Imaging system having multiple cores

Abstract

The imaging system includes a photonic circuit chip including a plurality of cores, each core including a port through which an output light signal exits the photonic circuit chip. Each core is configured to exit the photonic circuit chip traveling toward a location above or below the photonic circuit chip. Each core is also configured to combine light from one of the output signals with a reference signal to generate a signal that pulsates at a pulsating frequency. The imaging system also includes electronics that use the pulsating frequency from the cores to calculate data indicative of a radial velocity and / or distance between the system and one or more objects located outside the system.

Description

Related Applications

[0001] This application is a continuation of U.S. Patent Application Serial No. 17 / 580,623, entitled "IMAGING SYSTEM HAVING MULTIPLE CORES," filed January 20, 2022, and is hereby incorporated in its entirety.

[0002] The present invention relates to optical devices. In particular, the present invention relates to LIDAR systems.

[0003] As the number of applications supported by optical imaging systems increases, so do the demands on their capabilities. Optical imaging systems typically generate data on a series of sample areas that are sequentially illuminated by a system output signal. The sample area data indicates the radial velocity and / or distance between the imaging system and one or more objects located within the sample area. The imaging system can scan the system output signal to a number of different sample areas. The sample areas can be stitched together to form a field of view for the imaging system. As a result, data from different sample areas provides data for objects within the field of view.

[0004] Increasing the rate at which data can be generated for the field of view can allow the field of view to be scanned more frequently, the size of the field of view to be increased, and / or the resolution of the field of view to be improved. As a result, increasing the data generation rate can increase the number of applications for which an imaging system can be successfully applied. However, increasing the data generation rate often comes at the expense of increasing the complexity and / or cost of the imaging system. As a result, improvements in optical imaging systems are needed. Overview

[0005] The imaging system includes a chip including multiple cores, each core including a port through which an output signal exits the chip. Each core is configured such that the output signal exits the chip and travels toward a location above or below the chip. Each core is further configured to combine light from one of the output signals with a reference signal to generate a signal that pulsates at a pulsating frequency. The imaging system also includes electronics that use the pulsating frequency from the cores to calculate data indicative of a radial velocity and / or distance between the system and one or more objects located outside the system.

[0006] In some examples, each core includes multiple alternative waveguides, any of which can receive the launch signal, and the cores are configured such that the direction in which the launch signal travels away from the tip changes in response to a change in the alternative waveguide that receives the launch signal.

[0007] Another embodiment of a system includes a chip including an optical switch and a plurality of alternative waveguides. The optical switch directs an outgoing signal to any one of the alternative waveguides. The chip includes a port configured to receive an outgoing signal from any one of the alternative waveguides. The port is configured such that the outgoing signal exits through the port and travels toward a position above or below the chip. The direction in which the outgoing signal travels away from the port changes in response to a change in the alternative waveguide receiving a switch signal. [Brief description of the drawings]

[0008] FIG. 1A shows an imaging system that includes a chip having photonic circuits.

[0009] FIG. 1B illustrates another embodiment of an imaging system including a photonic circuit chip.

[0010] FIG. 1C illustrates another embodiment of an imaging system including a photonic circuit chip.

[0011] Figures 2A-2D show an example of a suitable port for use with the photonic circuit chip of Figures 1A-1C. Figure 2A is a schematic diagram of a portion of a photonic circuit chip. The photonic circuit chip includes a plurality of alternative waveguides that exchange optical signals with the port. The port includes a redirection portion.

[0012] FIG. 2B is a cross-sectional view of FIG. 2A taken along the longitudinal axis of one of the alternative waveguides.

[0013] FIG. 2C is a cross-sectional view of the beam steering portion taken along the line labeled C in FIG. 2A.

[0014] 2D is a schematic diagram of a portion of a photonic circuit chip that includes a plurality of alternative waveguides that exchange optical signals with the port, or includes a plurality of input waveguides that exchange optical signals with the port.

[0015] Figure 3 is a cross-sectional view of a silicon-on-insulator wafer.

[0016] Figures 4A-4B show a suitable structure for a redirector on a silicon-on-insulator platform, with Figure 4A being a top view of the redirector.

[0017] FIG. 4B is a cross-sectional view of the redirector of FIG. 4A taken along the line labeled B in FIG. 4A.

[0018] FIG. 4C is a cross-sectional view of another embodiment of a redirect portion.

[0019] FIG. 4D is a cross-sectional view of another embodiment of a redirect portion.

[0020] FIG. 4E is a cross-sectional view of another embodiment of a redirect portion.

[0021] FIG. 4F is a cross-sectional view of another embodiment of a redirect portion.

[0022] Figures 5A-5B show a taper applied to an alternative or input waveguide: Figure 5A is a top view of a portion of the waveguide including the taper.

[0023] FIG. 5B is a cross-sectional view of the portion of the photonic circuit chip shown in FIG. 5A taken along the line labeled B.

[0024] FIG. 5C is a cross-sectional view of the portion of the photonic circuit chip shown in FIG. 5A taken at the line labeled C.

[0025] 6A and 6B show an example of an optical switch including a cascaded Mach-Zehnder interferometer, with Fig. 6A being a top view of the optical switch.

[0026] FIG. 6B is a cross-sectional view of the optical switch shown in FIG. 6A taken along the line labeled B in FIG. 6A.

[0027] FIG. 7 shows the port of FIG. 2B used in combination with optical components including a beam shaper, a sight, and one or more beam steering sections.

[0028] Figures 8A-8C show an example of an adapter suitable for use with an imaging system constructed according to Figure 1B or 1C. Figure 8A shows the path an optical signal takes from a photonic circuit chip through the adapter and out of the adapter.

[0029] FIG. 8B shows the path that an optical signal takes from an object external to the LIDAR system through the adapter to the photonic circuit chip.

[0030] FIG. 8C compares the paths that optical signals carrying different channels take through the adapter of FIG. 8A.

[0031] FIG. 9A is a schematic diagram of the relationship between an imaging system and a field of view.

[0032] FIG. 9B is a side view of an imaginary plane from FIG. 9A.

[0033] FIG. 9C is a side view of another embodiment of the imaginary plane from FIG. 9A.

[0034] FIG. 9D shows a composite field generated from an arrangement of the fields shown in FIG.

[0035] 10A to 10B show an example of a processing section applied to a processing section in an imaging system constructed according to FIGS. 1A to 1C.

[0036] FIG. 10B is a schematic diagram of an example of a photovoltaic assembly applied to the processing portion of FIG. 10A.

[0037] FIG. 10C shows the frequency of the signal output from the imaging system over time.

[0038] FIG. 10D is a schematic diagram of the relationship between the optical sensors included in the LIDAR system and the electronics included in the imaging system.

[0039] FIG. 11A is a top view of a portion of a photonic circuit chip having six different cores, each of which can be constructed according to FIG. 1A.

[0040] FIG. 11B is a top view of a portion of a photonic circuit chip having three different cores that can be constructed according to FIG. 1B or FIG. 1C, respectively.

[0041] FIG. 12 is a schematic diagram of a light source suitable for use with an imaging system having a photonic circuit chip with multiple cores.

[0042] 13A to 13F show the configuration of a photonic circuit chip, including a transfer chip and a pulsation signal generating chip, and Fig. 13A is a top view of the pulsation signal generating chip.

[0043] FIG. 13B is a top view of a portion of a pulsatile signal generating chip including multiple cores.

[0044] FIG. 13C is a top view of the transfer chip.

[0045] FIG. 13D is a perspective view of a portion of the pulsatile signal generating chip shown in FIG. 13A or FIG. 13B.

[0046] FIG. 13E is a perspective view of a portion of the transfer tip.

[0047] Figure 13F shows the interface between a transfer chip constructed according to Figure 13E and a signal-generating chip constructed according to Figure 13D. Figure 13F is a cross-sectional view of the system taken through an alternative waveguide on the pulsatile signal-generating chip and a second alternative waveguide on the transfer chip.

[0048] FIG. 14 shows an imaging system having optical components that exchange optical signals with multiple different cores on a photonic circuit chip.

[0049] FIG. 15 illustrates another embodiment of an imaging system having optical components that exchange optical signals with multiple different cores on a photonic circuit chip.

[0050] The LIDAR system includes a LIDAR chip including multiple LIDAR cores, each LIDAR core including a port through which an outgoing LIDAR signal exits the LIDAR chip. Each LIDAR core is configured to exit the LIDAR chip with an outgoing LIDAR signal traveling toward a location above or below the LIDAR chip. Each core is also configured to combine light from one of the outgoing LIDAR signals with a reference signal to generate a signal that pulsates at a pulsating frequency. The LIDAR system also includes electronics that use the pulsating frequency from the cores to calculate LIDAR data indicative of a radial velocity and / or distance between the LIDAR system and one or more objects located outside the LIDAR system.

[0051] Because the ports direct the outgoing LIDAR signal to a location above or below the LIDAR chip, the ports can be located anywhere on the LIDAR chip, rather than at the edge of the LIDAR chip. Because the ports can be located anywhere on the LIDAR chip, the ports can be arranged in a one-dimensional or two-dimensional array on the LIDAR chip.

[0052] The LIDAR system is configured to output multiple system output signals, each of which can be scanned with a different field of view. Each system output signal includes light from a different one of the outgoing LIDAR signals. As a result, each system output signal and each field of view is associated with a different one of the cores. The different fields of view can be stitched together to form a composite field of view of the LIDAR system. Because the ports are aligned, the optics required to align the fields of view are also simplified. As a result, the ability of the LIDAR system to simultaneously scan multiple fields of view is simplified. This ability to simultaneously scan multiple fields of view can increase the frequency at which a composite field of view can be scanned, increase the size of the composite field of view, and / or improve the resolution of the composite field of view.

[0053] FIG 1A is a schematic diagram of a LIDAR system including a LIDAR chip 2. FIG 1A includes a top view of a portion of the LIDAR chip 2. The LIDAR chip includes a LIDAR core 4. The LIDAR core 4 includes a photonic integrated circuit. The photonic circuit includes a pulsating signal generator 6 and a transfer unit 8. The pulsating signal generator 6 includes components for generating a pulsating optical signal from which LIDAR data is generated. The transfer unit 8 includes one or more components for managing the input and / or output of optical signals to and / or from the LIDAR chip.

[0054] The LIDAR core can include a light source 10 that outputs an outgoing LIDAR signal. The LIDAR core can include a utility waveguide 12 that receives the outgoing LIDAR signal from the light source 10. The utility waveguide 12 transmits the outgoing LIDAR signal to a signal guiding section 14. The signal guiding section 14 can be operated by electronics to steer light from the light source output signal to one of a number of different alternative waveguides 16. There are N alternative waveguides, with each alternative waveguide 16 associated with an alternative waveguide index i, where i has a value between 1 and N. Suitable values ​​for N include, but are not limited to, values ​​less than 128, 64, or 32, and / or greater than 2, 8, or 16. In one example, N is between 2 and 128.

[0055] Each alternative waveguide 16 can receive an outgoing LIDAR signal from the signal directing portion 14. When any of the alternative waveguides 16 receives an outgoing LIDAR signal, that alternative waveguide 16 transmits the outgoing LIDAR signal to a port 18 through which the outgoing LIDAR signal can exit the LIDAR chip and serve as a LIDAR output signal.

[0056] 1A has multiple arrows each representing a LIDAR output signal traveling in a different direction away from the LIDAR chip. The ports 18 are constructed such that the direction in which the LIDAR output signal travels away from the LIDAR chip is a function of the alternative waveguide 16 in which the outgoing LIDAR signal is guided. The optical signal resulting from the outgoing LIDAR signal being guided in an alternative waveguide 16 of alternative waveguide index i is represented by a channel (C i ) are classified as optical signals carrying a different waveguide index. Thus, each LIDAR output signal is associated with a different one of the alternative waveguide indices (i=1 to N). For example, the path of a LIDAR output signal carrying a channel with an alternative waveguide index of 2 is shown in FIG. 1A as C 2 For the sake of explanation, this LIDAR system is 1 ~C 3Each of the different LIDAR output signals may carry a different channel, but each of the different channels may carry the same wavelength selection or substantially the same wavelength selection.

[0057] The LIDAR system includes one or more optical components 20 that receive a LIDAR output signal output from a LIDAR chip. The one or more optical components 20 output a system output signal that includes, consists of, or consists essentially of light from the LIDAR output signal. If the LIDAR system does not include one or more optical components, the LIDAR output signal can function as a system output signal. Examples of optical components that can be included in the one or more optical components 20 include, but are not limited to, components selected from the group consisting of beam shaping elements such as lenses, beam directors such as mirrors, beam steering devices such as steerable mirrors, and combinations thereof.

[0058] The system output signal travels away from the LIDAR system and may be reflected by an object 22 in the path of the system output signal. The reflected signal travels away from the object. When a LIDAR output signal is reflected, at least a portion of the light from the reflected light may return to the LIDAR system as a system return signal. The system return signal may travel from the object to the one or more optical components along the same or substantially the same path traveled by the system output signal. Thus, the one or more optical components 20 receive the system return signal.

[0059] The one or more optical components 20 may output a LIDAR input signal that includes, consists of, or consists essentially of light from the system return signal. The LIDAR input signal may travel from the one or more optical components 20 to port 18 along the same or substantially the same path as traveled by the LIDAR output signal. Thus, port 18 receives the LIDAR input signal.

[0060] The LIDAR input signal may enter utility waveguide 12 through port 18. The portion of the LIDAR input signal that enters port 18 may function as the incident LIDAR signal. The port directs the incident LIDAR signal to one of the alternative waveguides. For example, port 18 may be used to direct channel C. i An incident LIDAR signal carrying a different channel is directed to an alternate waveguide 16 associated with alternate waveguide index i. As a result, incident LIDAR signals carrying different channels are directed to different alternate waveguides. The alternate waveguide receiving the incident LIDAR signal transmits the incident LIDAR signal to a signal directing portion 14. The signal directing portion 14 outputs the incident LIDAR signal onto the utility waveguide 12.

[0061] The utility waveguide 12 transmits the incident LIDAR signal to a splitter 24, which moves a portion of the incident LIDAR signal from the utility waveguide 12 onto a comparison waveguide 26 as a comparison signal. The comparison waveguide 26 transmits the comparison signal to a processing unit 28 for further processing. Suitable splitters 24 include, but are not limited to, optical couplers, Y-junctions, and MMIs.

