIDAR output signals, each LIDAR output signal having a different incident angle on the sample region and / or on a reflecting object 304 located within the sample region. For example, Figure 12 The illustration shows multiple LIDAR chips 300, each outputting a different LIDAR output signal. One of the LIDAR output signals is shown by a dashed line, and another is shown by a solid line.

[0161] Figure 12 The same sample region 302 is shown in the respective guided field of view 305 of the LIDAR output signals. The sample regions are located where there is sufficient overlap between the LIDAR output signals so that the LIDAR data generated from each LIDAR output signal represents the same region of the field of view. Because... Figure 12 The illustration shows a reflective object 304 located in the sample region 302 that receives the LIDAR output signal, so that the LIDAR output signal is reflected back from the sample region in the field of view toward the LIDAR chip.

[0162] exist Figure 12In this context, the incident angles of the LiDAR output signals on the sample region and / or on reflective objects located within the sample region are different. As a result, multiple different LiDAR input signals are generated for the same sample region, and each different LiDAR input signal is associated with a different incident angle. Therefore, there is an option to generate multiple LiDAR data values ​​for a sample region, where each LiDAR data value is associated with a different incident angle. In some cases, the different LiDAR output signals have different wavelengths to reduce crosstalk.

[0163] Figure 12 One or more of the LIDAR chips can be configured to manipulate the LIDAR output signal. For example, one or more of the LIDAR chips can be configured to manipulate the LIDAR output signal according to... Figures 1 to 5 Construction, based on Figure 9C The output component 126 is constructed and / or has in Figure 10 The actuator is disclosed in the context of [the above]. As a result, the electronics 62 can manipulate the LIDAR output signal from one sample region in the field of view to another sample region in the field of view. For example, the electronics 62 can operate each head to manipulate the LIDAR output signal to different sample regions at different distances from one of the two LIDAR chips. Therefore, the sample regions in the field of view can be arranged in one-dimensional, two-dimensional, or three-dimensional space.

[0164] The composite LiDAR chip 300 can also be used to provide incident angle diversity. For example, Figure 13 The diagram illustrates a composite LiDAR chip configured to output multiple LiDAR output signals spaced apart from each other. Fiber optic block 306 attaches multiple fiber optic cables 308 to the composite LiDAR chip 300. The fiber optic cables 308 are aligned with facets on the composite LiDAR chip 300, such that each LiDAR output signal is received on one of the fiber optic cables 308. Each fiber optic cable carries the LiDAR output signal to a head 310 and carries the LiDAR input signal from the head to the composite LiDAR chip 300.

[0165] Head 310 is configured to transmit LIDAR output signals received by the head. Each head may include optics 312 necessary to provide desired optical characteristics for the received LIDAR output signals. For example, all or part of the head may include one or more lenses that collimate, focus, or reduce the divergence of the received LIDAR output signals. The head may be in electrical communication with electronics 62. Electronics 62 may operate each head 310 to manipulate the LIDAR output signals in a desired direction. For example, electronics 62 may operate each head to manipulate the LIDAR output signals toward the same sample region in the field of view, such as... Figure 13As shown in the diagram, the sample region is located where there is sufficient overlap between the LIDAR output signals so that the LIDAR data in each output signal represents the same area of ​​the field of view. The reflective object 304 is located within the sample region. As a result, the LIDAR output signals are reflected back from the field of view toward the LIDAR chip.

[0166] Additionally, the electronics 62 can operate each head to manipulate the LIDAR output signal from one sample region in the field of view to another sample region in the field of view. For example, the electronics 62 can operate each head to manipulate the LIDAR output signal to different sample regions at different distances from one of the two LIDAR chips. Thus, the sample regions in the field of view can be arranged in one-dimensional, two-dimensional, or three-dimensional space. Suitable heads include, but are not limited to, collimators mounted on an electrified platform.

