Polarizing optical device for coherent lidar

Abstract

The invention relates to a polarizing optical device for coherent LIDAR. In some implementations, an optical system for LIDAR sensing includes an emitter configured to emit a light beam; a polarization beam splitter configured to block a first polarized emission component of the light beam and to pass a second polarized emission component of the light beam; a wave plate configured to convert a second polarized emission component of the light beam to a circularly polarized state and to direct the light beam toward a target, where the wave plate is configured to receive a return reflection of the light beam and to convert the return reflection to a second polarized reflection component, and wherein the polarizing beam splitter is configured to reflect the second polarized reflected component and to pass the first polarized reflected component that is reflected back; a linear polarizer configured to pass the second polarized reflection component; and a coherent receiver configured to receive return reflections from the linear polarizer.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This patent application claims priority to U.S. Provisional Patent Application No. 63 / 590,640, filed on October 16, 2023, entitled “PRECISION COHERENTLIDAR USING POLARIZING OPTICS.” The disclosure of the prior application is considered a part of this patent application and is incorporated by reference into this patent application. Technical Field

[0003] The present disclosure relates generally to polarization optics and polarization optics for coherent light detection and ranging (LIDAR). Background Art

[0004] LIDAR (sometimes referred to as "light detection and ranging") can be used for a variety of applications, such as generating high-resolution maps, controlling autonomous vehicles, analyzing objects, three-dimensional sensing, gesture recognition, etc. For example, an electro-optical system including a LIDAR sensor can detect, analyze, and / or measure the distance to a target by illuminating the target with a pulsed laser and analyzing the reflected pulses. The LIDAR sensor provides LIDAR data based on the difference in pulse emission and return times (e.g., time of flight (TOF)) and / or the difference in pulse wavelengths associated with points on the target. Such LIDAR data can be used to determine a representation of a target, features of a target, and / or the distance to features of a target. Summary of the invention

[0005] In some implementations, an optical system for LIDAR sensing includes a transmitter configured to transmit an amplitude modulated light beam; a polarization beam splitter configured to block a first polarization emission component of the light beam and pass a second polarization emission component of the light beam; a wave plate configured to convert the second polarization emission component of the light beam into a circular polarization state and direct the light beam toward a target, wherein the wave plate is configured to receive a return reflection of the light beam and convert the return reflection of the light beam into a second polarization reflection component, and wherein the polarization beam splitter is configured to reflect the second polarization reflection component and pass a first polarization reflection component of the return reflection of the light beam; a linear polarizer configured to pass the second polarization reflection component; and a coherent receiver configured to receive the return reflection of the light beam from the linear polarizer.

[0006] In some implementations, an optical system includes a polarizing beam splitter; a wave plate; a linear polarizer; a coherent receiver; and a transmitter for emitting an amplitude modulated light beam along an optical path, wherein the optical path extends toward a target through the polarizing beam splitter and the wave plate, extends back through the wave plate, is reflected by the polarizing beam splitter, and extends through the linear polarizer to the coherent receiver.

[0007] In some implementations, a method includes transmitting, by a transmitter of an electro-optical system, a light beam through a collection of optical devices, wherein the collection of optical devices includes: a polarization beam splitter configured to block a first polarization emission component of the light beam and pass a second polarization emission component of the light beam; a wave plate configured to convert the second polarization emission component of the light beam into a circular polarization state and direct the light beam toward a target, wherein the wave plate is configured to receive a reflection of the light beam and convert a return reflection of the light beam into a second polarization reflection component, and wherein the polarization beam splitter is configured to reflect the second polarization reflection component and pass a first polarization reflection component of the return reflection of the light beam; and a linear polarizer configured to pass the second polarization reflection component; and receiving, by a receiver of the electro-optical system, the return reflection of the light beam from the linear polarizer; generating, by a controller of the electro-optical system, a LIDAR measurement result of the target using an output of the receiver corresponding to the return reflection of the light beam; and outputting, by an output component of the electro-optical system, information identifying the LIDAR measurement result. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 is a diagram of an example optical system associated with polarization optics for coherent LIDAR.

[0009] Figure 2 is a diagram of an example electro-optical system associated with LIDAR measurements using polarization optics.

[0010] Figure 3A-3C is a diagram of an example associated with LIDAR measurements using polarization optics.

[0011] Figure 4 is a flow chart of an example process associated with polarization optics for coherent LIDAR. DETAILED DESCRIPTION

[0012] The following detailed description of example implementations refers to the accompanying drawings.The same reference numbers in different drawings may identify the same or similar elements.