[0062] The utility waveguide 12 also transmits the outgoing LIDAR signal to a splitter 24, which moves a portion of the outgoing LIDAR signal as a reference signal from the utility waveguide 12 onto a reference waveguide 32. The reference waveguide 32 transmits the reference signal to the processing unit 28 for further processing.

[0063] As will be described in more detail below, the processing unit 28 combines the comparison signal with the reference signal to form a composite signal conveying LIDAR data for a sample area on the field of view, which can then be processed to extract LIDAR data for the sample area (radial velocity and / or distance between the LIDAR system and objects external to the LIDAR system).

[0064] The LIDAR chip may include a control branch for controlling the operation of the light source 10. The control branch includes a directional coupler 66 that moves a portion of the outgoing LIDAR signal from the utility waveguide 12 onto a control waveguide 68. The combined portion of the outgoing LIDAR signal serves as a tapped signal. Although FIG. 1A shows a directional coupler 66 that moves a portion of the outgoing LIDAR signal onto the control waveguide 68, other signal taps may be used to move a portion of the outgoing LIDAR signal from the utility waveguide 12 onto the control waveguide 68. Examples of suitable signal taps include, but are not limited to, a Y-junction and an MMI.

[0065] The control waveguide 68 transmits the tapped signal to a controller 70, which may be in electrical communication with the electronics 62. In operation, the electronics 62 may adjust the frequency of the outgoing LIDAR signal in response to the output from the controller. One example of a suitable configuration for a controller is described in U.S. Patent Application Serial No. 15 / 977,957, filed May 11, 2018, and entitled "Optical Sensor Chip," which is incorporated herein in its entirety.

[0066] In the LIDAR chip of FIG. 1A, the LIDAR input signal is received at the same port 18 that outputs the LIDAR output signal. However, the LIDAR chip of FIG. 1A may be modified such that the LIDAR input signal is received at a different port than the port that outputs the LIDAR output signal. As an example, FIG. 1B shows a LIDAR system having a LIDAR chip in which the LIDAR input signal is received at a different port than the port that outputs the LIDAR output signal. The LIDAR chip includes an input port 72 that receives the LIDAR input signal from one or more optical components 20. Each of the LIDAR input signals is assigned to a channel (C) depending on which alternative waveguide 16 receives the light transmitted in the LIDAR input signal. iThe input ports 72 direct each of the LIDAR input signals to one of several input waveguides 74. The input ports direct LIDAR input signals carrying different channels to different input waveguides 74. For example, channel C 1 The LIDAR input signal is transmitted to the FLIS C1 , which is directed to one of the input waveguides 74 and is also directed to one of the channels C 3 The LIDAR input signal is transmitted to the FLIS C3 and are guided into a different input waveguide 74.

[0067] Each LIDAR input signal is incident on one of the input waveguides 74 and serves as a first comparison signal. Each input waveguide 74 transmits the comparison signal received by that input waveguide 74 to a second signal guide 76, which may be a signal combiner that directs the comparison signals transmitted on the different input waveguides 74 to a comparison waveguide 26. The comparison waveguide 26 transmits the received comparison signal to a processing unit 28 for further processing. Suitable second signal guides 76 include, but are not limited to, wavelength-independent signal combiners, such as optical couplers, Y-junctions, MMIs, cascaded evanescent optical couplers, and cascaded Y-junctions.

[0068] The LIDAR chip in the LIDAR system of FIG. 1B may be modified so that the comparison signals transmitting different channels are received at different processing units 28. FIG. 1C shows a LIDAR system with a LIDAR chip in which the comparison signals transmitting different channels are received at different processing units 28. Each of the input waveguides 74 transmits one of the comparison signals to a different one of the processing units 28. Also, the splitter 24 moves a portion of the outgoing LIDAR signal onto the intermediate waveguide 78 as a preliminary reference signal. The intermediate waveguide 44 transmits the preliminary reference signal to a reference splitter 80. The reference splitter 80 is configured to split the preliminary reference signal into reference signals that are each received at a different one of the multiple reference waveguides 32. The reference splitter 80 can be a wavelength-independent splitter, such as an optical coupler, a Y-junction, an MMI, a cascaded evanescent optical coupler, or a cascaded Y-junction. As a result, each of the reference signals can have the same or approximately the same wavelength distribution. For example, the reference splitter 80 can be configured such that each first reference signal carries the same or substantially the same selection of wavelengths. Each reference waveguide 32 directs one of the reference signals to one of the processing units 28. The reference waveguide 32 and input waveguide 74 are arranged such that each processing unit 28 receives a reference signal and a comparison signal.

[0069] 2A-2D show an example of a suitable port 18 for use with the LIDAR chip of FIGS. 1A-1C. As described below, the port structure of FIGS. 2A-2C is also suitable for use as the input port 72 of FIGS. 1B and 1C. FIG. 2A is a schematic diagram of a top view of the port 18. The port 18 includes a redirector 82 that receives the outgoing LIDAR signal from any one of the alternative waveguides 16. The redirector 82 redirects the received outgoing LIDAR signal such that the direction in which the outgoing LIDAR signal travels away from the redirector 82 changes in response to changes in the alternative waveguide 16 from which the redirector 82 receives the outgoing LIDAR signal. The portion of the outgoing LIDAR signal that travels away from the redirector 82 serves as an output signal.

[0070] FIG 2B shows an example structure of a port configured according to FIG 2A. FIG 2B is a cross-sectional view of FIG 2A taken along the longitudinal axis of one of the alternative waveguides 16. The portion of the LIDAR chip shown in FIG 2B shows the alternative waveguide 16 disposed on a base 81. The illustrated alternative waveguide 16 terminates in a redirection portion 82 that includes a reflective surface 84. The outgoing LIDAR signal exits the alternative waveguide 16 and is received at the reflective surface 84. The reflected portion of the outgoing LIDAR signal serves as an output signal.

[0071] The redirector 82 may be configured such that the direction in which the output signal travels away from the redirector 82 causes the output signal to travel to a beam directing component 86 that receives the output signal and outputs at least a portion of the light from the output signal as a LIDAR output signal. The beam directing component 86 is configured such that the direction in which the LIDAR output signal travels away from the beam directing component 86 is different than the direction of the output signal.

[0072] Suitable beam guides 84 include, but are not limited to, lenses, mirrors, and diffractive optical elements. The beam guide 86 shown in FIG. 2B is a lens. In some examples, when the beam guide 86 is a lens, the lens may be configured to collimate the LIDAR output signal. When the beam guide 86 is a lens, suitable materials for the beam guide 86 include, but are not limited to, glass, plastic, and silicon. The beam guide 86 may be secured onto the LIDAR chip using mechanisms including, but not limited to, epoxy bonding and mechanical clamps.

[0073] The beam directing portion 86 is configured such that the direction in which the LIDAR output signal travels away from the beam directing portion 86 is a function of the alternative waveguide 16 that receives the outgoing LIDAR signal. For example, the direction in which the LIDAR output signal travels away from the beam directing portion 86 changes in response to changes in the alternative waveguide 16 that receives the outgoing LIDAR signal that carries the light contained in the LIDAR output signal.

[0074] To illustrate that the direction in which the LIDAR output signal travels away from the beam guide 86 is a function of the alternate waveguide 16, in FIG. 2A, the location at which the LIDAR output signal exits the beam guide 86 is C i=1 ~C i=N These notations indicate which of the alternative waveguides 16 received the LIDAR output signal to cause the LIDAR output signal to exit the beam steering section 86 at the location shown. As an example, when an alternative waveguide 16 with alternative waveguide index i=N receives the exit LIDAR signal, the LIDAR output signal is expressed as C i=N The beam emerges from the beam guide portion 86 at the position indicated by .

[0075] FIG. 2C is a cross-sectional view of the beam directing portion 86 taken along the line labeled C in FIG. 2A. i=1 ~C i=N As is apparent from FIG. 2C, the path of the output signal through the beam guiding portion 86 changes with the change in the alternate waveguide 16 that receives the outgoing LIDAR signal. As a result of the different paths that the output signal may travel through the beam guiding portion 86, the LIDAR output signals travel away from the beam guiding portion 86. In some examples, the directions that the different LIDAR output signals travel away from the beam guiding portion 86 may be non-parallel, as shown in FIG. 2C.

[0076] Since the direction in which the LIDAR output signal travels away from the beam directing portion 86 varies depending on the alternative waveguide 16 that receives the outgoing LIDAR signal, the electronics can steer the direction of the LIDAR output signal by operating the signal directing portion 14 to change the alternative waveguide 16 that receives the outgoing LIDAR signal. If the LIDAR output signal serves as a system output signal, the electronics can steer the direction of the system output signal by operating the signal directing portion 14 to change the alternative waveguide 16 that receives the outgoing LIDAR signal. As will become apparent below, the one or more optical components 20 can be configured such that changing the direction in which the LIDAR output signal travels away from the beam directing portion 86 changes the direction in which the system output signal travels away from the LIDAR system. As a result, if the LIDAR system includes one or more optical components 20, the electronics can steer the direction of the system output signal by operating the signal directing portion 14 to change the alternative waveguide 16 that receives the outgoing LIDAR signal. Thus, the electronics can operate the signal directing portion 14 as a signal steering mechanism.

[0077] 2A-2C show a redirector 82 that receives the LIDAR output signal from a different alternative waveguide 16. A port can include multiple redirectors 82, each of which receives the LIDAR output signal from a different alternative waveguide 16. As an example, FIG. 2D shows the port 18 of FIG. 2A modified to have multiple redirectors 82, each of which receives the LIDAR output signal from a different one of the alternative waveguides 16.

[0078] Port 18 shown in Figures 2A-2D may be operated in reverse as disclosed in the context of Figure 1A. For example, beam steering 86 receives a LIDAR input signal and outputs an input signal that includes, consists of, or consists essentially of light from the LIDAR input signal. The input signal is received by redirection 82. Redirection 82 outputs the incident LIDAR signal to one of alternative waveguides 26. The incident LIDAR signal includes, consists of, or consists essentially of light from the input signal. Alternate waveguide 16 transmits the incident LIDAR signal to the signal steering as disclosed in the context of Figure 1A. The signal steering 14 functions as a signal combiner that directs the incident LIDAR signal to utility waveguide 12. Light from the LIDAR input signal carrying channel i travels through port 18 in the reverse direction, substantially the same path as the output signal carrying channel i. As a result, the ports 18 direct input signals carrying different channels to different alternative waveguides 16 .

[0079] The port 18 shown in Figures 2A-2D can function as the input port 72 disclosed in the context of Figures 1B and 1C. For example, the beam steering unit 86 receives a LIDAR input signal and outputs an input signal that includes, consists of, or consists essentially of light from the LIDAR input signal. The input signal is received by the redirection unit 82. The redirection unit 82 outputs the incident LIDAR signal to one of the input waveguides 74. The incident LIDAR signal includes, consists of, or consists essentially of light from the input signal. Light from the LIDAR input signal carrying channel i travels through the port 18 in the reverse direction, substantially the same path as the output signal carrying channel i. As a result, the port 18 directs input signals carrying different channels to different input waveguides 74.

[0080] Suitable platforms for the LIDAR chip include, but are not limited to, silica, indium phosphide, and silicon-on-insulator wafers. FIG. 3 is a cross-sectional view of a silicon-on-insulator wafer. A silicon-on-insulator (SOI) wafer includes a buried layer 90 between a substrate 92 and an optical transmission medium 94. In a silicon-on-insulator wafer, the buried layer 90 is silica, and the substrate and the optical transmission medium 94 are silicon. A substrate of an optical platform, such as a SOI wafer, can serve as a base for a LIDAR chip. For example, in some examples, the optical components shown in FIGS. 1A-1C can be disposed on the top and / or side surfaces of the same substrate. As a result, a substrate of an optical platform, such as a SOI wafer, can serve as a base 81 shown in FIG. 2B.

[0081] The portion of the LIDAR chip shown in Figure 3 includes a waveguide structure suitable for use with a chip constructed from a silicon-on-insulator wafer. A ridge 96 of an optical transmission medium 94 extends away from a slab region 98 of the optical transmission medium 94. An optical signal is constrained between the top of the ridge and the buried layer 90. As a result, the ridge 96 at least partially defines the waveguide.

[0082] The dimensions of the ridge waveguide are labeled in FIG. 3. For example, the ridge has a width labeled w and a height labeled h. The thickness of the slab region is labeled t. In LIDAR applications, these dimensions may be more important than in other applications due to the need to use higher levels of optical power than in other applications. The ridge width (labeled w) is greater than 1 μm and less than 4 μm, the ridge height (labeled h) is greater than 1 μm and less than 4 μm, and the thickness of the slab region is greater than 0.5 μm and less than 3 μm. These dimensions may apply to straight or substantially straight portions of the waveguide, curved portions of the waveguide, and tapered portions of the waveguide. These portions of the waveguide are therefore single mode. However, in some examples, these dimensions apply to straight or substantially straight portions of the waveguide. Additionally or alternatively, the curved portions of the waveguide may have a reduced slab thickness to reduce optical loss in the curved portions of the waveguide. For example, the curved portion of the waveguide may have a ridge extending away from the slab region having a thickness of 0.0 μm or more and less than 0.5 μm. The above dimensions generally provide straight or substantially straight portions of the waveguide with a single mode structure, but they may result in tapered and / or curved portions that are multimode. Coupling between multimode and single mode geometries can be achieved using tapers that do not substantially excite higher order modes. Thus, the waveguide may be configured such that signals transmitted within the waveguide are transmitted in a single mode even when transmitted in a waveguide section having multimode dimensions. The waveguide structure of FIG. 3 is suitable for all or part of the waveguide on a LIDAR chip constructed according to FIGS. 1A-2D.

[0083] 4A-4B show a suitable structure for the redirector 82 on a silicon-on-insulator platform. FIG. 4A is a top view of the redirector 82, and FIG. 4B is a cross-sectional view of the redirector 82 of FIG. 4A taken along the line labeled B. The redirector 82 includes a port recess 100 that extends into the first optical transmission medium 94. The port recess 100 includes one or more side surfaces. The illustrated embodiment includes a bottom surface 102 and multiple side surfaces including a waveguide side surface 104 and a reflective surface 106 that functions as the reflective surface 84.