[0167] A LIDAR system can be configured to provide wavelength diversity, where multiple sample regions in the field of view are simultaneously illuminated by multiple different LIDAR output signals, each with a different wavelength. For example, Figure 14 The diagram illustrates a LiDAR chip 300 that outputs multiple LiDAR signals. The first LiDAR output signal is labeled as... And it is illustrated by dashed lines, and the second LIDAR output signal is marked as... And illustrated by solid lines. The LIDAR output signals are directed toward the same sample area, and each signal is at a different wavelength (channel). Sample area 302 is located where there is sufficient overlap between the LIDAR output signals so that the LIDAR data in each output signal represents the same area of ​​the field of view. Figure 14 The reflective object 304 located in the sample area is shown. As a result, the LIDAR output signal is shown as being reflected back from the field of view toward the LIDAR chip.

[0168] Different LIDAR output signals can completely or partially overlap, such as Figure 14 As shown in the diagram. However, different LIDAR output signals can travel away from the LIDAR chip in the same or substantially the same direction. As a result, different LIDAR output signals can be guided along the same or substantially the same optical path between the LIDAR chip and the sample area, and correspondingly along the same optical path between the LIDAR chip and the reflective object. For example, the LIDAR chip can be guided according to... Figures 3A to 4 Construction, based on Figure 9CThe output component 126 is constructed, and the splitter 284 and the manipulation waveguide 286 are configured such that there is no phase difference between the LIDAR output signals at the facets of adjacent manipulation waveguides. In these cases, when the phase tuner 290 is absent or present but not operated to add a phase difference, LIDAR output signals of different wavelengths can travel to the sample region along the same optical path or along substantially the same optical path. When the LIDAR chip can... Figures 3A to 4 Construction, having a basis Figure 9C When the output component 126 is constructed and the phase tuner 290 is included on the output component 126, the phase tuner 290 can be operated such that there is no phase difference between the output signals at adjacent manipulator facets. The absence of a phase difference between the LIDAR output signals allows LIDAR output signals of different wavelengths to travel along the same optical path or substantially the same optical path to the sample region. As a result, multiple different LIDAR input signals are generated for the same sample region, and each different LIDAR input signal is associated with a different wavelength. Therefore, there is an option to generate multiple LIDAR data values ​​for the sample region, where each LIDAR data value is associated with a different wavelength.

[0169] Figure 14 The LIDAR chip can be configured to manipulate the LIDAR output signal. For example, the LIDAR chip can be used according to... Figure 9C The output component 126 and / or the output component 126 are constructed and / or used Figure 10 The actuator is constructed using the context disclosed in the diagram. As a result, the electronics 62 can manipulate the LIDAR output signal from one sample region in the field of view to other sample regions in the field of view.

[0170] A LIDAR system can be configured to provide polarization diversity, where multiple sample regions in the field of view are simultaneously illuminated by multiple different LIDAR output signals, each with a different polarization. For example, Figure 15 The illustration shows a LiDAR chip 300 that outputs multiple LiDAR output signals, each with a different polarization. The first LiDAR output signal is labeled P1 and illustrated by a dashed line, and the second LiDAR output signal is labeled P2 and illustrated by a solid line. The first LiDAR output signal (P1) and the second LiDAR output signal (P2) can have the same wavelength. The LiDAR output signals are directed towards the same sample region. The sample region is located between the LiDAR output signals with sufficient overlap so that the LiDAR data in each output signal represents the same area of ​​the field of view. Figure 15The reflective object 304 located in the sample area is shown. As a result, the LIDAR output signal is shown as being reflected back from the field of view toward the LIDAR chip.