[0013] Electro-optical systems can be used for communication, measurement, imaging, gesture recognition, object recognition, three-dimensional sensing, etc. For example, a LIDAR system can be used to determine the distance between the emitter of the LIDAR system and a target (such as an object, a geographic area, or a person) (e.g., for gesture recognition). By combining many distance measurements of the target, the LIDAR system can generate a three-dimensional representation of the target. In one use case, the LIDAR system can be integrated into a production line to perform automatic inspection of manufactured products. For example, the LIDAR system can generate a three-dimensional representation of the manufactured product and use the three-dimensional representation to control an automated process (e.g., for controlling a robotic arm or a pick-and-place machine) or for quality control. In such a use case, as an example, the LIDAR system can image the target at a high sampling rate. Since the amount of time allocated to product manufacturing may be limited, a single sensor that can only process 1000 samples per second will limit the number of features, products, and / or areas of interest that a single sensor can measure. In another use case, the LIDAR system can be integrated into an autonomous vehicle to perform object recognition to enable autonomous control of the autonomous vehicle. For example, a LIDAR system may generate a three-dimensional representation of the area surrounding a vehicle and use the three-dimensional representation for collision avoidance or object identification. In such a use case, as an example, a LIDAR system may image targets at relatively long distances (e.g., to ensure that the LIDAR image processing and system control have sufficient time to respond to detected objects). Because the amount of light returning to the sensor is related to the distance of the object, objects located more than a few meters away require a highly sensitive detector that may also be highly sensitive to sources of optical noise (e.g., which may reduce measurement precision and / or accuracy).

[0014] One type of LIDAR system that can be used for LIDAR measurements is a pulsed LIDAR system. In a pulsed LIDAR system, the LIDAR system transmits a light pulse of a configured length at a configured frequency, and measures the response of the pulse. However, some frequencies that can be used for pulsed LIDAR systems with high sampling rates are limited by power limitations associated with ensuring eye safety and precision and / or accuracy associated with pulse length. At other frequencies, with reduced eye safety risks, pulsed LIDAR systems can achieve higher powers and associated longer distances, but may have relatively slower sampling rates and relatively lower insensitivity to optical noise.

[0015] Another type of LIDAR system that can be used for LIDAR measurement is based on the technology of coherent frequency modulated continuous wave (FMCW) LIDAR. FMCW LIDAR can use coherent continuous wave laser to improve the optical noise insensitivity relative to direct detection using pulsed LIDAR, including optical noise from other light sources (e.g., sun glare, incandescent light, or other LIDAR systems). In addition, LIDAR systems using coherent light can avoid eye hazards associated with high peak power. However, FMCW LIDAR can also have a relatively low sampling rate, which may hinder integration into production lines, for example. Another type of LIDAR system that can be used for LIDAR measurement is based on the technology of amplitude modulated continuous wave (AMCW). AMCW LIDAR can use coherent continuous wave lasers with amplitude modulation to achieve high sampling rate, high measurement accuracy and high insensitivity to some optical noise sources (e.g., sun glare, incandescent light, other LIDAR systems). However, due to object transparency, the presence of multiple surfaces, and the configuration of the AMCW LIDAR system's receiver (eg, sensor), the AMCW LIDAR system may have difficulty distinguishing phases at different distances.

[0016] Some implementations described herein provide polarization optical devices for reducing signal interference in precision coherent LIDAR systems. For example, an optical system for LIDAR sensing (such as an AMCW LIDAR system) may include a set of optical components, such as a high extinction ratio linear polarizer, a polarization beam splitter, or a wave plate, etc., which are arranged in the optical path to reduce signal interference. By including a set of optical components in the optical path, the optical system achieves, for example, an extinction of at least 3000:1, thereby improving the LIDAR distance measurement accuracy and range by solving errors associated with back reflections of other optical devices of the optical system. In addition, the optical component set maintains a fixed polarization between the transmitter and the receiver, thereby improving the distance measurement associated with a higher signal from a target, object, or material that does not completely depolarize the light when reflected. In some implementations, the optical system may include a liquid crystal wave plate designed into an optical shell window. By using a liquid crystal wave plate, the optical system may be able to provide a larger viewing angle for optical sensing, thereby improving optical sensing performance.

[0017] Figure 1 is a schematic diagram of an example optical system 100 associated with polarization optics for coherent LIDAR. Figure 1As shown, the optical system 100 may include a transmitter 110, a receiver 120, and a set of polarization optical components, wherein the polarization optical components may include a polarization beam splitter 130, a wave plate 140, and a linear polarizer 150. In some implementations, the polarization beam splitter 130 and the linear polarizer 150 may be integrated into a single optical component or package. For example, the optical system 100 may include a linear polarizer with a polarization beam splitter (LP-PBS), which may include both a linear polarizer and a polarization beam splitter disposed on a common substrate or in a common package. In some implementations, the optical system 100 may include one or more other optical elements 160.