[0084] A second optical transmission medium 108 is disposed within the port recess 100. The second optical transmission medium 108 may be a liquid or gas, and is preferably a solid. The second optical transmission medium 108 may have a different refractive index than the optical transmission medium 108. Suitable second optical transmission mediums 108 include, but are not limited to, air, epoxies, polymers, spin-on glass, and evaporated or smoulded films. An example of a suitable polymer is polyimide PI2611, which is not a substantial stress source for optical devices built on silicon-on-insulator wafers.

[0085] As seen in FIG. 4B, the waveguide side 104 can be disposed at an angle γ measured relative to the base 81, and the reflective surface 106 can be disposed at an angle α measured relative to the base 81. The angle γ can be the same as or different from the angle α. Suitable angle ranges for γ and / or α include ranges from 0° to 90° and 45° to 90°, and are less than 89°, 87°, or 85°. When the optical transmission medium 94 is silicon and the port recess 100 is formed by etching, a suitable angle for γ and / or α is about 54.7° because the crystal structure of the silicon layer naturally etches the side of the port recess 100 at an angle of about 54.7°. In one example, the angle γ is about 90° and the angle α is about 54.7°.

[0086] During operation of the LIDAR chip, the outgoing LIDAR signal guided by the alternative waveguide 16 travels to the end of the alternative waveguide 16 and travels in a propagation direction just before exiting the alternative waveguide 16. The outgoing LIDAR signal exits the alternative waveguide 16 and is received by the second optical transmission medium 108. The outgoing LIDAR signal travels through the second optical transmission medium 108 traveling in a first direction. The first direction may be the same as or different from the propagation direction. For example, if the propagation direction is not perpendicular to the waveguide side 104 and the second optical transmission medium 108 has a different refractive index than the first optical transmission medium, there may be some refraction that changes the direction of the outgoing LIDAR signal as it enters the second optical transmission medium. The outgoing LIDAR signal travels through the second optical transmission medium 108 to a reflecting surface 106, which reflects the outgoing LIDAR signal. The outgoing LIDAR signal then passes through the second optical transmission medium 108 and exits the second optical transmission medium 108. Before exiting the second optical transmission medium 108, the outgoing LIDAR signal travels in a second direction. The second direction is toward a location on a non-side of the LIDAR chip, such as the top surface of the device or the bottom side of the LIDAR chip. For example, the second direction may be toward the beam guide 86, as shown in FIG. 2B. FIG. 4B illustrates the second direction toward a location on the top of the LIDAR chip. The portion of the outgoing LIDAR signal that exits the second optical transmission medium 108 can serve as an output signal.

[0087] In some examples, the outgoing LIDAR signal and / or the incoming LIDAR signal travels through a partial free space region 99 between all or a portion of the alternative waveguide 16 and the redirection portion 82. The partial free space region 100 may be free space horizontally, but is guided vertically. A portion of the free space region 99 may terminate at a waveguide side 104, as seen in FIG. 4A. Thus, the waveguide side 104 may function as a facet of the alternative waveguide.

[0088] 4A and 4B can operate in reverse when the redirector receives an input signal. For example, redirector 82 can operate in reverse as disclosed in the context of FIG 1A and / or be included in input port 72 as disclosed in the context of FIG 1A and 1B.

[0089] The port recess 100 can have other configurations. For example, the port recess 100 can be constructed such that reflection occurs at the waveguide side 104, as shown in Figures 4C and 4D. As a result, the waveguide side 104 can function as a reflective surface. The reflection can result from the presence of a reflective material 110. For example, Figure 4E shows the redirection portion 82 of Figure 4A constructed with a reflective material 110 on the reflective surface 106 of the port recess 100. Although the reflective material 110 is shown on the reflective surface 106, the reflective material 110 can be disposed on the waveguide side 104. Suitable reflective media include, but are not limited to, reflective metals such as Al and Au. Alternatively, the reflection can be the result of total internal reflection (TIR). For example, the reflection can be the result of a change in the refractive index at the reflective surface and / or a change in the angle between the optical signal and the reflective surface. Thus, the second optical transmission medium 108 can be selected to provide a specific change in the refractive index at the reflective surface.

[0090] Although the port recesses disclosed in Figures 1A-4E are constructed to direct the outgoing LIDAR signal to exit the LIDAR chip traveling in a direction above the LIDAR chip, the port recesses can be constructed to direct the outgoing LIDAR signal to a location below the LIDAR chip. For example, Figure 4F shows a port recess configured to direct the outgoing LIDAR signal toward a location below the LIDAR chip. The configuration of Figure 4F can be achieved by selection of the second optical transmission medium 108 and / or the angle between the optical signal and the reflective surface.

[0091] In some examples, all or a portion of the alternative waveguide 16 and / or all or a portion of the input waveguide 74 include a taper 112 as shown in FIGS. 5A-5C. FIG. 5A is a top view of a portion of the LIDAR chip. FIG. 5B is a cross-sectional view taken along the line labeled B of the portion of the LIDAR chip shown in FIG. 5A. FIG. 5C is a cross-sectional view taken along the line labeled C of the portion of the LIDAR chip shown in FIG. 5A. The illustrated alternative waveguide 16 includes a horizontal taper as evident in FIG. 5A and a vertical taper as evident in FIG. 5B. However, the alternative waveguide 16 may include only a horizontal taper or only a vertical taper. The spread of the outgoing LIDAR signal, and therefore the system output signal, may decrease as the cross-sectional dimension of the alternative waveguide 16 increases. As a result, the taper 112 may reduce the spread of the outgoing LIDAR signal and / or the output signal.

[0092] The second optical transmission medium 108 may optionally be disposed within the port recess 28 and may optionally be disposed above the taper 112 as is evident from Figures 5A and 5B. For purposes of illustration, in Figure 5A the second optical transmission medium 108 is shown as transparent to allow viewing of the horizontal taper below. As evident from Figure 5B, disposing the second optical transmission medium 108 above the taper 112 provides a continuous flat surface above the taper 112.

[0093] The taper 112 can be an adiabatic taper. In some examples, the taper increases from single mode dimensions to multimode dimensions. The taper dimensions are labeled in FIG. 5C. For example, the ridge has a width labeled w and a height labeled h. In some examples, the taper is constructed to provide the alternative waveguide 16 with one or more conditions selected from the group consisting of: a width (w) increasing from greater than 1 μm and less than 4 μm to a width (W) increasing from greater than 5 μm and less than 15 μm, and a height (h) increasing from greater than 1 μm and less than 4 μm to a height (H) increasing from greater than 5 μm and less than 15 μm.

[0094] Suitable signal guiding units 14 for use with the LIDAR chip include optical switches such as, but not limited to, cascaded Mach-Zehnder interferometers and micro-ring resonator switches. In one example, the signal guiding unit 14 includes a cascaded Mach-Zehnder interferometer using a thermal phase shifter or a free carrier injection phase shifter. Figures 6A and 6B show an example of an optical switch including a cascaded Mach-Zehnder interferometer 116. Figure 6A is a top view of the optical switch. Figure 6B is a cross-sectional view of the optical switch shown in Figure 6A taken along the line labeled B in Figure 6A.

[0095] The optical switch receives an outgoing LIDAR signal from a utility waveguide 12. The optical switch is configured to direct the outgoing LIDAR signal to one of several alternative waveguides 16. The optical switch includes an interconnecting waveguide 114 connecting a plurality of Mach-Zehnder interferometers 116 in a cascaded arrangement. Each Mach-Zehnder interferometer 116 directs an outgoing LIDAR signal to one of two interconnecting waveguides 114. Electronics can operate each Mach-Zehnder to select which of the two interconnecting waveguides 114 receives the outgoing LIDAR signal from the Mach-Zehnder interferometer 116. The interconnecting waveguide 114 that receives the outgoing LIDAR signal can be selected such that the outgoing LIDAR signal is directed through the optical switch to a particular one of the alternative waveguides 16.

[0096] Each Mach-Zehnder interferometer 116 includes two branch waveguides 118, each of which receives a portion of the outgoing LIDAR signal from the utility waveguide 12 or from the interconnecting waveguide 114. Each Mach-Zehnder interferometer 116 includes a guide section 120 that receives the two portions of the outgoing LIDAR signal from the branch waveguide 118. The guide section 120 steers the outgoing LIDAR signal to one of the two interconnecting waveguides 114 that are configured to receive the outgoing LIDAR signal from the guide section 120. The interconnecting waveguide 114 to which the outgoing LIDAR signal is guided is a function of the phase difference between the two different portions of the outgoing LIDAR signal received by the guide section 120. Although FIG. 6A shows a directional coupler acting as the guide section 120, other guide sections 120 can be used. Suitable alternatives for the guide section 120 include, but are not limited to, a multimode interference (MMI) device and a tapered coupler.

[0097] Each Mach-Zehnder interferometer 116 includes a phase shifter 122 disposed along one of the branch waveguides 118. The output section includes conductors 124 in electrical communication with the phase shifter 122. The conductors 124 are shown in dashed lines so that they can be easily distinguished from the components below. The conductors 124 each terminate at a contact pad 126. The contact pads 126 can be used to provide electrical communication between the conductors 124 and electronics. Thus, the conductors 124 provide electrical communication between the electronics and the phase shifter 122, allowing the electronics to operate the phase shifter 122. Suitable conductors 124 include, but are not limited to, metal traces. Suitable materials for the conductors include, but are not limited to, titanium, aluminum, and gold.

[0098] The electronics can operate each phase shifter 122 to control the phase difference between portions of the outgoing LIDAR signal received by the guiding portion 120. In one example, the phase shifter 122 can be operated to vary the refractive index of at least a portion of the branch waveguide 118. Changing the refractive index of a portion of the branch waveguide 118 in the Mach-Zehnder interferometer 116 changes the effective length of that branch waveguide 118, and therefore the phase difference between portions of the outgoing LIDAR signal received by the guiding portion 120. The ability of the electronics to vary the phase difference allows the electronics to select which interconnecting waveguide 114 receives the outgoing LIDAR signal from the guiding portion 120.

[0099] FIG. 6B illustrates an example of a suitable configuration of a phase shifter 122 on a branch waveguide 118. The branch waveguide 118 is at least partially defined by a ridge 96 of the optical transmission medium 94 extending away from a slab region 98 of the optical transmission medium 94. The doped regions 128 extend into the slab region 98, one of the doped regions including an n-type dopant and one of the doped regions 128 including a p-type dopant. The first cladding 130 is disposed between the optical transmission medium 94 and the conductor 1244. The conductors 124 each extend through an opening in the first cladding 130 to contact one of the doped regions 128. The second cladding 132 is optionally disposed over the first cladding 130 and over the conductor 124. To generate a current through the branch waveguide 118, the electronics can apply a forward bias to the conductor 124. As a result, injecting carriers into the branch waveguide 118 causes absorption of free carriers within the branch waveguide 118 which changes the refractive index.

[0100] The first cladding 130 and / or second cladding 132 shown in FIG. 6B may each represent one or more layers of material. The materials of the first cladding 130 and / or second cladding 132 may be selected to provide electrical insulation for the conductor 124, a lower refractive index relative to the optical transmission medium 94, stress reduction, and mechanical and environmental protection. Suitable materials for the first cladding 130 and / or second cladding 132 include, but are not limited to, silicon nitride, tetraorthosilicate (TEOS), silicon dioxide, silicon nitride, and aluminum oxide. One or more of the materials of the first cladding 130 and / or second cladding 132 may be doped or undoped.

[0101] The one or more optical components 20 may include one or more beam shapers and / or one or more beam steering devices. As an example, FIG. 7 illustrates the port of FIG. 2B used in combination with an optical component 20 including a beam shaper 134 arranged to receive the LIDAR output signal. In some examples, the beam shaper 134 is configured to expand the width of the LIDAR output signal. For example, the beam shaper 134 may output a shaped LIDAR output signal that is wider than the LIDAR output signal received by the beam shaper 134 and / or that increases in width as the shaped LIDAR output signal travels away from the beam shaper 134. Suitable beam shapers 134 include, but are not limited to, concave lenses, convex lenses, plano-concave lenses, and plano-convex lenses.

[0102] The optics 20 includes a sight 136 that receives the outgoing shaped LIDAR output signal and outputs a collimated LIDAR output signal. Suitable sights 136 include, but are not limited to, a convex lens and a GRIN lens.

[0103] The optical component 20 includes one or more beam steering components 138 that receive the collimated LIDAR output signal from the boresight 136 and output a system output signal. In FIG. 7, the direction in which the system output signal travels away from the LIDAR system is d 2The electronics can operate one or more beam steering units 138 to steer the system output signal to different sample areas within the field of view. As a result, the one or more beam steering units 138 can function as beam steering mechanisms operated by the electronics to steer the system output signal within the field of view of the LIDAR system.

[0104] Suitable beam steering components 138 include, but are not limited to, a movable mirror, a MEMS mirror, an optical phased array (OPA), an optical grating, and a driven optical grating.

[0105] FIG. 7 shows optical components 20 including a beam steering section 138, a sight 136, and a beam shaper, however, the beam steering section 138 may include or consist of one, two, or three components selected from the group consisting of a beam steering section, a sight, and a beam shaper.

[0106] In some examples, the optical components 20 include no other optical components, or in addition to one or more other optical components, an adapter that can include, consist of, or function as a circulator configured to separate the LIDAR output signal from the LIDAR input signal, thereby allowing the LIDAR input signal to be received on the input waveguide 74 and the LIDAR output signal to be output from the alternative waveguide 16.

[0107] 8A-8C show an example of an adapter 139 suitable for use with a LIDAR system constructed according to FIG. 1B and / or FIG. 1C (in which port 18 and input port 72 are constructed according to FIG. 2A-2C). For purposes of explanation, an optical signal resulting from an outgoing LIDAR signal being directed into an alternative waveguide 16 of alternative waveguide index i is classified as an optical signal carrying channel i. 2 ) are shown in Figures 8A and 8B.

[0108] The adapter 139 includes multiple adapter parts disposed on a base 140. The adapter parts include a circulator 142. Figures 8A and 8B show one example of a circulator 142 suitable for use with the core of Figures 1B and / or 1C. The path shown in Figure 8A is the channel C traveling from the LIDAR chip through the circulator 142. 2 8B follows the light from the LIDAR output signal traveling through channel C until it leaves the LIDAR system as the system output signal. In contrast, the path shown in FIG. 2 This is the light from the system feedback signal that carries channel C. 2 The LIDAR input signal is transmitted to the LIDAR chip and then tracked until it is incident on the LIDAR chip.