[0171] Different LIDAR output signals can completely or partially overlap, such as Figure 15 As shown in the diagram. However, different LIDAR output signals can travel away from the LIDAR chip in the same or substantially the same direction. As a result, different LIDAR output signals can be directed along the same or substantially the same optical path between the LIDAR chip 300 and the sample area, and therefore along the same optical path between the LIDAR chip and the reflective object located in the sample area. For example, the LIDAR chip can be directed according to... Figure 4 Construction, based on Figure 9C Output component 126 for construction and operation. According to... Figure 4 The constructed LIDAR chip may include a polarization rotator 294 positioned along a practical waveguide. When the light source 110 outputs a polarized outgoing optical signal, the polarization rotator 294 can change the polarization of the outgoing optical signal. For example, when the outgoing optical signal has a first polarization, the polarization rotator 294 can operate on the outgoing optical signal, so that the outgoing optical signal output by the polarization rotator 294 has a mixture of light in the first and second polarizations. As an example, when the outgoing optical signal has a first linear polarization, the polarization rotator 294 can operate on the outgoing optical signal, so that the outgoing optical signal output by the polarization rotator 294 has a mixture of light in the first and second linear polarizations. In some cases, the polarization rotator 294 is configured to output an outgoing optical signal in which 40-60% of the optical power is in the first linear polarization and 40-60% of the optical power is in the second linear polarization. In this configuration, the first and second LIDAR output signals have the same wavelength, and the first LIDAR output signal has a first linear polarization, while the second LIDAR output signal has a second linear polarization. Because the first and second LIDAR output signals have the same wavelength, they can be guided along the same or substantially the same optical path between the LIDAR chip and the sample area, and therefore along the same optical path between the LIDAR chip and the reflective object located in the sample area. As a result, multiple different LIDAR input signals are generated for the same sample area, and each different LIDAR input signal is associated with a different polarization. Therefore, there is an option to generate multiple LIDAR data values ​​for the sample area, where each LIDAR data value is associated with a different polarization.

[0172] As from Figures 12 to 15It is evident that a series of sample regions within the field of view can be simultaneously illuminated by multiple LiDAR output signals, which possess optical diversity selected from a group consisting of incident angle diversity, wavelength diversity, and polarization diversity. However, LiDAR output signals can have more than one optical diversity. For example, Figure 15 The LIDAR output signal can have both different wavelengths and different polarities. As another example, Figure 12 and Figure 13 The LIDAR output signals can have different wavelengths and different incident angles. Therefore, a series of sample regions in the field of view can each be simultaneously illuminated by multiple LIDAR output signals, which have one or more optical diversity selected from a group consisting of incident angle diversity, wavelength diversity, and polarization diversity.

[0173] Figure 15 The LIDAR chip can be configured to manipulate the LIDAR output signal. For example, the LIDAR chip can be used according to... Figure 9C The output component 126 and / or the output component 126 are constructed and / or used Figure 10 The actuator is constructed using the context disclosed in the diagram. As a result, the electronics 62 can manipulate the LIDAR output signal from one sample region in the field of view to other sample regions in the field of view.

[0174] Figures 12 to 15 The illustration shows different LiDAR output signals being collimated. However, in many cases, it is desirable for the different LiDAR output signals to have other optical properties. For example, it may be desirable for the LiDAR output signal to be focused. When focusing the LiDAR output signal causes the diameter of the LiDAR output signal at the reflecting object to be smaller than the diameter when it leaves the LiDAR system, focusing the LiDAR output signal can provide further performance improvements regarding speckle. The desired optical properties of the LiDAR output signal can be achieved using various different mechanisms. For example, one or more lenses can be used to achieve the desired optical properties. For example, a convex lens 314 can be used to collimate the LiDAR output signal, such as... Figure 12 As shown in the diagram. Alternatively, the distance between the lens and the LIDAR chip can be adjusted to focus the LIDAR output signal. When the LIDAR chip includes... Figure 9C When constructing the output component 126, one or more lenses can be used to achieve the desired optical characteristics. Alternatively, when the LIDAR chip includes... Figure 9CWhen the output component 126 is constructed and includes a phase tuner 290, the electronics can operate the phase tuner 290 to add collimation or focus to the LIDAR output signal. As a result, the electronics can operate the phase tuner 290 to provide the LIDAR output signal with desired optical characteristics and a desired manipulation direction. When the LIDAR chip includes... Figure 9C When the output component 126 is constructed and does not include the phase tuner 290, the first reference waveguide 210 and the second reference waveguide 208 can be configured to provide a phase shift between the output signals, which provides the desired optical characteristics for the LIDAR output signal.