[0018] like Figure 1 As further shown, the transmitter 110, the receiver 120, the set of polarization optical components (e.g., polarization beam splitter 130, wave plate 140, and linear polarizer 150), and one or more other optical elements 160 can be aligned along an optical path 170. For example, as shown, the optical transmitter 110 can transmit a light beam in a first polarization state (such as a p-polarization state) through the polarization beam splitter 130 along the optical path 170. The light beam passes through the one or more other optical elements 160 along the optical path 170 and reaches the wave plate 140. The wave plate 140 can convert the light beam to a circular polarization state and can direct the light beam toward a target 180 along the optical path 170. In some implementations, the wave plate 140 can include a quarter wave plate (QWP) that is disposed at a configuration angle relative to the electric field of the first polarization state in the optical path 170, such as a 45 degree angle. The light beam can be backscattered by the target 180 and can be reflected back along the optical path 170 toward the wave plate 140 as a reflected light beam.

[0019] The wave plate 140 can rotate the reflected light beam to a second polarization state, such as the s-polarization state shown, and direct the reflected light beam along the optical path 170 toward one or more other optical elements 160. In other words, although some implementations are described herein in terms of p-polarization state and s-polarization state, other polarization states are also contemplated. For example, instead of passing the s-polarization state to the receiver 120 and blocking the p-polarization state as described herein, the p-polarization state can be passed to the receiver 120 and the s-polarization state can be blocked.

[0020] The reflected light beam travels along optical path 170 to polarizing beam splitter 130. In this case, based on the reflected light beam being in the s-polarization state, polarizing beam splitter 130 reflects the reflected light beam along optical path 170 toward linear polarizer 150. In some implementations, a portion of the reflected light beam may maintain the p-polarization state. For example, based on wave plate 140 converting the reflected light beam from a circular polarization state to an s-polarization state, some of the reflected light beam propagating to polarizing beam splitter 130 may be in the p-polarization state.

[0021] The position of wave plate 140 relative to the other optical elements 160 reduces the amount of undesirable interference at the receiver. If wave plate 140 were placed before the other optical elements 160, the result could be that the back reflection from optical element 160 would be returned in the s-polarization state instead of the p-polarization state, thereby interfering with the reflection from target 180, which is also in the s-polarization state. Therefore, the position of wave plate 140 after optical element 160 causes the back reflection from optical element 160 to be in the p-polarization state, which is removed from the reflected beam by polarizing beam splitter 130 and linear polarizer 150 to reduce the possibility of interference.

[0022] The polarization beam splitter 130 ensures that a high polarization extinction ratio beam is emitted to reduce the amount of interference at the receiver. In some implementations, the emission beam may include a portion of light that remains in the s polarization state rather than the p polarization state (e.g., due to defects in the polarization state generated by the polarization beam splitter). For example, the emission beam may include p polarized light and s polarized light (e.g., because the polarization beam splitter cannot completely remove the s polarized light). When the one or more optical elements 160 receive the p polarized beam (e.g., received from the transmitter 110 and the polarization beam splitter 130 before the beam is incident on the target 180), as described above, the one or more optical elements 160 may pass the beam toward the wave plate 140 and may reflect some of the beam back toward the polarization beam splitter 130. In this case, the reverse reflected portion of the beam from the optical element in the p polarization state (e.g., the return reflection) may have some light in the s polarization state, which may interfere with the beam reflected from the target 180. Therefore, the polarization beam splitter 130 can reduce interference at the receiver 120 by ensuring a high extinction ratio toward the optical element 160.

[0023] The polarization beam splitter 130 and the linear polarizer 150 can reduce the amount of interference at the receiver 120 by removing p-polarization state light directed toward the receiver. In some implementations, the reflected light beam can include light in the p-polarization state, which can cause interference at the receiver 120 (e.g., due to defects in the polarization state generated by the polarization beam splitter 130 and / or the linear polarizer 150 that allow a portion of the p-polarization to reach the receiver 120). In this case, when the optical element 160 returns the p-polarization state light toward the polarization beam splitter 130 and the linear polarizer 150, a portion of the p-polarized light beam is passed onto the receiver 120 and can interfere with the reflected light beam from the target 180. Additionally or alternatively, the reflected light beam may include light in the p-polarization state due to the introduction of interfering light from another source (e.g., sun glare, a light bulb, or another LIDAR system). Additionally or alternatively, light that is converted from s-polarization to p-polarization due to multiple reflection events at the target 180 may cause interference due to the additional distance from each reflection.