[0109] The circulator 142 is a channel C 2 The first polarizing beam splitter 146 is configured to split the LIDAR output signal into an optical signal having a first polarization state and an optical signal having a second polarization state. The first and second polarization states may be linear polarization states, and the second polarization state is different from the first polarization state. For example, the first polarization state may be TE and the second polarization state may be TM. Alternatively, the first polarization state may be TM and the second polarization state may be TE.

[0110] Since the light source 10 often includes a laser as the source of the light source output signal, the LIDAR output signal may be linearly polarized. Since the light source output signal is the source of the circulator input signal, the LIDAR output signal received by the first polarizing beam splitter 146 may also be linearly polarized. In Figures 8A and 8B, the optical signal in the first polarization state is represented by a vertical double arrow, and the optical signal in the polarization state is represented by a black circle. For the purposes of the following discussion, the LIDAR output signal is assumed to be in the first polarization state, but a LIDAR output signal in a second polarization state is also possible. Since the LIDAR output signal is assumed to be in the first polarization state, the LIDAR output signal is represented by a vertical arrow.

[0111] The LIDAR output signal is assumed to be in a first polarization state, so the first polarizing beam splitter 146 is shown outputting a first polarization state signal in the first polarization state, however, the first polarizing beam splitter 146 is not shown outputting a second polarization state optical signal, because there is no substantial amount of the second polarization state in the LIDAR output signal.

[0112] The circulator 142 may include a second polarizing beam splitter 148 that receives the first polarization state signal. The second polarizing beam splitter 148 splits the first polarization state signal into a first polarized signal and a second polarized signal, where the first polarized signal has the first polarization state but does not have or substantially does not have the second polarization state. And the second polarized signal has the second polarization state but does not have or substantially does not have the first polarization state. Because the first polarization state signal received by the second polarizing beam splitter 148 has the first polarization state but does not have or substantially does not have the second polarization state, the second polarizing beam splitter 148 outputs the first polarized signal but does not substantially output the second polarized signal. The first polarizing beam splitter 146 and the second polarizing beam splitter 148 may have a combined effect of filtering one of the polarization states from the circulator input signal.

[0113] The circulator 142 may include a non-reciprocal polarization rotator 150 that receives the first polarized signal and outputs a first rotated signal. In some examples, the non-reciprocal polarization rotator 150 is configured to rotate the polarization state of the first polarized signal by n*90°+45°, where n is 0 or an even integer. As a result, the polarization state of the first rotated signal is rotated 45° from the polarization state of the first polarized signal. Suitable non-reciprocal polarization rotators 150 include, but are not limited to, non-reciprocal polarization rotators such as a Faraday rotator.

[0114] The circulator 142 may include a 45° polarization rotator 152 that receives the first rotated signal and outputs a second rotated signal. In some examples, the 45° polarization rotator 152 is configured to rotate the polarization state of the first rotated signal by m*90°+45°, where m is 0 or an even integer. As a result, the polarization state of the second rotated signal is rotated 45° from the polarization state of the first rotated signal. The combined effect of the polarization state rotation by the non-reciprocal polarization rotator 150 and the 45° polarization rotator 152 is that the polarization state of the second rotated signal is rotated 90° relative to the polarization state of the first polarized signal. Thus, in the illustrated example, the second rotated signal has a second polarization state. Suitable 45° polarization rotators 152 include, but are not limited to, reciprocal polarization rotators, such as half-wave plates.

[0115] The circulator 142 can include a third polarizing beam splitter 154 that receives the second rotated signal from the 45° polarization rotator 152. The third polarizing beam splitter 154 is configured to split the second rotated signal into an optical signal of a first polarization state and an optical signal of a second polarization state. Because the second rotated signal is of the second polarization state, the third polarizing beam splitter 154 outputs the second rotated signal but substantially no signal of the first polarization state.

[0116] As is evident from FIG. 8A , the first polarizing beam splitter 146, the second polarizing beam splitter 148, the non-reciprocal polarization rotator 150, and the 45° polarization rotator 152 may be included in a parts assembly 156. The parts assembly 156 may be constructed as an integral block. The parts of the parts assembly 156 may be bonded together within the block. In some examples, the parts assembly 156 has a cube, a rectangular prism, a square prism, or a rectangular prism shape.

[0117] The circulator 142 may include a second component assembly 158. In some examples, the second component assembly 158 has the same configuration as the component assembly 156. As a result, the component assembly 156 may also function as the second component assembly 158. The second component assembly 158 may receive the second rotated signal from the third polarizing beam splitter 148. In particular, a 45° polarization rotator 152 in the second component assembly 158 may receive the second rotated signal from the third polarizing beam splitter 148 and output a third rotated signal. In some examples, the 45° polarization rotator 152 may be configured to rotate the polarization state of the second rotated signal by m*90°+45°, where m is 0 or an even integer. As a result, the polarization state of the third rotated signal is rotated 45° from the polarization state of the second rotated signal. Suitable 45° polarization rotators 152 include, but are not limited to, reciprocal polarization rotators, such as half-wave plates.

[0118] The second component assembly 158 can include a non-reciprocal polarization rotator 150 that receives the third rotated signal and outputs a fourth rotated signal. In some examples, the non-reciprocal polarization rotator 150 is configured to rotate the polarization state of the third polarized signal by n*90°+45°, where n is 0 or an even integer. As a result, the polarization state of the fourth rotated signal is rotated 45° from the polarization state of the third polarized signal. Suitable non-reciprocal polarization rotators 150 include, but are not limited to, non-reciprocal polarization rotators such as a Faraday rotator.

[0119] The combined effect of the polarization state rotation by the non-reciprocal polarization rotator 150 and the 45° polarization rotator 152 in the second component assembly 158 is that the polarization state of the fourth rotated signal is rotated 90° relative to the polarization state of the second polarized signal. Thus, in the illustrated example, the fourth rotated signal has the first polarization state.

[0120] When the non-reciprocal polarization rotator 150 in the first component assembly 156 and the non-reciprocal polarization rotator 150 in the first component assembly 158 are each Faraday rotators, the adapter component can include a magnet 160 arranged to provide a magnetic field that provides the desired functionality for the Faraday rotator.

[0121] The second component assembly 158 can include a 90° polarization rotator 162 that receives the fourth rotated signal and outputs a fifth rotated signal. In some examples, the 90° polarization rotator 162 is configured to rotate the polarization state of the first rotated signal by n*90°+90°, where n is 0 or an even integer. As a result, the polarization state of the fifth rotated signal is rotated 90° from the polarization state of the fourth rotated signal. The combined effect of the polarization state rotation by the non-reciprocal polarization rotator 150, the 45° polarization rotator 152, and the 90° polarization rotator 162 is that the polarization state of the fifth rotated signal is rotated 0° relative to the polarization state of the second rotated signal. Thus, in the illustrated example, the fifth rotated signal has the second polarization state. Suitable 90° polarization rotators 162 include, but are not limited to, reciprocal polarization rotators, such as a half-wave plate.

[0122] If the second component assembly 158 has the same configuration as the component assembly 156 , then the 90° polarization rotator 162 may also be present in the component assembly 156 .

[0123] A first polarizing beam splitter 146 in a second component assembly 158 receives the fifth rotated signal. The first polarizing beam splitter 146 is configured to split the received optical signal into an optical signal of a first polarization state and an optical signal of a second polarization state. Since the fifth rotated signal is in the second polarization state and has no or substantially no components, in the first polarization state, the first polarizing beam splitter 146 outputs an outgoing circulator signal of the second polarization state. As shown in FIG. 8A, the outgoing circulator signal exits the circulator 142.

[0124] When the LIDAR system includes one or more optical components 20 in addition to the adapter, any optical component 20 can receive an outgoing circulator signal from the circulator 142. The optical components 20 can output a system output signal from the LIDAR system. When an object is present in the field of view, the object can reflect light from the system output signal. All or a portion of the reflected light can be returned to the LIDAR system in a system return signal. FIG. 8B shows the optical components 20 for channel C.2 8B shows the path of light from a system return signal carrying the .DELTA..times ...

[0125] If the LIDAR system includes one or more optical components 20 in addition to the adapter, the system return signal is received by any of the optical components 20. The one or more optical components output a circulator return signal that is received by the oscillator. If the LIDAR system does not include any optical components 20 in addition to the adapter, the system return signal functions as the circulator return signal that is received by the oscillator.

[0126] The circulator return signal is received by a first polarizing beam splitter 146 in a second component assembly 158. As mentioned above, a possible result of using one or more lasers is that the system output signal is linearly polarized. For example, the light carried by the system output signal is all or substantially all in a first polarization state or a second polarization state. Reflection of the system output signal by an object may change the polarization state of all or a portion of the light in the system output signal. Thus, the system return signal may include light of different linear polarization states. For example, the system return signal may have a first contribution from light of a first polarization state and a second contribution from light of a second polarization state. The first polarizing beam splitter 146 may be configured to separate the first and second contributions. For example, the first polarizing beam splitter 146 may be configured to output a first split signal 168 carrying light of the first polarization state and a second split signal 170 carrying light of the second polarization state.

[0127] A second polarizing beam splitter 148 in a second component assembly 158 receives the first split signal and reflects the first split signal. A non-reciprocal polarization rotator 150 in the second component assembly 158 receives the first split signal and outputs a first FPSS signal. FPSS stands for first polarization state source, indicating that light that was in the first polarization state after reflection by an object was the light source for the first FPSS signal.

[0128] The first split signal travels in the opposite direction to the third rotated signal through the non-reciprocal polarization rotator 150. As a result, the non-reciprocal polarization rotator 150 is configured to rotate the polarization state of the first split signal by -n*90°-45°. Thus, the polarization state of the first FPSS signal is rotated -45° from the polarization state of the first split signal.

[0129] The 45° polarization rotator 152 in the second component assembly 158 receives the first FPSS signal and outputs a second FPSS signal. Because the 45° polarization rotator 152 is a reciprocal polarization rotator, the 45° polarization rotator 152 is configured to rotate the polarization state of the first FPSS signal by m*90°+45°, where m is 0 or an even integer. As a result, the polarization state of the second FPSS signal is rotated 45° from the polarization state of the first FPSS signal. The combined effect of the polarization state rotation by the non-reciprocal polarization rotator 150 and the 45° polarization rotator 152 in the second component assembly 158 is that the second FPSS signal is rotated 0° from the polarization state of the first split signal. As a result, the second FPSS signal has the first polarization state.

[0130] The second FPSS signal is received by a third polarizing beam splitter 154, which reflects the second FPSS signal so that it exits the circulator 142. The adapter components may include one or more beam steering units. The illustrated adapter includes a first beam steering unit 172. After exiting the circulator 142, the second FPSS signal is received by the first beam steering unit 172, which is configured to change the direction of travel of the second FPSS signal. Suitable first beam steering units 172 include, but are not limited to, mirrors and right angle prism reflectors.

[0131] The second FPSS signal travels from the first beam steering portion 172 to the beam directing portion 86 of the input port 72. The second FPSS signal can thus serve as a LIDAR input signal received by the LIDAR chip. Light from the LIDAR input signal travels through the input port 72 to one of the input waveguides 74 disclosed in the context of Figures 1B-2D.

[0132] The 90° polarization rotator 162 in the second component assembly 158 receives the second split signal 170 and outputs the first SPSS signal. SPSS stands for source of the second polarization state, indicating that the light that was in the second polarization state after reflection by an object was the source of light for the first SPSS signal. Since the 90° polarization rotator 162 is a reciprocal polarization rotator, the 90° polarization rotator 162 is configured to rotate the polarization state of the second split signal 170 by n*90°+90°, where n is 0 or an even integer. As a result, the polarization state of the first SPSS signal is rotated by 90° from the polarization state of the second split signal 170. Thus, in the illustrated example, the first SPSS signal has a first polarization state.

[0133] A non-reciprocal polarization rotator 150 in a second component assembly 158 receives the first SPSS signal and outputs a second SPSS signal. The first SPSS signal travels through the non-reciprocal polarization rotator 150 in the opposite direction to the third rotated signal. As a result, the non-reciprocal polarization rotator 150 is configured to rotate the polarization state of the first SPSS signal by -n*90°-45°. Thus, the polarization state of the second SPSS signal is rotated -45° from the polarization state of the first SPSS signal.

[0134] The 45° polarization rotator 152 in the second component assembly 158 receives the second SPSS signal and outputs a third SPSS signal. Since the 45° polarization rotator 152 is a reciprocal polarization rotator, the 45° polarization rotator 152 is configured to rotate the polarization state of the second SPSS signal by m*90°+45°, where m is 0 or an even integer. As a result, the polarization state of the third SPSS signal is rotated by 45° from the polarization state of the second SPSS signal. The combined effect of the polarization state rotation by the non-reciprocal polarization rotator 150 and the 45° polarization rotator 152 in the second component assembly 158 is that the third SPSS signal is rotated by 0° from the polarization state of the first SPSS signal. Additionally, the combined effect of the polarization state rotation by the non-reciprocal polarization rotator 150, the 45° polarization rotator 152, and the 90° polarization rotator 162 in the second component assembly 158 is that the third SPSS signal is rotated 90° from the polarization state of the second split signal 170. Thus, in the illustrated example, the third SPSS signal is shown in the first polarization state.

[0135] The third SPSS signal is received at a third polarizing beam splitter 154. The third polarizing beam splitter 154 reflects the third SPSS signal so that it exits the circulator 142. After exiting the circulator 142, the third SPSS signal may exit the adapter as shown in Figure 8B. In some examples, the third SPSS signal is discarded and / or ignored.