[0175] As noted above, different LiDAR output signals are simultaneously incident on the same sample area in the field of view. These different LiDAR output signals incident on the same sample area may overlap. In some cases, the LiDAR output signals are configured such that if the LiDAR output signals do not intersect with the reflecting object, they will overlap with each other in the sample area, such that the minimum amount by which any one LiDAR output signal overlaps with another LiDAR output signal in the same area is greater than 25%, 45%, or 60% and less than or equal to 100% of the spot size of the overlapping LiDAR output signals in the field of view.

[0176] As noted above, each distinct optical diversity provides the opportunity to generate LiDAR data for a sample region using more than one LiDAR output signal. Therefore, in a single cycle, the LiDAR system has the capability to generate multiple distinct LiDAR data sets, each associated with a different LiDAR output signal. LiDAR data processing methods can be used to generate synthetic LiDAR data for a sample region during a single cycle. The synthetic LiDAR data can be LiDAR data considered as the distance and / or radial velocity between the LiDAR output signal source and the reflecting object, for further processing by electronics 62 and / or by other electronics communicating with electronics 62.

[0177] LIDAR data processing methods can generate synthetic LIDAR data based on combinations of different LIDAR data generated for a sample region during a single cycle. For example, the LIDAR data processing method can average, perform a weighted average, take the maximum, minimum, or median of different LIDAR data values ​​generated for the sample region during a single cycle. An example of a weighted average is the averaging of LIDAR data, where each LIDAR data point is weighted by the power of the LIDAR input signal from which it was generated. As an example, multiple radial velocity values ​​generated for a sample region during the same cycle can be averaged to generate a final radial velocity value. Alternatively, the LIDAR data processing method can identify specific LIDAR data to serve as synthetic LIDAR data. For example, the median LIDAR data value can be identified to serve as synthetic LIDAR data, or one or more selection criteria can be used to identify LIDAR data. Alternatively, one or more selection criteria can be used to identify specific LIDAR data, and the identified LIDAR data can be combined to generate synthetic LIDAR data. For example, the identified LIDAR data can be averaged. As an example, multiple radial distance values ​​identified can be averaged to generate a final radial velocity value.

[0178] An example of selecting a standard considers data indicating the power of a LiDAR input signal generated by the LiDAR output signal illuminating a sample region. Various indications of this power level are available from the LiDAR chip. For example, the output power from a balance detector, the output power from a light sensor that replaces the balance detector, the power of one or more signals with beats between the comparison signal and the reference signal, and the power of one or more signals with beats between a portion of the comparison signal and a portion of the reference signal can all indicate the power level of the LiDAR input signal. LiDAR data generated based on the strongest LiDAR input signal can be selected as the synthetic LiDAR data. Alternatively, one or more LiDAR input signals with power levels above a power threshold can be identified as the LiDAR input signals from which synthetic LiDAR data is generated. As noted above, the identified LiDAR data can be combined to generate synthetic LiDAR data. For example, the identified LiDAR data can be averaged. As an example, multiple identified radial distance values ​​can be averaged to generate a final radial velocity value.

[0179] Various platforms can be used for chips that include component assemblies. Suitable platforms include, but are not limited to, silicon-on-insulator (SiI) wafers. One or more of the aforementioned components and / or portions of the aforementioned components can be integrated with the chip, or can be placed on the chip using techniques such as flip-chip bonding. For example, light source 110 and / or photon source 111 may include gain elements and one or more other components, such as waveguides. Waveguides can be integrated with the chip, and gain elements can be components that are separate from the chip but attached to the chip using flip-chip bonding. Alternatively, the aforementioned LIDAR system can be constructed using discrete components. For example, all or part of the waveguides can be optical fibers connecting the discrete components. Alternatively, one or more portions of the LIDAR system can be integrated on the chip, while other portions are discrete components. For example, utility waveguide 16 can be or include optical fibers that provide optical communication between light source 110 and an optical chip that includes the rest of the LIDAR system.