[0024] Based on the polarization beam splitter 130 receiving the reflected light beam, the polarization beam splitter 130 allows the portion of the reflected light beam in the p-polarization state to pass through without reflecting the portion of the reflected light beam in the p-polarization state. For example, the polarization beam splitter 130 can allow the portion of the reflected light beam in the p-polarization state to pass through, instead of reflecting the portion of the reflected light beam in the p-polarization state like the above-mentioned portion of the reflected light beam in the s-polarization state. In this way, the polarization beam splitter 130 reduces the possibility of interfering p-polarization state light being incident on the receiver 120. In some implementations, an isolator (not shown) or another optical element can be positioned between the transmitter 110 and the polarization beam splitter 130 to absorb the portion of the reflected light beam in the p-polarization state, thereby preventing the portion of the reflected light beam in the p-polarization state from being incident on the transmitter 110.

[0025] The linear polarizer 150 receives the reflected light beam in the s-polarization state and passes the reflected light beam in the s-polarization state toward the receiver 120. In some implementations, a portion of the reflected light beam received from the polarization beam splitter is in the p-polarization state instead of the s-polarization state. For example, due to the incomplete polarization state selectivity of the polarization beam splitter 130, some light in the p-polarization state may be reflected by the polarization beam splitter 130 toward the receiver 120 instead of passing through (e.g., toward the transmitter 110 and the isolator, as described above). Additionally or alternatively, other interference sources (e.g., other optical devices or external sources) may cause some p-polarization state interference light to be directed toward the linear polarizer 150. In these cases, the linear polarizer 150 blocks the portion of the reflected light beam in the p-polarization state (e.g., the portion that has been reflected by the polarization beam splitter 130 toward the receiver 120).

[0026] In another configuration, the elements of optical system 100 may be arranged in another order. For example, the positions of linear polarizer 150 and polarizing beam splitter 130 may be swapped so that transmitter 110 directs a light beam in an s-polarization state toward linear polarizer 150 and polarizing beam splitter 130, and the light beam is directed from polarizing beam splitter 130 toward target 180. In this case, a reflection of the light beam is directed back to polarizing beam splitter 130, and the reflected p-polarized portion of the light beam is passed to receiver 120 (e.g., without further passing through linear polarizer 150).

[0027] The receiver 120 receives the remaining portion of the reflected light beam that is not blocked by the linear polarizer 150. For example, the receiver 120 receives the reflected light beam in the s-polarization state based on the polarization beam splitter 130 and the linear polarizer 150, and the portion of the reflected light beam in the p-polarization state is blocked. In some implementations, the receiver 120 may be a coherent receiver (e.g., an optical hybrid detector). For example, the receiver 120 may combine local light from a local oscillator (e.g., a tap from the transmitter 110) with signal light (e.g., the remaining portion of the reflected light beam used to perform the measurement). In this case, the optical system 100 may include a beam splitting component to split the light beam into a sample path (e.g., which is directed toward the target 180 and is reflected back toward the receiver 120) and a local oscillator path (e.g., which is directed toward the receiver 120 without being reflected by the target 180). The receiver 120 may convert the optical in-phase (I) and quadrature-phase (Q) components of the return reflection of the light beam into analog signals.

[0028] The receiver 120 may perform measurements on the received reflected light beams, and a controller (not shown) may use the measurements to perform determinations. For example, the controller may use LIDAR measurements, time of flight measurements, amplitude measurements, etc. to perform point cloud determinations of the target 180, object recognition of the target 180, gesture recognition of the target 180, or three-dimensional sensing determinations of the target 180, as examples. In some implementations, the optical system 100 may generate measurements of the target 180 or determinations related to the target 180 with a particular accuracy based on the presence of the polarization beam splitter 130, the wave plate 140, and / or the linear polarizer 150. For example, based on achieving an extinction ratio of, for example, at least 3000:1, the receiver 120 may have, for example, a noise floor reduced by up to 35 decibels (dB), thereby improving the accuracy of the measurements performed by the receiver 120 and eliminating the possibility of artifacts that may be detrimental to the measurements.

[0029] As mentioned above, Figure 1 Other examples can be found in the Figure 1 Different from what is described. Figure 1 The number and arrangement of the devices shown are provided as examples only. Figure 1 There may be more devices, fewer devices, different devices, or differently arranged devices than shown. Figure 1 Two or more of the devices shown may be implemented in a single device, or Figure 1 The single device shown may be implemented as multiple distributed devices. Alternatively or additionally, Figure 1 The illustrated set of devices (e.g., one or more devices) may perform the operations described as being performed by Figure 1 Another group of devices is shown performing one or more functions.