[0136] FIG. 8C shows channel C 38A and 8B. As disclosed in the context of FIGS. 2A-2D, the LIDAR output signals travel in different directions away from the LIDAR chip and / or beam directing section 86. Because the LIDAR output signals travel in different directions, the circulator input signals enter the first port 180 of the circulator 142 traveling in different directions. Although the different circulator input signals enter the circulator 142 traveling in different directions, the light from the different circulator input signals is processed by the same selection of circulator sections in the same order. For example, the light from the different circulator input signals travel through the components in the order disclosed in the context of FIGS. 8A and 8B. As a result, the light from the different circulator input signals exits the circulator at the second port 182. For example, the light from the different circulator input signals travels through the circulator ... 3 The optical path from the circulator input signal carrying channel C shows an output circulator signal exiting the circulator at second port 182. 3 Light from the circulator return signal carrying 2 Light from the circulator input signal carrying enters and exits the circulator at the second port 182, as described in the context of Figures 8A and 8B.

[0137] 8A and 8B shows that the output circulatory system signals approach the second port 182 from different directions and travel in different directions away from the circulator. The difference in direction of the output circulatory system signals can be due to the circulatory system input signals entering the circulator from different directions.

[0138] The circulator return signals return to the LIDAR system in the opposite direction to the outgoing circulator signal transmitting on the same channel. As a result, different circulator return signals return to the circulator from different directions. Thus, the light from the different circulator return signals can each travel a different path through the circulator.

[0139] The light in the different circulator return signal (source of first polarization state, FPSS) that was in the first polarization state after being reflected by the object exits the circulator 142 at a third port 184. For example, FIG. 8C shows a second FPSS signal (channel C) exiting the circulator from a third port 184. 3 8A and 8B, a second FPSS signal including light from a system return signal carrying channel C2 also exits the circulator at a third port 184.

[0140] The different second FPSS signals travel in different directions away from the circulator. The different second FPSS signals are received at different locations on the beam directing portion 86 of the input port 72. As a result, the light from the different second FPSS signals is directed to different alternate waveguides 16, as described in the context of Figures 2A-2D. For example, channel C 3 The light from the second FPSS signal carrying C 3 The first LIDAR input signal, denoted as 2 The light from the second FPSS signal carrying C 2 The first LIDAR input signal is denoted as C 3 The light from the LIDAR input signal, denoted as C 2Since light from the LIDAR input signals labeled as , , are received at different alternate waveguides 16, the alternate waveguides 16 receiving the LIDAR input signals may be a function of the direction in which the associated system output signal travels away from the LIDAR system and / or the direction in which the associated system return signal returns to the LIDAR system. Different second FPSS signals traveling in different directions away from the circulator may be the result of circulator input signals incident on the circulator from different directions. As a result, the alternate waveguides 16 receiving the LIDAR input signals may be a function of the direction in which the associated circulator input signal travels on the circulator and / or the direction in which the associated LIDAR output signal travels away from the LIDAR chip. Thus, the LIDAR system may be configured such that circulator input signals are incident on the circulator traveling in directions that cause the second FPSS signals to travel in different, non-parallel directions away from the circulator.

[0141] The light in the circulator return signal (source of the first polarization state, FPSS) that was in the second polarization state after being reflected by the object exits the circulator 142 at a fourth port 186. For example, FIG. 8C shows a third SPSS signal (channel C) exiting the circulator from the fourth port 186. 3 Similarly, channel C 2 The third SPSS signal, which includes light from the system return signal carrying the .alpha., also exits the circulator at the fourth port 186, as described in the context of Figures 8A and 8B. After exiting the circulator 142, the third SPSS signal may exit the adapter, as shown in Figure 8C.

[0142] The second FPSS signals can function as circulator output signals. The circulator output signals can include the first circulator output signals. Each second FPSS signal can function as one of the first circulator output signals. As a result, each first circulator output signal can include, primarily include, consist essentially of, and / or consist of light that was in a first polarization state (FPSS) when it was reflected by an object external to the LIDAR system.

[0143] A comparison of Figures 8A and 8C shows that the light from each circulator input signal is acted upon by the same selection of circulator sections (first selection) as it travels from the first port 180 to the second port 182. For example, the light from each circulator input signal is acted upon by the first polarizing beam splitter 146, the second polarizing beam splitter 148, the non-reciprocal polarization rotator 150, and the 45° polarization rotator 152 from the component assembly 156; also by the third polarizing beam splitter 154; and also by the 45° polarization rotator 152, the non-reciprocal polarization rotator 150, the second polarizing beam splitter 148, and the first polarizing beam splitter 146 from the second component assembly 158. However, Figures 8A and 8C also show that the light from each circulator input signal can travel different paths through the circulator. A comparison of FIG. 8B with FIG. 8C shows that the light in each first circulator output signal is operated by the same selection (second selection) of the circulator section when traveling from the second port 182 to the third port 184. However, FIG. 8B and FIG. 8C also show that the light in each first circulator output signal can travel different paths through the circulator. A comparison of FIG. 8B with FIG. 8C shows that the light in each second circulator output signal is operated by the same selection (third selection) of the circulator section when traveling from the second port 182 to the fourth port 186. However, FIG. 8B and FIG. 8C also show that the light in each second circulator output signal can travel different paths through the circulator. As is apparent from FIG. 8A-FIG. 8C, the first selection of parts, the second selection of parts, and the third selection of parts may be different.

[0144] Each of the output circulatory signals can include, primarily include, consist of, or consist essentially of light from one of the circulatory input signals. Also, each of the circulatory return signals can include, primarily include, consist of, or consist essentially of light from one of the circulatory input signals and one of the output circulatory signals. Furthermore, each of the circulatory output signals can include, primarily include, consist of, or consist essentially of light from one of the circulatory return signals, one of the output circulatory signals, and one of the circulatory input signals.

[0145] The polarizing beam splitter shown in Figures 8A-8C can have the structure of a cube beam splitter or a Wollaston prism. As a result, the components described as beam splitters can represent beam splitting portions such as coatings, plates, films, or interfaces between light-transmitting materials 190 such as glass, crystals, birefringent crystals, or prisms. The light-transmitting materials 190 can include one or more coatings arranged as needed. Examples of suitable coatings of the light-transmitting materials 190 include, but are not limited to, anti-reflective coatings. In some examples, one, two, three, or four ports selected from the group consisting of the first port 180, the second port 182, the third port 184, and the fourth port 186 are all or part of the surface of the circulator. For example, one, two, three, or four ports selected from the group consisting of first port 180, second port 182, third port 184, and fourth port 186 may each be all or a portion of a surface of optically transparent material 190, as shown in Figures 8A and 8B. The circulatory or optically transparent material 190 surface functioning as a port may include one or more coatings.

[0146] In some examples, the components of the component assembly 156, the second component assembly 158, and / or the circulator 142 are secured to one another with one or more adhesive media, such as glue, epoxy, or solder. In some examples, the components of the component assembly 156 and / or the second component assembly 158 are secured to one another prior to being included in the circulator 142. Using identically configured component assembly 156 and second component assembly 158 and securing the components of these component assemblies prior to assembling the circulator 142 can simplify manufacturing of the circulator.

[0147] Although the LIDAR system is disclosed as having the component assembly 156 and the second component assembly 158 of the same configuration, the component assembly 156 and the second component assembly 158 may have different configurations. For example, the component assembly 156 may include a 90° polarization rotator 162 that is not used during operation of the LIDAR system. As a result, the component assembly 156 may exclude the 90° polarization rotator 162. As another example, the component assembly 156 may include or consist of a non-reciprocal polarization rotator 150 and a 45° polarization rotator 152. In this example, the non-reciprocal polarization rotator 150 or the 45° polarization rotator 152 may directly receive the circulator input signal from the redirector 102. As a result, the component assembly 156 may exclude the first polarizing beam splitter 146, the second polarizing beam splitter 148, the associated light-transmitting material 190, and the 90° polarization rotator 162.

[0148] 9A is a schematic diagram of the relationship between a LIDAR system and a field of view. The field of view is represented by a dashed line extending from the LIDAR system to a virtual surface within the field of view. To illustrate the extent of the field of view, the virtual surface is located at a maximum operating distance (d M The maximum operating distance may generally be considered as the maximum distance at which the LIDAR system is configured to provide reliable LIDAR data. In practice, the virtual surface may have a curved shape due to the inherent nature of the maximum operating distance, but to simplify the following discussion, a plane is depicted.

[0149] The LIDAR system may include one or more beam steering mechanisms and one or more signal steering mechanisms, as described above. The electronics may operate the one or more beam steering mechanisms and the one or more signal steering mechanisms to steer the system output signal to different sample areas 129 in the field of view. Some of the sample areas are shown as rectangles on a plane in FIG. 9A. The electronics generate LIDAR data in a series of cycles by sequentially illuminating different sample areas in the field of view of the LIDAR system. LIDAR data may be generated for each sample area. A sample area is a portion of the field of view that is illuminated during a cycle used to generate the LIDAR data for that sample area. As a result, each LIDAR data result is associated with one of the cycles and one of the sample areas.

[0150] In FIG. 9A, the system output signal can continue to be scanned during the data period associated with the sample area, so that only a portion of the illustrated sample area is shown illuminated by the system output signal. For example, the system output signal in FIG. 9A can be scanned in the direction of the arrow labeled A during the period of a cycle. This scanning can cause the system output signal to illuminate the length of a plane labeled ct during the period of a cycle. Although the sample area is shown as two-dimensional in FIG. 9A, the sample area is three-dimensional and can extend from a rectangular shape on the illustrated plane to a LIDAR system.

[0151] FIG. 9B is a side view of the imaginary plane from FIG. 9A. The LIDAR system may include multiple steering mechanisms (not shown in FIGS. 9A-9C) that direct the system output signal to different sample areas within the field of view. The dashed lines in FIG. 9B indicate channel C. 2represents the path traveled by the center of gravity of a system output signal conveying a signal having a center of gravity of 138 across a plane in the field of view in response to steering of the system output signal solely by one or more beam steering units 138 (beam steering mechanism) as disclosed in the context of FIG. 7. The one or more beam steering units 138 provide two-dimensional steering of the system output signal. Sample area 129 is represented by a rectangle positioned along the path of the system output signal.

[0152] The scan path of the system output signal shown in Figure 9B has a fast axis, indicated by an arrow labeled "Fast" in Figure 9B. The scan path of the system output signal shown in Figure 9B has a slow axis, indicated by an arrow labeled "Slow" in Figure 9B. The scan rate of the system output signal in the direction of the fast axis is faster than the scan rate of the system output signal in the direction of the slow axis.

[0153] To obtain LIDAR data results that are representative of the entire field of view, it is generally desirable for the number of sample areas in the direction of the fast axis to match the number of sample areas in the direction of the slow axis. The scan rate in the fast direction can be increased to increase the number of zigzags that the system output signal travels across the field of view. Increasing the number of zigzags increases the number of sample areas in the direction of the fast axis. However, as applications of LIDAR systems increase, the desired size of the field of view and maximum operating distance increases to dimensions where the scan rate required for one or more beam steering components 138 is not possible or practical and / or has undesirably high power requirements.

[0154] FIG. 9C is a side view of the imaginary plane from FIG. 9A. The dashed line in FIG. 9C indicates the system output signal channel C. 29C represent paths that represent the center of gravity of the system output signal when it is steered solely by one or more beam steering units 138 (beam steering mechanism) disclosed in the context of FIG. 7. The sample regions in FIG. 9C are vertically separated from each other from the path provided by the beam steering mechanism, as indicated by the dashed lines. This vertical separation results from the electronics operating the signal directing unit 14 to change the direction in which the system output signal travels away from the LIDAR system. As a result, operation of the signal steering mechanism moves the system output signal in a direction that is transverse to the path provided by the beam steering mechanism. For example, the SR c1 The sample area 129 labeled 1 SR may represent the sample area when the signal guide 14 is operated to transmit c2 The sample area 129 labeled 2 can represent the sample area when transmitting SR; c3 The sample area 129 labeled 3 As is clear from the order of the sample fields shown in FIG. 9C, the signal guiding unit 14 steers the system output signal to the channel C in the order of i=l to N. i 9C shows the channel order being repeated in the same order, the channel order may be repeated in the reverse order from the previous order.

[0155] While maintaining the same frame rate (the rate at which each sample area in the field of view is illuminated by the system output signal), the scan rate on the fast axis can be reduced relative to the fast axis scan rate of FIG. 9B. For example, the fast axis scan rate of FIG. 9C is approximately 1 / N times the fast axis scan rate of FIG. 9B, where N is the number of alternate waveguides 16. The reduced fast axis scan rate is evident from the reduced number of zigzags within the same frame scan time (1 / frame rate). As a result of the reduced fast axis scan rate, the length of the sample area is shortened in the direction of the fast axis, and thus the size is reduced. The reduced size of the sample area improves the reliability of the LIDAR data.

[0156] In Figure 9B, the distance that the system output signal travels along the fast axis during each cycle is labeled ct. In Figure 9C, that same distance is labeled ct. Within each distance labeled ct in Figures 9B and 9C, there are 12 sample regions spanning across the slow axis. As a result, the combination of steering the system output signal using signal director 14 and a reduced fast axis scan rate can provide the same slow axis resolution as increasing the fast axis scan rate.

[0157] The fast axis scan rate (the rate at which the signal steering mechanism provides in the direction of the fast axis) can be expressed as the rate of angular change in the direction in which the system output signal travels away from the LIDAR system in the direction of the fast axis (the fast axis angular rate of change). The slow axis scan rate (the rate at which the signal steering mechanism provides in the direction of the slow axis) can be expressed as the rate of angular change in the direction in which the system output signal travels away from the LIDAR system along the slow axis (the slow axis angular rate of change). The slow and fast axes can be orthogonal to each other. In some examples, the ratio of the fast axis angular rate of change to the slow axis angular rate of change is greater than 1:1, 2:1, 3:1, or 4:1, and / or is less than 5:1, 10:1, or 100:1. Additionally or alternatively, the rate of change of angle of the fast axis may be greater than 100 deg / sec, 200 deg / sec or 300 deg / sec and / or less than 500 deg / sec, 1000 deg / sec or 2000 deg / sec and / or the rate of change of angle of the slow axis may be greater than 20 deg / sec, 50 deg / sec or 100 deg / sec and / or less than 200 deg / sec, 500 deg / sec or 1000 deg / sec.

[0158] 9B and 9C show the signal steering mechanism steering the system output signal back and forth on a zigzag path across the field of view, the signal steering mechanism can steer the system output signal back and forth in other patterns across the field of view. For example, the path need not include straight sections connected at sharp angles, but can instead include straight sections connected by curves. Alternatively, the path can include curves and / or curved sections and can exclude straight sections. For example, the path can be configured as a series of S-shaped sections.