[0180] In view of these teachings, other embodiments, combinations, and modifications of the invention will readily occur to those skilled in the art. Therefore, the invention will be limited only to the following claims, which, when viewed in conjunction with the foregoing description and drawings, encompass all such embodiments and modifications.

Claims

1. A LIDAR system, comprising: one or more LIDAR chips that generate a plurality of LIDAR output signals; and electronics that operate the one or more LIDAR chips such that LIDAR output signals are simultaneously directed at and overlap at a same sample region in a field of view, the LIDAR output signals having one or more optical diversities selected from the group consisting of wavelength diversity, polarization diversity, and diversity of angle of incidence of the LIDAR output signals relative to the sample region; the electronics generating a plurality of different LIDAR data results for the sample region, each of the LIDAR data results including a distance and / or radial velocity between the LIDAR system and the sample region; and each of the different LIDAR data results being associated with a different one of the LIDAR output signals, wherein the electronics generate the LIDAR data result using light from the LIDAR output signal associated with the LIDAR data result.

2. The LIDAR system of claim 1, wherein the one or more LIDAR chips is one LIDAR chip that generates the plurality of LIDAR output signals.

3. The LIDAR system of claim 1, wherein the one or more LIDAR chips is a plurality of LIDAR chips that generate the plurality of LIDAR output signals. the optical diversity is wavelength diversity.

4. The LIDAR system of claim 1, wherein, the optical diversity is polarization diversity.

5. The LIDAR system of claim 1, wherein, the optical diversity is diversity of angle of incidence.

6. The LIDAR system of claim 1, wherein, the sample region is one of a plurality of sample regions in the field of view, the electronics being configured to sequentially direct LIDAR output signals at a series of sample regions such that LIDAR output signals are simultaneously directed at and overlap at each of the sample regions.

7. The LIDAR system of claim 1, wherein, 8. The LIDAR system of claim 1, wherein the LIDAR output signals have more than one optical diversity. the LIDAR output signals travel to a focal point as each LIDAR output signal travels away from the LIDAR system.

9. The LIDAR system of claim 1, wherein, 10. A method of operating a LIDAR system, comprising: generating a plurality of LIDAR output signals; simultaneously directing the LIDAR output signals at a sample region in a field of view such that the LIDAR output signals have one or more optical diversities selected from the group consisting of wavelength diversity, polarization diversity, and diversity of angle of incidence of the LIDAR output signals relative to the sample region; generating a plurality of different LIDAR data results for the sample region, each of the LIDAR data results including a distance and / or radial velocity between the LIDAR system and the sample region; and each of the different LIDAR data results being associated with a different one of the LIDAR output signals, wherein the electronics generate the LIDAR data result using light from the LIDAR output signal associated with the LIDAR data result. the LIDAR output signals exit from a LIDAR chip.

11. The method of claim 10, wherein, ​ 12. The method of claim 10, wherein, The LIDAR output signals exit from different LIDAR chips.

13. The method of claim 10, wherein, The optical diversity is wavelength diversity.

14. The method of claim 10, wherein, The optical diversity is polarization diversity.

15. The method of claim 10, wherein, The optical diversity is incidence angle diversity.

16. The method of claim 10, wherein, The sample region is one of a plurality of sample regions in a field of view, and further comprises: The LIDAR output signals are directed sequentially to a series of sample regions such that the LIDAR output signals are directed to multiple sample regions in the series simultaneously and overlap at each of the sample regions.

17. The method of claim 10, wherein, The LIDAR output signals have more than one optical diversity.

18. The method of claim 10, wherein, The LIDAR output signals travel to a focal point as each LIDAR output signal travels to a sample region.

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