[0030] Figure 2 is a schematic diagram of an example electro-optical system 200 associated with LIDAR measurements using polarization optics. Figure 2 As shown, the electro-optical system 200 may include an analog coherent optical device (ACO) 202, a collection of LC / UPC fiber connectors 204, a polarization-maintaining erbium-doped fiber array (PM-EDFA) 206, a collimating lens 208, a polarization beam splitter 210, an adjustable focusing assembly 212, an objective lens 214, a wave plate 216, a collection of mirrors 218 aligned with a target 220 (e.g., a sample), a coupling lens 222, a fiber end 224, a polarization controller 226, a field programmable gate array (FPGA) system 228, a personal computer (PC) 230, a clock 232, an RF synthesizer 234, and an RF combiner assembly 236.

[0031] One or more synthesizers 234 can generate electrical signals associated with a radio frequency (RF) pattern to be transmitted toward the target 220. For example, a set of RF synthesizers 234 can generate electrical signals for a set of three sinusoidal tones of an RF signal and transmit the electrical signals to the FPGA system 228 for digitization. The RF combiner component 236 can encode the RF signal on an optical carrier using a Mach-Zehnder (MZ) modulator (MZM) and cause the ACO 202 to transmit the optical signal encoded with the RF signal. The clock 232 can generate a clock signal that synchronizes the one or more RF synthesizers 234 with the digitizer of the FPGA system 228.

[0032] The ACO 202 and the LC / UPC connector 204-1 can transmit an output optical signal via a light beam along a PM optical fiber toward a PM-EDFA 206. The PM-EDFA 206 can amplify the optical signal and transmit the light beam along the PM optical fiber toward a collimating lens 208. The collimating lens 208 can collimate the light beam and transmit the light beam toward a polarizing beam splitter 210 via free space. The polarizing beam splitter 210 can pass a light beam (e.g., a light beam in a p-polarization state) and transmit the light beam toward an adjustable focus assembly 212 via free space. The adjustable focus assembly 212 can include one or more lenses to focus the light beam and direct the light beam toward an objective lens 214. A beam expander including the adjustable focus assembly 212 and the objective lens 214 can expand the light beam and direct the light beam toward a wave plate 216, which can be a quarter wave plate. The wave plate 216 can rotate the light beam to a circular polarization state and direct the light beam toward a reflector set 218. Mirror set 218 may include a two-dimensional galvo mirror set that can scan a light beam over target 220 to obtain one or more back reflections from portions of target sample 220 (eg, thereby generating a point cloud or other representation of target 220 ).

[0033] The reflected light beam (e.g., reflected by the target 220) is directed through the wave plate 216 (e.g., via the reflector set 218). The wave plate 216 rotates the polarization state of the reflected light beam to the s polarization state. The amount of loss associated with the rotation to the s polarization state by the wave plate 216 can be less than 0.1 dB. The wave plate 216 directs the reflected light beam to the polarization beam splitter 210 (e.g., via the beam expander of the adjustable focusing assembly 212 and the objective lens 214 in free space), which reflects the s polarization state component of the reflected light beam and passes the remaining p polarization state component of the reflected light beam (e.g., to be extinguished via an isolator (not shown)). The reflected light beam (e.g., in the s polarization state) is directed to the coupling lens 222, which focuses the reflected light beam onto the optical fiber end 224. The optical fiber end 224 directs the reflected light beam along a polarization-maintaining (PM) fiber or a single-mode (SM) fiber toward a polarization controller 226, which may include a linear polarizer or another polarization control component as described above to pass the s-polarization state component of the reflected light beam and block the p-polarization state component of the reflected light beam. The polarization controller 226 directs the reflected light beam toward the LC / UPC connector 204-2 of the ACO 202, where the reflected light beam is detected by a detector in the ACO 202.

[0034] The detector of ACO 202 can convert the RF pattern on the light beam into an electrical signal for sampling by FPGA system 228 and / or PC 230, such as the in-phase component (XI) and the quadrature component (XQ) of the light beam to determine the measurement of the target, where X is the polarization state. The electro-optical system 200 (e.g., using FPGA 228 and / or PC 230) can calculate the time of flight measurement, velocity measurement, distance measurement, or other measurement of the target 220. In some implementations, the electro-optical system 200 can use a square sum method applied to different optical receiver channels (e.g., three signals modulated onto the light beam) to stabilize the amplitude of the RF power of the reflected light beam and account for optical phase shifts. The electro-optical system 200 can use a set of measurements of the target 220 (e.g., based on the set of reflectors 218 that scan the light beam over the target 220) to generate a three-dimensional point cloud image representing the target 220. Based on the generation of the three-dimensional point cloud image, the electro-optical system 200 can generate a control signal (e.g., for controlling a quality control production line or for controlling an autonomous vehicle).