[0159] 10A-10B show an example of a processing unit suitable for use as the processing unit 28 in a LIDAR system constructed according to FIGS. 1A-1C. In the LIDAR system of FIG. 1A, the signal directing unit 14 directs the outgoing LIDAR signal to a series of different alternative waveguides 16, as is evident from FIGS. 9A-9C. As a result, the comparison waveguide 26 receives a comparison signal that carries different channels in series (i.e., carries light from the outgoing LIDAR signal transmitted on the different alternative waveguides). Because the different channels illuminate different sample areas (FIGS. 9A-9C), the comparison waveguide 26 receives a comparison signal that carries light from the different sample areas in series. The comparison waveguide 26 transmits these comparison signals to the processing unit 28, which receives a comparison signal that carries different channels in series, and thus a comparison signal that carries light from the different sample areas in series. As mentioned above, the processing unit 28 also receives a reference signal from the reference waveguide 32.

[0160] In the LIDAR system of FIG. 1B, the second signal guide 76 guides the LIDAR input signals transmitted on the different input waveguides 74 to the comparison waveguide 26. However, the LIDAR input signals transmitting different channels are received on the different input waveguides 74. Furthermore, as a result of the signal guide 14 directing the outgoing LIDAR signals to one of the different alternative waveguides 16, the LIDAR input signals transmitting different channels are received in series on the input waveguides 74. As a result, the comparison waveguide 26 receives the LIDAR input signals transmitting different channels in series (i.e., transmitting light from the outgoing LIDAR signals transmitted on the different alternative waveguides). Because the different channels illuminate different sample regions, the comparison waveguide 26 receives a comparison signal transmitting light from the different sample regions in series. The comparison waveguide 26 transmits these comparison signals to a processing unit 28 so that the processing unit 28 receives comparison signals that serially transmit different channels, and therefore light from different sample regions. As mentioned above, the processing unit 28 also receives a reference signal from the reference waveguide 32.

[0161] The processing unit 28 includes an optoelectronic assembly configured to convert an optical signal to an electrical signal. Figure 10A is a schematic diagram of an example of a suitable optoelectronic assembly including a first splitter 200 that splits the comparison signal received from the comparison waveguide 26 onto a first comparison waveguide 204 and a second comparison waveguide 206. The first comparison waveguide 204 transmits a first portion of the comparison signal to an optical coupling portion 211. The second comparison waveguide 206 transmits a second portion of the comparison signal to a second optical coupling portion 212.

[0162] 10A also includes a second splitter 202 that splits the reference signal received from the reference waveguide 32 onto a first reference waveguide 210 and a second reference waveguide 208. The first reference waveguide 210 transmits a first portion of the reference signal to an optical coupling portion 211. The second reference waveguide 208 transmits a second portion of the reference signal to a second optical coupling portion 212.

[0163] The second optical combiner 212 combines the second portion of the comparison signal and the second portion of the reference signal into a second composite signal, which pulsates between the second portion of the comparison signal and the second portion of the reference signal due to a frequency difference between the second portion of the comparison signal and the second portion of the reference signal.

[0164] The second optical coupler 212 also splits the resulting second composite signal onto a first auxiliary detector waveguide 214 and a second auxiliary detector waveguide 216. The first auxiliary detector waveguide 214 transmits a first portion of the second composite signal to a first auxiliary optical sensor 218 that converts the first portion of the second composite signal into a first auxiliary electrical signal. The second auxiliary detector waveguide 216 transmits a second portion of the second composite signal to a second auxiliary optical sensor 220 that converts the second portion of the second composite signal into a second auxiliary electrical signal. Examples of suitable optical sensors include germanium photodiodes (PDs) and avalanche photodiodes (APDs).

[0165] In some examples, the second optical combiner 212 splits the second composite signal into the following: That is, the portion of the comparison signal included in the first portion of the second composite signal (i.e., the second portion of the comparison signal) is phase-shifted by 180° with respect to the portion of the comparison signal in the second portion of the second composite signal (i.e., the second portion of the comparison signal), but the portion of the reference signal in the second portion of the second composite signal (i.e., the second portion of the reference signal) is not phase-shifted with respect to the portion of the reference signal in the first portion of the second composite signal (i.e., the second portion of the reference signal). Alternatively, the second optical combiner 212 splits the second composite signal into the following: That is, the portion of the reference signal in the first portion of the second composite signal (i.e., the second portion of the reference signal) is phase shifted by 180° with respect to the portion of the reference signal in the second portion of the second composite signal (i.e., the second portion of the reference signal), but the portion of the comparison signal in the first portion of the second composite signal (i.e., the second portion of the comparison signal) is not phase shifted with respect to the portion of the comparison signal in the second portion of the second composite signal (i.e., the second portion of the comparison signal). Examples of suitable optical sensors include germanium photodiodes (PDs) and avalanche photodiodes (APDs).

[0166] The first optical combiner 211 combines the first portion of the comparison signal and the first portion of the reference signal into a first composite signal. Due to the frequency difference between the first portion of the comparison signal and the first portion of the reference signal, the first composite signal pulsates between the first portion of the comparison signal and the first portion of the reference signal.

[0167] The optical coupler 211 also splits the first composite signal onto a first detector waveguide 221 and a second detector waveguide 222. The first detector waveguide 221 transmits a first portion of the first composite signal to a first optical sensor 223 that converts the first portion of the second composite signal into a first electrical signal. The second detector waveguide 222 transmits a second portion of the second composite signal to a second optical sensor 224 that converts the second portion of the second composite signal into a second electrical signal. Examples of suitable optical sensors include germanium photodiodes (PDs) and avalanche photodiodes (APDs).

[0168] In some examples, the optical combiner 211 splits the first composite signal into the following: a portion of the comparison signal included in the first portion of the composite signal (i.e., the first portion of the comparison signal) is phase-shifted by 180° with respect to a portion of the comparison signal in the second portion of the composite signal (i.e., the first portion of the comparison signal), but a portion of the reference signal in the first portion of the composite signal (i.e., the first portion of the reference signal) is not phase-shifted with respect to a portion of the reference signal in the second portion of the composite signal (i.e., the first portion of the reference signal). Alternatively, the optical combiner 211 splits the composite signal into the following: a portion of the reference signal in the first portion of the composite signal (i.e., the first portion of the reference signal) is phase-shifted by 180° with respect to a portion of the reference signal in the second portion of the composite signal (i.e., the first portion of the reference signal), but a portion of the comparison signal in the first portion of the composite signal (i.e., the first portion of the comparison signal) is not phase-shifted with respect to a portion of the comparison signal in the second portion of the composite signal (i.e., the first portion of the comparison signal).

[0169] When the second optical combiner 212 splits the second composite signal such that the portion of the comparison signal in the first portion of the second composite signal is phase shifted by 180° relative to the portion of the comparison signal in the second portion of the second composite signal, the optical combiner 211 also splits the composite signal such that the portion of the comparison signal in the first portion of the composite signal is phase shifted by 180° relative to the portion of the comparison signal in the second portion of the second composite signal. When the second optical combiner 212 splits the second composite signal such that the portion of the reference signal in the first portion of the second composite signal is phase shifted by 180° relative to the portion of the reference signal in the second portion of the second composite signal, the optical combiner 211 also splits the composite signal such that the portion of the reference signal in the first portion of the composite signal is phase shifted by 180° relative to the portion of the reference signal in the second portion of the second composite signal.

[0170] The first reference waveguide 210 and the second reference waveguide 208 are constructed to provide a phase shift between the first portion of the reference signal and the second portion of the reference signal. For example, the first reference waveguide 210 and the second reference waveguide 208 can be constructed to provide a phase shift of 90° between the first portion of the reference signal and the second portion of the reference signal. As an example, one reference signal portion can be an in-phase component and the other reference signal portion can be a quadrature component. Thus, one of the reference signal portions can be a sine function and the other reference signal portion can be a cosine function. In one example, the first reference waveguide 210 and the second reference waveguide 208 are constructed such that the first reference signal portion is a cosine function and the second reference signal portion is a sine function. Thus, the portion of the reference signal in the second composite signal is phase shifted with respect to the portion of the reference signal in the first composite signal, but the portion of the comparison signal in the first composite signal is not phase shifted with respect to the portion of the comparison signal in the second composite signal.

[0171] The first light sensor 223 and the second light sensor 224 can be connected as a balanced detector, and the first auxiliary light sensor 218 and the second auxiliary light sensor 220 can also be connected as a balanced detector. For example, FIG. 10B shows a schematic diagram of the relationship between the electronics, the first light sensor 223, the second light sensor 224, the first auxiliary light sensor 218, and the second auxiliary light sensor 220. Although a photodiode symbol 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, one or more of these sensors can have other configurations. In some examples, the components shown in the schematic diagram of FIG. 10B are all included on the LIDAR chip. In some examples, the components shown in the schematic diagram of FIG. 10B are distributed between the LIDAR chip and electronics located away from the LIDAR chip.

[0172] The electronics connect the first light sensor 223 and the second light sensor 224 as a first balanced detector 225, and the first auxiliary light sensor 218 and the second auxiliary light sensor 220 as a second balanced detector 226. Specifically, the first light sensor 223 and the second light sensor 224 are connected in series. Also, the first auxiliary light sensor 218 and the second auxiliary light sensor 220 are connected in series. The series connection in the first balanced detector communicates with a first data line 228 that carries the output from the first balanced detector as a first data signal. The series connection in the second balanced detector communicates with a second data line 232 that carries the output from the second balanced detector as a second data signal. The first data signal is an electrical representation of the first composite signal, and the second data signal is an electrical representation of the second composite signal. Thus, the first data signal includes contributions from the first waveform and the second waveform, and the second data signal is a composite of the first and second waveforms. A portion of a first waveform in the first data signal is phase shifted relative to a portion of the first waveform in the first data signal, while a portion of a second waveform in the first data signal is in phase with a portion of the second waveform in the first data signal. For example, the second data signal includes a portion of a reference signal that is phase shifted relative to a different portion of the reference signal included in the first data signal. Also, the second data signal includes a portion of a comparison signal that is in phase with a different portion of a comparison signal included in the first data signal. The first and second data signals are pulsating as a result of the pulsation between the comparison signal and the reference signal, i.e., the pulsation in the first and second composite signals.

[0173] The electronics 62 includes a transform mechanism 238 configured to perform a mathematical transformation on the first and second data signals. For example, the mathematical transformation may be a complex Fourier transform with the first and second data signals as inputs. The first data signal is an in-phase component and the second data signal is a quadrature component, such that the first and second data signals together act as a complex data signal, where the first data signal is the real component of the input and the second data signal is the imaginary component of the input.

[0174] The conversion mechanism 238 includes a first analog-to-digital converter (ADC) 264 that receives a first data signal from the first data line 228. The first analog-to-digital converter (ADC) 264 converts the first data signal from an analog format to a digital format and outputs a first digital data signal. The conversion mechanism 238 includes a second analog-to-digital converter (ADC) 266 that receives a second data signal from the second data line 232. The second analog-to-digital converter (ADC) 266 converts the second data signal from an analog format to a digital format and outputs a second digital data signal. The first digital data signal is a digital representation of the first data signal and the second digital data signal is a digital representation of the second data signal. Thus, the first digital data signal and the second digital data signal together act as a composite signal, where the first digital data signal acts as a real component of the composite signal and the second digital data signal acts as an imaginary component of the composite data signal.

[0175] The conversion mechanism 238 includes a conversion unit 268 that receives the composite data signal. For example, the conversion unit 268 receives as an input a first digital data signal from a first analog-to-digital converter (ADC) 264 and also receives as an input a second digital data signal from a first analog-to-digital converter (ADC) 266. The conversion unit 268 may be configured to perform a mathematical transformation on the composite signal to convert it from the time domain to the frequency domain. The mathematical transformation may be a complex transformation, such as a complex Fast Fourier Transform (FFT). A complex transformation, such as a complex Fast Fourier Transform (FFT), appreciably shifts the frequency of the comparison signal relative to the system output signal.

[0176] The electronics include a LIDAR data generator 270 that receives and processes the output from the transform 268 to generate LIDAR data (distance and / or radial velocity between a reflecting object and the LIDAR tip or system). The LIDAR data generator performs peak finding on the output of the transform 268 to identify one or more peaks in the pulsation frequency.

[0177] The electronics use one or more frequency peaks to generate LIDAR data (distance and / or radial velocity between a reflecting object and the LIDAR chip or system) for further processing. The converter 268 can perform the attribution function using firmware, hardware, software, or a combination thereof.

[0178] FIG. 10C shows an example of the relationship between frequency, time, cycles, and data period of a system output signal. 0 ) may be the frequency of the system output signal at the start of the cycle.

[0179] FIG. 10C illustrates, in some examples, the cycle j and cycle j+i 10C shows frequency versus time for a sequence of two cycles labeled as 10 ...

[0180] Each cycle contains K data periods, each associated with a period index k, and the DP k In the example of FIG. 10C, each cycle is represented as DP k where k=1, 2, and 3. In some examples, the frequency vs. time pattern is the same for data periods that correspond to each other in different cycles, as shown in FIG. 10C. Corresponding data periods are data periods that have the same periodicity index. As a result, each data period DP 1 can be considered as the corresponding data period, and the associated frequency versus time pattern is the same in Figure 10C. At the end of the cycle, the electronics returns the frequency to the same frequency level that started the previous cycle.

[0181] Data Period DP 1 and data period DP 2 During the data period DP, the electronics operate the light source such that the frequency of the system output signal varies at a linear rate α. 1 The direction of frequency change during the data period DP 2 The direction of the frequency change is opposite to that of the

[0182] FIG. 10C shows the Rn k FIG. 10C shows the sample area Rn k and Rn k+1 Each sample area is illuminated with the system output signal during the data period shown in FIG. 10C as being associated with that sample area. For example, sample area Rn k DP 1 ~DP 3 A sample area index k can be assigned to the time. For example, the sample areas can be illuminated by the system output signal in the order indicated by the index k. As a result, the sample area Rn 10 is the sample region Rn 9 After the sample region Rn 11 The radiation can be irradiated before the irradiation.