[0035] As mentioned above, Figure 2 Other examples can be found in the Figure 2 Different from what is described. Figure 2 The number and arrangement of the devices shown are provided as examples only. Figure 2 There may be more devices, fewer devices, different devices, or differently arranged devices than shown. Figure 2 Two or more of the devices shown may be implemented in a single device, or Figure 2 The single device shown may be implemented as multiple distributed devices. Alternatively or additionally, Figure 2 The illustrated set of devices (e.g., one or more devices) may perform the operations described as being performed by Figure 2 Another group of devices is shown performing one or more functions.

[0036] Figure 3A-3C is a diagram of an example 300 associated with LIDAR measurements using polarization optics.

[0037] Figure 3A An example of a target 300 for LIDAR measurement is shown. The target 300 may correspond to Figure 1 Target 180 or Figure 2 The target is 220. Figure 3B Point cloud 310 and graph 310a are shown for target 300 at a distance of about 2 meters using a first LIDAR measurement system that does not include a polarization beam combiner, wave plate, and / or linear polarizer in the configuration of optical system 100 or electro-optical system 200. Point cloud 310 is generated using an optical noise of -44 decibel milliwatts (dBm). Graph 310a illustrates a set of distance measurements corresponding to point cloud 310. In contrast, Figure 3C Point cloud 320 and graph 320a are shown generated for target 300 at a distance of about 2 meters using a second LIDAR measurement system including a polarization beam combiner, wave plate, and linear polarizer, such as optical system 100 or electro-optical system 200. Point cloud 320 was generated using an optical noise of -58 dBm. Graph 320a illustrates a set of distance measurements corresponding to point cloud 320. Point cloud 320 and graph 320a show a reduction in image artifacts relative to point cloud 310 and graph 310a, which is a result of the approximately 14 dB reduction in the noise floor and the resultant polarization provided by the polarization beam combiner, wave plate, and linear polarizer used to steer the beam.

[0038] As mentioned above, Figure 3A-3C Provided as an example only. Other examples may be found in Figure 3A-3C Different from what is described.

[0039] Figure 4 is a flow chart of an example process 400 associated with polarization optics for coherent LIDAR. In some implementations, Figure 4 One or more process blocks of are performed by an electro-optical system (e.g., electro-optical system 200). In some implementations, Figure 4One or more process blocks of are performed by another device or group of devices separate from or including the electro-optical system, such as an optical system (eg, optical system 100 ) or a component thereof.

[0040] like Figure 4 As shown, process 400 may include emitting a coherent light beam through a set of optical devices (block 410). For example, the electro-optical system may emit a coherent light beam through a set of optical devices, as described above. In some implementations, the coherent light beam may include an AM LIDAR type light beam having a pattern modulated onto the light beam, such as one or more sinusoidal patterns modulated onto the light beam. In some implementations, the set of optical devices may include a polarization beam splitter, a wave plate, and / or a linear polarizer to provide polarization selectivity for a particular polarization state. In some implementations, other optical devices included in the electro-optical system may include an optical relay assembly, an optical extension assembly, an optical focusing assembly, or an optical scanning assembly. In this case, the set of optical devices may block back reflections from other optical devices, thereby improving polarization selectivity and avoiding noise associated with back reflections.

[0041] like Figure 4 As further shown, process 400 may include receiving a reflection of the light beam through the optical device set (block 420). For example, as described above, the electro-optical system may receive a reflection of the light beam through the optical device set. The optical device set may rotate and control the polarization state of the reflection of the light beam so that a configured polarization state is incident on a receiver of the electro-optical system, while other polarization states are blocked from being incident on the receiver of the electro-optical system.

[0042] like Figure 4 As further shown, process 400 may include generating LIDAR measurements of the target corresponding to the reflection of the light beam (block 430). For example, as described above, the electro-optical system may generate LIDAR measurements of the target corresponding to the reflection of the light beam. In some implementations, the electro-optical system may generate a point cloud determination (e.g., a three-dimensional point cloud representation of the target), an object recognition result of the target, a gesture recognition result of the target, or a three-dimensional sensing determination of the target. In some implementations, the electro-optical system may output the LIDAR measurements of the target, and a separate system may use the output to generate a determination (e.g., a gesture recognition result) about the target.

[0043] like Figure 4As further shown, process 400 may include outputting information identifying the LIDAR measurements (block 440). For example, as described above, the electro-optical system may output information identifying the LIDAR measurements. In some implementations, the electro-optical system may output the LIDAR measurements, determinations regarding the LIDAR measurements, or control signals based on the LIDAR measurements or determinations regarding the LIDAR measurements.

[0044] Process 400 may include additional implementations, such as any single implementation or any combination of implementations described below and / or described in conjunction with one or more other processes described elsewhere herein.

[0045] In a first implementation, the information identifying the LIDAR measurements includes ranging information identifying a distance of the target from the electro-optical system.

[0046] In a second implementation, either alone or in combination with the first implementation, the information identifying the LIDAR measurement result includes at least one of a point cloud determination result associated with the target, an object recognition result of the target, a gesture recognition result of the target, or a three-dimensional sensing determination result associated with the target.

[0047] although Figure 4 An example block diagram of process 400 is shown, but in some implementations, Figure 4 Process 400 includes more blocks, fewer blocks, different blocks, or differently arranged blocks than shown. Additionally or alternatively, two or more blocks of process 400 may be performed in parallel.

[0048] The above disclosure provides illustration and description, but is not intended to be exhaustive or to limit the implementation to the precise form disclosed. Modifications and variations may be made based on the above disclosure, or may be obtained from the practice of the implementation. In addition, any implementation described herein may be combined, unless the above disclosure explicitly provides reasons why one or more implementations cannot be combined.

[0049] As used herein, satisfying a threshold may refer to a value being greater than a threshold, greater than or equal to a threshold, less than a threshold, less than or equal to a threshold, equal to a threshold, not equal to a threshold, etc., depending on the context.

[0050] Although specific combinations of features are cited in the claims and / or disclosed in the specification, these combinations are not intended to limit the disclosure of various implementations. In fact, many of these features can be combined in a manner that is not specifically cited in the claims and / or not disclosed in the specification. Although each dependent claim listed below can only directly depend on one claim, the disclosure of various implementations includes the combination of each dependent claim with each other claim in the claim set. As used herein, the phrase "at least one" referring to a list of items refers to any combination of these items, including single members. For example, "at least one of a, b or c" is intended to cover a, b, c, ab, ac, bc and abc, and multiple combinations of the same items.

[0051] When a component or one or more components (e.g., a laser emitter or one or more laser emitters) is described or claimed (either within a single claim or across multiple claims) as performing multiple operations or being configured to perform multiple operations, such language is intended to broadly cover a variety of architectures and environments. For example, unless otherwise expressly required (e.g., by use of "a first component" and "a second component" or other language in the claim that distinguishes between components), the language is intended to cover a single component that performs or is configured to perform all of these operations, a group of components that collectively perform or are configured to perform all of these operations, a first component that performs or is configured to perform a first operation and a second component that performs or is configured to perform a second operation, or any combination of components that perform or are configured to perform these operations. For example, when a claim is of the form "One or more components are configured to: perform X; perform Y; and perform Z," the claim should be interpreted as "One or more components are configured to perform X; one or more (possibly different) components are configured to perform Y; and one or more (possibly different) components are configured to perform Z."

[0052] Unless explicitly stated, any element, behavior or indication used in this article should not be interpreted as critical or essential. In addition, as used in this article, the articles "one" and "an" are intended to include one or more items, and can be used interchangeably with "one or more". In addition, as used in the text, the article "said" is intended to include one or more items related to the article "said", and can be used interchangeably with "one or more". In addition, as used in this article, the word "set" is intended to include one or more items (for example, a combination of related items, unrelated items, or related and unrelated items), and can be used interchangeably with "one or more". If only one item is intended to be used, the phrase "only one" or similar language is used. In addition, as used in this article, the terms "have", "have", "contain" etc. are intended to become open terms. In addition, unless otherwise explicitly stated, the word "based on" is intended to mean "at least partially based on". In addition, as used in this article, the term "or" is intended to be inclusive when used in series, and can be used interchangeably with "and / or", unless otherwise explicitly stated (for example, if used in combination with "any one of ..." or "only one of ..."). Additionally, for ease of description, spatially relative terms (such as "below," "lower," "above," "upper," "left," "right," etc.) may be used herein to describe the relationship of one element or feature to another element or feature shown in the figures. Spatially relative terms are intended to encompass different orientations of the device, equipment, and / or elements in use or operation in addition to the orientation shown in the figures. The device may be otherwise oriented (rotated 90 degrees or at other orientations), and the spatially relative descriptors used herein may be interpreted accordingly.