[0183] LIDAR systems are typically configured to provide reliable LIDAR data when the object is within an operating distance range from the LIDAR system. The operating distance range can extend from a minimum operating distance to a maximum operating distance. A maximum round trip time can be the time required for a system output signal to leave the LIDAR system, travel the maximum operating distance to the object, and return to the LIDAR system, which in FIG. 10C is denoted as τ M It is written as follows.

[0184] Because there is a delay between the system output signal being transmitted and returning to the LIDAR system, the composite signal does not include a contribution from the LIDAR signal until after the system return signal has returned to the LIDAR system. Because the composite signal requires a contribution from the system return signal to be present at the LIDAR beating frequency, the electronics measure the LIDAR beating frequency resulting from the system return signal returning to the LIDAR system during a data window within the data period, the data window being labeled "W" in FIG. 10C. The contribution from the LIDAR signal to the composite signal is delayed by a maximum operating time delay (τ M ) As a result, the data window exists at a time greater than the maximum operating time delay (τ M ) to the end of the data period.

[0185] The frequency peaks in the output of the complex Fourier transform represent the pulsating frequencies of the complex signals, each of which includes a comparison signal that pulsates relative to a reference signal. The pulsating frequencies from two or more different data periods can be combined to generate the LIDAR data. For example, in FIG. 1 The beat frequency measured from the DP in FIG. 2 In combination with the beat frequency measured from the LIDAR data, the LIDAR data can be measured. 1 is applied during the data period to increase the frequency of the outgoing LIDAR signal such that ub = -f d +ατ, where f ub is the frequency given by the transformer, and f d is the Doppler shift (f d = 2νf c / c), where f c is the optical frequency (f 0), c represents the speed of light, v is the radial velocity between the reflecting object and the LIDAR system, where the direction from the reflecting object to the tip is assumed to be the positive direction, τ is the time it takes for light from the system output signal to travel to the object and back to the LIDAR system (round trip time), and c is the speed of light. The following equations are used to determine the time it takes for the electronics to receive the data period DP 2 is applied during the data period to reduce the frequency of the outgoing LIDAR signal such that db = -f d -ατ, where f db is the frequency given by the transformer (in this case, DP 2 f measured from i, LDP ) In these two equations, f d and τ are unknowns. The electronics solve these two equations for the two unknowns. The radial velocity of the sample volume is calculated by multiplying the Doppler shift (ν=c*f d / (2f c )) and / or the separation distance of the sample area can be calculated from c*τ / 2. As a result, the electronics use each beating frequency as a variable in one or more equations that generate LIDAR data. Because LIDAR data can be generated for each corresponding frequency pair output by the transform, separate LIDAR data can be generated for each object in the sample area. Thus, the electronics can measure multiple radial velocities and / or multiple radial separation distances from a single sampling of a single sample area in the field of view.

[0186] In Figure 1OC, DP 3 The data periods denoted as are optional. As mentioned above, there may be more than one object in the sample region. For example, the DP for cycle 2 1 During the feedback period in the DP for Cycle 2, 2 During the feedback period in the DP, two or more frequency pairs can be matched. 2 Which frequency peaks are in the DP 1It may be unclear which frequency peaks from the DP that correspond to the corresponding frequencies. As a result, it may be unclear which frequencies need to be used together to generate LIDAR data for an object in the sample volume. As a result, it is necessary to identify the corresponding frequencies. Identifying the corresponding frequencies can be performed such that the corresponding frequencies are from the same reflecting object in the sample volume. 3 The corresponding frequencies can be found using the data periods denoted as , and LIDAR data can be generated for each pair of corresponding frequencies and viewed and / or processed as LIDAR data for different reflective objects within the sample area.

[0187] In an example of identifying the corresponding frequency, as shown in FIG. 10C, a cycle includes three data periods (DP 1 , D.P. 2 and D.P. 3 When there are two objects in the sample area illuminated by the LIDAR output signal, the conversion unit converts the DP 1 Inside f ub Two different frequencies (f u1 and f u2 ) and DP 2 Inside f db for two different frequencies (f d1 and f d2 In this example, the possible frequency pairings are (f d1 , f u1 ), (f d1 , f u2 ), (f d2 , f u1 ), and (f d2 , f du2 ). f d and τ can be calculated for each possible frequency pairing. d For each pair of and τ, 3 =-f d +α 3 τ 0 , and calculate the theoretical f 3 It is possible to generate α 3 The value of DP1 and D.P. 2 In FIG. 10C, α is different from the α value used in 3 The value of is zero. In this case, the transformer also calculates f 3 The actual f 3 The theoretical f value closest to each 3 A frequency pair having a corresponding value is considered to be a corresponding pair. LIDAR data can be generated for each corresponding pair as described above and considered and / or processed as LIDAR data for a different reflecting object in the sample area. Each set of corresponding frequencies can be used in the above equation to generate LIDAR data. The generated LIDAR data will be for one of the objects in the sample area. As a result, a plurality of different LIDAR data values ​​can be generated for the sample area, with each different LIDAR data value corresponding to one of the different objects in the sample area.

[0188] The processing units in Fig. 1A and Fig. 1B receive a series of comparison signals transmitting different channels, and thus comparison signals from different sample areas. As a result, the processing units in Fig. 1A and Fig. 1B provide LIDAR data for a series of sample areas illuminated by the system output signals transmitting different channels. The series of sample areas for which the processing units provide LIDAR data may be the same as the series of illuminated sample areas. The configuration of the processing units in Fig. 10A-10C can also be used for the processing unit in Fig. 10C. However, the processing unit 28 in Fig. 1C receives a comparison signal transmitting only one of the channels. As a result, when the processing units 28 in Fig. 1A and Fig. 1B are the configuration of the processing units in Fig. 10A-10C, each processing unit provides LIDAR data for a series of sample areas illuminated by the system output signals transmitting only one channel.

[0189] In the LIDAR system of FIG. 1C, the electronics from the different processing units 28 can be combined such that the pulsating signals are electronically coupled rather than optically. For example, each processing unit 28 can include the opto-electrical assembly of FIG. 10A. FIG. 10D is a schematic diagram showing the relationship of the first optical sensor 223, the second optical sensor 224, the first auxiliary optical sensor 218, and the second auxiliary optical sensor 220 to the electronics in each opto-electrical assembly of FIG. 10A. Because each different processing unit 28 receives LIDAR input signals carrying different channels, FIG. 10D shows the first optical sensor 223, the second optical sensor 224, the first auxiliary optical sensor 218, and the second auxiliary optical sensor 220 associated with the channels received by the optical sensors.

[0190] The first data lines 228 from each of the different first balanced detectors 225 transmit the first data signals to the first electrical multiplexer 272, which outputs the first data signals from the different first data lines 228 on a common data line 273. Since the system output signals transmitting the different channels are output from the LIDAR system successively, the first LIDAR input signals transmitting the different channels are received on the first input waveguide 16 and the first LIDAR input signal successively. As a result, the processing unit 28 configured to receive the first comparison signal transmitting the channel i receives the first comparison signal in response to the signal directing unit 14 being operated such that the system output signal transmitting the channel i is output from the LIDAR system. Also, the processing unit 28 not configured to receive the first comparison signal transmitting the channel i does not substantially receive the first comparison signal in response to the signal directing unit 14 being operated such that the system output signal transmitting the channel i is output from the LIDAR system. Since the system output signals carrying different channels are output continuously from the LIDAR system, the first comparison signals carrying different channels are received continuously at the different processing units 28. However, some of the different channels that are generated may overlap. Since the processing units 28 receive the first comparison signals carrying different channels continuously, the first common data line 273 serially carries the first data signals carrying different channels. There may be some short-term overlap between channels in the series of first data signals, but not in the data window shown in FIG. 10C. The first common data line 273 carries the series of first data signals to the first analog-to-digital converter (ADC) 264.

[0191] The second data lines 232 from each of the different second balanced detectors 226 transmit the second data signals to a second electrical multiplexer 274. The second electrical multiplexer 274 outputs the second data signals from the different second data lines 232 on a second common data line 275. As described above, the processing unit 28 continuously receives the first comparison signals transmitting the different channels. As a result, the second common data line 275 transmits the second data signals transmitting the different channels in series. There may be some short-term overlap between the channels in the series of second data signals, but not between the data windows shown in FIG. 10C. The second common data line 275 transmits the series of second data signals to a second analog-to-digital converter (ADC) 266.

[0192] The conversion mechanism 238 and LIDAR data generator 270 of Figure 10D can operate as disclosed in the context of Figures 10A-10C. For example, a first analog-to-digital converter (ADC) 264 converts the first data signal from analog format to digital format and outputs a first digital data signal. A second analog-to-digital converter (ADC) 266 converts the second data signal from analog format to digital format and outputs a second digital data signal.

[0193] The first digital data signal and the second digital data signal carrying the same channel act together as a composite signal, with the first digital data signal acting as a real component of the composite signal and the second digital data signal acting as an imaginary component of the composite signal. The electronics are configured such that the first digital data signal and the second digital data signal carrying the same channel are received simultaneously by the LIDAR data generator 270. As a result, the LIDAR data generator 270 receives a composite signal carrying different channels in series. The LIDAR data generator 270 can generate LIDAR data for each of the different channels. As a result, the data generator 270 can generate LIDAR data for each sample area illuminated by a system output signal carrying a series of channels.

[0194] In another embodiment of the LIDAR system in which the relationship between the sensors in the photoelectric assembly from FIG. 10A and the electronics in the LIDAR system is constructed according to FIG. 10D, the electronics operates the electrical multiplexers as switches operated by the electronics. As a result, the electronics can operate the first electrical multiplexer 272 to select the first data signal to be output to the common data line 273 and the second electrical multiplexer 274 to select the second data signal to be output to the second common data line 275. As a result, the LIDAR system can be configured to simultaneously output system output signals carrying different channels. For example, the LIDAR chip can be configured to simultaneously output each of the LIDAR output signals carrying different channels. The signal directing unit 14 can be configured to direct the outgoing LIDAR system to one or more alternative waveguides 16. In an example in which the signal directing unit 14 is configured to direct the outgoing LIDAR system to all N alternative waveguides 16, the signal directing unit can be a signal splitter.

[0195] When the LIDAR system simultaneously outputs system output signals carrying different channels, each of the different processing units 28 can simultaneously receive a first LIDAR input signal carrying one of the channels. Thus, the first data lines 228 from each of the different processing units 28 simultaneously transmit a first data signal to the first electrical multiplexer 272. As a result, the first electrical multiplexer 272 simultaneously receives a plurality of first data signals, each carrying a different channel and originating from the different processing units 28. The electronics operates the first electrical multiplexer 272 using the switching function of the first electrical multiplexer 272, so that the first electrical multiplexer 272 outputs a first data signal carrying the different channels in series. As a result, the first common data line 273 transmits a first data signal carrying the different channels in series. Examples of suitable channel series include, but are not limited to, channel orders (numerical orders: i=l to i=N) with channel indexes i=1 to i=N.

[0196] The second data lines 232 from each of the different processing units 28 simultaneously transmit a second data signal to the second electrical multiplexer 274. As a result, the second electrical multiplexer 274 simultaneously receives a plurality of second data signals each transmitting a different channel and originating from the different processing units 28. The electronics use the switching function of the second electrical multiplexer 274 to operate the second electrical multiplexer 274, so that the second electrical multiplexer 274 outputs a second data signal transmitting the different channels in series. As a result, the second data lines 275 transmit a second data signal transmitting the different channels in series.

[0197] The conversion mechanism 238 and LIDAR data generator 270 of Figure 10D can operate as disclosed in the context of Figures 10A-10C. For example, a first analog-to-digital converter (ADC) 264 converts the first data signal from analog format to digital format and outputs a first digital data signal. A second analog-to-digital converter (ADC) 266 converts the second data signal from analog format to digital format and outputs a second digital data signal.

[0198] The first electrical multiplexer 272 and the second electrical multiplexer 274 are operated such that the first data line 273 and the second data line 275 simultaneously carry the same channel. As a result, the first digital data signal and the second digital data signal output from the first analog-to-digital converter (ADC) 264 and the second analog-to-digital converter (ADC) 266 simultaneously carry the same channel. The first digital data signal and the second digital data signal carrying the same channel act together as a composite signal, where the first digital data signal acts as the real component of the composite signal and the second digital data signal acts as the imaginary component of the composite signal. The first digital data signal and the second digital data signal carrying the same channel are simultaneously received by the LIDAR data generator 270. As a result, the LIDAR data generator 270 receives a composite signal carrying different channels in succession. The LIDAR data generator 270 can generate LIDAR data for each channel in the series of channels. As a result, the LIDAR data generator 270 can generate LIDAR data for each sample area illuminated by a system output signal carrying the series of channels.

[0199] When the LIDAR system simultaneously outputs system output signals transmitting different channels as described above, the system output signals travel in different directions away from the LIDAR system. As a result, the field of view will have multiple different sample areas simultaneously illuminated by different ones of the different system output signals. As an example, FIG. 9C shows a gSR c1 and gSR c2 The sample area is denoted as gSR. c1 and gSR c2 The sample area marked with is rSR c3 However, operation of the first electrical multiplexer 272 and the second electrical multiplexer 274 selects which channels are received by the LIDAR data generator 270. The LIDAR data generator 270 is c3 Upon receiving the signal generated from the illumination of the sample area denoted by gSR, the LIDAR data generator 270 c1 and gSR c2 As a result, the LIDAR data generator 270 does not receive a signal generated from illumination of the sample area denoted by rSR c3 Generates LIDAR data results for the sample area labeled as gSR c1 and gSR c2 14 does not generate LIDAR data results for the sample areas labeled "ghost sample areas." These sample areas effectively become ghost sample areas. As a result, one or more electrical multiplexers included in the LIDAR system select the sample areas for which the LIDAR data results are generated, rather than the output from the signal directing portion 14 which selects the sample areas for which the LIDAR data results are generated.

[0200] Although the LIDAR chip in FIG. 1A-FIG. 1C shows a single LIDAR core 4 on the LIDAR chip, the LIDAR chip can include multiple LIDAR cores. A LIDAR chip with multiple LIDAR cores 4 can have ports 18 arranged in a one-dimensional array or a two-dimensional array. As an example, FIG. 11A shows a LIDAR chip with six different cores, each of which can be constructed according to FIG. 1A. Each port 18 is shown as being constructed according to FIG. 2A. The ports 18 from the different cores are arranged in a 2X3 array. Each port exchanges optical signals with an alternate waveguide 16. An alternate waveguide 16 from the same core also exchanges optical signals with the pulsating signal generator 6 from one of these cores. As a result, the LIDAR chip can simultaneously generate LIDAR data for sample areas in six different fields of view. Additionally, the electronics can stitch together fields of view from different cores to create a composite field of view for the LIDAR system. As an example, FIG. 9D shows a composite field of view generated from the array of fields of view shown in FIG. 9C.