Claims

1. An optical system for LIDAR sensing, comprising: a transmitter configured to transmit an amplitude modulated light beam; a polarization beam splitter configured to block a first polarization emission component of the light beam and pass a second polarization emission component of the light beam; a wave plate configured to convert the second polarized emission component of the light beam into a circular polarization state and direct the light beam toward a target, wherein the wave plate is configured to receive a return reflection of the light beam and convert the return reflection of the light beam into a second polarized reflection component, and wherein the polarization beam splitter is configured to reflect the second polarized reflection component and pass the return-reflected first polarized reflection component of the light beam; a linear polarizer configured to pass the second polarized reflected component; as well as A coherent receiver is configured to receive the return reflection of the light beam from the linear polarizer.

2. The optical system according to claim 1, further comprising: A beam splitting component is used to split the light beam into a sample path and a local oscillator path, The sample path is directed toward the polarizing beam splitter.

3. The optical system according to claim 1, further comprising: A Mach-Zehnder modulator is used to modulate the light beam and direct the light beam toward the polarizing beam splitter.

4. The optical system according to claim 1, further comprising: An amplifier assembly is provided for amplifying the light beam and directing the light beam toward the polarizing beam splitter. 5 . The optical system of claim 1 , wherein the coherent receiver is configured to detect the light beam and convert an optical in-phase component and an optical quadrature-phase component of the light beam into analog signals.

6. The optical system according to claim 1, further comprising: A coherent optical device is simulated for outputting the light beam along an optical fiber toward the polarization beam splitter.

7. The optical system of claim 6, wherein the simulated coherent optical device comprises at least one of the transmitter or the coherent receiver.

8. The optical system according to claim 1, further comprising: An erbium doped fiber array (EDFA) is used to amplify the light beam.

9. The optical system of claim 1, further comprising: A collection of lenses for collimating, expanding and focusing the light beam.

10. The optical system of claim 1, further comprising: A scanning assembly is used to scan the light beam across the target.

11. The optical system according to claim 1, further comprising: A time of flight determination component is configured to perform measurements associated with an output of the coherent receiver, the output corresponding to the light beam.

12. The optical system of claim 1, wherein the wave plate is a liquid crystal wave plate.

13. An optical system comprising: Polarization beam splitter; Wave plates; Linear polarizer; Coherent receiver; as well as a transmitter for transmitting an amplitude modulated light beam along an optical path, The light path extends through the polarizing beam splitter and the wave plate toward a target, extends back through the wave plate, is reflected by the polarizing beam splitter, and extends through the linear polarizer to the coherent receiver.

14. The optical system according to claim 13, further comprising: an isolator aligned between the transmitter and the polarizing beam splitter, Another optical path extends through the polarizing beam splitter and the wave plate, is reflected by the target, extends back through the wave plate, and extends through the polarizing beam splitter to the isolator.

15. The optical system of claim 13, further comprising: One or more optical components are disposed in the optical path between the polarizing beam splitter and the wave plate.

16. The optical system of claim 15, wherein the one or more optical components include at least one of the following: Optical relay components, Optical extension kit, Optical focusing components, or Optical scanning assembly.

17. The optical system of claim 13, wherein an extinction ratio of the optical system along the optical path is at least 3000:1 extinction for the configured polarization state.

18. A method comprising: The transmitter of the electro-optical system sends a light beam through a collection of optical devices. The optical device assembly comprises: a polarization beam splitter configured to block a first polarization emission component of the light beam and pass a second polarization emission component of the light beam; a wave plate configured to convert the second polarized emission component of the light beam into a circular polarization state and direct the light beam toward a target, wherein the wave plate is configured to receive a return reflection of the light beam and convert the return reflection of the light beam into a second polarized reflection component, and wherein the polarization beam splitter is configured to reflect the second polarized reflection component and to pass the return-reflected first polarized reflection component of the light beam; and a linear polarizer configured to pass the second polarized reflection component; and receiving, by a receiver of the electro-optical system, the return reflection of the light beam from the linear polarizer; generating, by a controller of the electro-optical system, a LIDAR measurement of the target using an output of the receiver corresponding to the return reflection of the light beam; and Information identifying the LIDAR measurement result is output by an output component of the electro-optical system.

19. The method of claim 18, wherein the information identifying the LIDAR measurement comprises: Distance measurement information identifying a distance of the target from the electro-optical system.

20. The method of claim 18, wherein the information identifying the LIDAR measurements comprises at least one of: a point cloud determination result associated with the target, The object recognition result of the target, The gesture recognition result of the target, or A three-dimensional sensing determination is performed related to the object.

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