[0201] 11A shows the ports 18 spaced periodically in one dimension, the ports 18 can be spaced periodically in higher dimensions. In some examples, the ports 18 are arranged in a CxR array, where C is greater than or equal to 2, 4 or 8 and less than or equal to 32, 64 or 128, and / or R is greater than or equal to 2, 4 or 8 and less than or equal to 64, 32 or 128.

[0202] FIG. 11B shows a LIDAR chip with three different cores, each of which may be constructed according to FIG. 1B or FIG. 1C. As a result, each core includes a port 18 and an input port 72. Each of the ports 18 and input ports 72 are shown as being constructed according to FIG. 2A. Each input port 72 exchanges optical signals with an input waveguide 74. Alternative waveguides 16 and input waveguides 74 from the same core also exchange optical signals with a pulsating signal generator 6 from an associated core. As a result, the LIDAR chip can simultaneously generate LIDAR data for sample areas in three different fields of view. Although FIG. 11A shows ports 18 periodically spaced in one dimension, the ports 18 can be periodically spaced in a higher dimension. Additionally or alternatively, although FIG. 11A shows input ports 72 periodically spaced in one dimension, the input ports 72 can be periodically spaced in a higher dimension.

[0203] When pairs of ports 18 and corresponding input ports 72 are arranged in a C'xR' array, in some examples C' is 2, 4 or 8 or more and 64, 32 or 128 or less, and / or R' is 2, 4 or 8 or more and 64, 32 or 128 or less. In the example of FIG. 11B, C' is 1 and R' is 3. A C'xR' array can have ports 18 arranged in a CxR array and / or can have input ports 72 arranged in a CxR array. In the C'xR' of FIG. 11B, ports 18 are arranged in a 1x3 array and input ports 72 are arranged in a 1x3 array.

[0204] When the LIDAR chip includes multiple cores 4, each core 4 can have a light source 10 as shown in Figures 1A-1C. Alternatively, the light source can be the source of outgoing LIDAR signals at multiple different cores 4. Figure 12 shows a portion of a LIDAR chip with multiple different cores 4. The light source 10 outputs a common signal on a common waveguide 300. The common waveguide transmits the common signal to a signal splitter 302. The signal splitter 302 outputs multiple outgoing LIDAR signals, each received by a utility waveguide from a different one of the cores 4.

[0205] The signal splitter 302 can be a wavelength-independent splitter, such as an optical coupler, a Y-junction, an MMI, a cascaded evanescent optical coupler, and a cascaded Y-junction. As a result, each output LIDAR signal can have the same or substantially the same wavelength distribution. Thus, the system output signals from different cores 4 can have the same or substantially the same waveguiding distribution. Alternatively, the signal splitter 302 can be a wavelength-independent splitter, such as a demultiplexer. Suitable demultiplexers include, but are not limited to, arrayed waveguide gratings and echelle gratings. When the signal splitter 302 is a wavelength-independent splitter, the output LIDAR signals received by different cores can have different wavelength distributions. For example, the utility output LIDAR signals in different cores can carry different wavelength channels. As a result, the system output signals from different cores 4 can have the same or substantially the same waveguiding distribution.

[0206] Although FIGS. 1A-1C show the pulsating signal generating unit 6 and the transferring unit 8 on the same chip, the pulsating signal generating unit 6 and the transferring unit 8 may be on separate chips. For example, the pulsating signal generating unit 6 can be included in a pulsating signal generating chip, and the transferring unit 8 can be included in a transferring chip. As an example, FIG. 13A shows a pulsating signal generating chip including the pulsating signal generating unit 6 from the core 4 disclosed in the context of FIG. 1C. The alternative waveguide 16 terminates at a facet 304 where an optical signal can enter and exit the pulsating signal generating chip. Also, the input waveguide 74 terminates at a facet 304 where an optical signal can enter and exit the pulsating signal generating chip.

[0207] Although the pulsating signal-generating chip in Figure 13A shows a single core on the chip, the pulsating signal-generating chip can include multiple cores. As an example, Figure 13B shows a portion of a pulsating signal-generating chip that includes six cores, each core including three alternative waveguides 16. The alternative waveguides 16 from the different cores terminate at facets 304.

[0208] Figure 13C shows an example of a transfer chip. For example, Figure 13C shows a top view of a chip including ports 18 arranged as shown in Figure 11A. The portion of the alternative waveguide shown in Figures 1A-1C that is located on the transfer chip functions as a second alternative waveguide 310. The second alternative waveguide 310 terminates in a facet 304 located at the edge of the transfer chip.

[0209] FIG. 13D is a perspective view of a portion of the pulsatile signal generating chip shown in FIG. 13A or FIG. 13B. For example, FIG. 13D can represent a portion of the signal generating chip labeled D in FIG. 13A or FIG. 13B. The signal generating chip is constructed on a silicon-on-insulator wafer. The illustrated portion of the pulsatile signal generating chip includes a stop recess 330 sized to receive an edge of a transfer chip. The stop recess 330 extends through the optical transmission medium 94 into the base 81. In the illustrated form, the stop recess 330 extends through the optical transmission medium 94, the buried layer 90 and into the substrate 92.

[0210] The facets 304 on the pulsatile signal generating chip are positioned such that optical signals exiting the alternative waveguide 304 through the facets 304 can be received by a transfer chip positioned within the stop recess 330. Although not shown, the facets 304 of the alternative waveguide 16 may include an anti-reflective coating. Suitable anti-reflective coatings include single layer coatings such as, but not limited to, silicon nitride or aluminum oxide, or multi-layer coatings that may include silicon nitride, aluminum oxide, and / or silica.

[0211] One or more stops 332 extend upward from the bottom of the stop recess 330. For example, FIG. 13D illustrates two stops 332 extending upward from the bottom of the stop recess 330. The stops 332 include a cladding 334 disposed on a base portion 336. The substrate 92 can function as the base portion 336 of the stops 332, and the stops 332 can exclude the buried layer 92. The portion of the substrate 92 included in the stops 332 can extend from the bottom of the stop recess 330 to the level of the buried layer 90. For example, the stops 332 can be formed by etching the buried layer 90 and using the underlying substrate 92 as an etch stop. As a result, buried layer 90 defines the bottom of alternative waveguide 16, and the location of the top of base portion 336 relative to the optical mode of the optical signal in alternative waveguide 16 is known because the top of base portion 336 is located directly below buried layer 90. Cladding 334 may be formed on base portion 336 of stop 332, thereby providing stop 332 at a height that provides the desired alignment between alternative waveguide 16 and second alternative waveguide 310 on the transfer chip.

[0212] FIG. 13E is a perspective view of a portion of the transfer chip. For example, FIG. 13C can represent a portion of the transfer chip labeled T in FIG. 13C. The transfer chip is built on a silicon-on-insulator platform. FIG. 13E includes details not clearly shown in FIG. 13C. For example, to reduce image complexity, the slab region 98 defining the second alternative waveguide 310 is not shown in FIG. 13C.

[0213] Although not shown, facet 304 of second alternative waveguide 310 may optionally include an anti-reflective coating. Suitable anti-reflective coatings include single layer coatings such as, but not limited to, silicon nitride or aluminum oxide, or multi-layer coatings that may include silicon nitride, aluminum oxide, and / or silica.

[0214] The transfer tip also includes one or more alignment recesses 356 sized to receive the stops 332 from the pulsatile signal generating tip. The dashed lines in FIG. 13E show the depth and shape of one of the alignment recesses 356. In some examples, the alignment recesses 356 extend down to the buried layer 90. When the alignment recesses 356 extend down to the buried layer 90, the alignment recesses 356 can be formed by etching into the optical transmission medium 94 using an etch in which the buried layer 90 acts as an etch stop. In some examples, the alignment recesses 356 extend through the buried layer 90 to the top of the substrate 92. When the alignment recesses 356 extend down to the buried layer 90, the alignment recesses 356 can be formed by etching into the buried layer 90 using an etch in which the material of the substrate 92 acts as an etch stop. Whether the alignment recess 356 extends down to the buried layer 90 or to the substrate 92, the depth of the alignment recess 356 does not depend on the etch duration or other variables and is therefore consistent between different transfer chips. Also, because the alignment recess 356 extends down to the buried layer 90 or to the top of the substrate 94, the location of the bottom of the alignment recess 356 relative to the optical mode of the optical signal in the second alternative waveguide 310 is known since the buried layer 90 defines the bottom of the second alternative waveguide 310. As a result, said recess is suitable for vertically aligning the transfer chip with the pulsating signal generating chip.

[0215] The transfer chip can be flip-chip mounted on the pulsatile signal generating chip. For example, FIG. 13F shows a transfer chip constructed according to FIG. 13E flip-chip mounted on a signal generating chip constructed according to FIG. 13D. FIG. 13F is a cross-sectional view of the system through an alternative waveguide 16 on the pulsatile signal generating chip and a second alternative waveguide 310 on the transfer chip. FIG. 13F includes dashed lines to indicate features that are located behind other features in the system. For example, FIG. 13F includes dashed lines to indicate the location of portions of the stop 332 and alignment recess 356 that are located behind the ridge 96 of the alternative waveguide 16. FIG. 13F also includes dashed lines to indicate where the ridge 96 of the alternative waveguide 16 interfaces with the slab region 98 on the pulsatile signal generating chip, and where the ridge 96 of the second alternative waveguide 310 interfaces with the slab region 98 of the transfer chip.

[0216] The transfer tip is placed in a stop recess 330 on the pulsatile signal generating chip. The transfer tip is placed such that the second alternative waveguide 310 is located between the base 81 of the transfer tip and the base 81 of the pulsatile signal generating chip. The transfer tip is thus inverted in the stop recess 330. The transfer tip can be fixed to the pulsatile signal generating chip using solder or other adhesive.

[0217] The facet 304 of the alternative waveguide 16 is aligned with the facet 304 of the second alternative waveguide 310 so that the alternative waveguide 16 and the second alternative waveguide 310 can exchange optical signals. As shown by the line labeled A, the system provides a horizontal transition path in which the direction in which the optical signal travels between the pulsating signal generating chip and the transfer chip is horizontal or substantially horizontal. The horizontal direction can be the result of the facet 304 of the alternative waveguide 16 being perpendicular to the base 81 of the pulsating signal generating chip or substantially perpendicular to the base 81 of the pulsating signal generating chip and / or the facet 304 of the second alternative waveguide 310 being perpendicular to the base 81 of the transfer chip or substantially perpendicular to the base 81 of the transfer chip. In some examples, the facet 304 of the second alternative waveguide 310 is also perpendicular to the base 81 of the pulsating signal generating chip or substantially perpendicular to the base 81 of the pulsating signal generating chip. The top of facet 304 of second alternative waveguide 310 is at a level below the top of facet 304 of alternative waveguide 16. For example, facet 304 of alternative waveguide 16 and first facet 304 of second alternative waveguide 310 each have a higher elevation than a plane on the pulsating signal generating chip. The elevation of the top of facet 304 of alternative waveguide 16 relative to the plane is higher than the height of the top of facet 304 of second alternative waveguide 310 relative to the plane. Examples of horizontal surfaces of the pulsating signal generating chip include the top surface of base 81, the bottom surface of base 91, the top surface of substrate 92, and / or the bottom surface of substrate 92.

[0218] The facets 304 of the alternative waveguide 16 may be perpendicular or substantially perpendicular to the base 81 of the pulsating signal generating chip. Although not shown, the facets 304 of the alternative waveguide 16 may also be angled less than 90 degrees to the direction or propagation of the optical signal in the alternative waveguide 16. An angle less than 90 degrees may reduce the effects of back reflections in the alternative waveguide 16. The facets 304 of the second alternative waveguide 310 may be perpendicular or substantially perpendicular to the base 81 of the transfer chip and / or the base 81 of the pulsating signal generating chip. Although not shown, the facets 304 of the second alternative waveguide 310 may also be angled less than 90 degrees to the direction or propagation of the optical signal in the second alternative waveguide 310. An angle less than 90 degrees may reduce the effects of back reflections in the second alternative waveguide 310.

[0219] One or more stops 332 on the pulsatile signal generating tip are each received in one of the alignment recesses 356 on the transfer tip. The top of each stop 332 contacts the bottom of the alignment recess 356. As a result, the interaction between the stops 332 and the bottom of the alignment recess 356 prevents the transfer tip from moving further into the pulsatile signal generating tip. In some examples, the transfer tip rests on top of the stops 332.

[0220] As is evident from Fig. 13F, the facet 304 of the transfer chip is vertically aligned with the facet 304 of the alternative waveguide 16 on the pulsating signal generating chip. Also, the facet 304 of the transfer chip is horizontally aligned with the facet 304 of the alternative waveguide 16 on the pulsating signal generating chip. The horizontal orientation can be achieved by alignment of marks (not shown) and / or features on the transfer chip and the pulsating signal generating chip. As a result, the second alternative waveguide 310 on the transfer chip and the alternative waveguide 16 on the pulsating signal generating chip can exchange optical signals.

[0221] The vertical orientation can be achieved by controlling the height of the stop 332 on the pulsating signal generating chip. For example, the cladding 334 on the base portion 336 of the stop 332 can be grown to a height that places the first facet 304 of the second alternative waveguide 310 at a particular height relative to the facet 304 of the alternative waveguide 16 on the pulsating signal generating chip. As described above, the position of the bottom of the alignment recess 356 relative to the first facet 304 and / or the optical mode of the second alternative waveguide 310 is known. Also, the position of the top of the base portion 336 of the stop 332 relative to the alternative waveguide 16 and / or the optical mode in the alternative waveguide 16 is known. This information can be used to measure a thickness of the cladding 334 that provides the second alternative waveguide 310 with a desired vertical position relative to the alternative waveguide 16. The desired thickness of the cladding 334 can be precisely achieved by depositing one or more cladding layers using deposition techniques such as evaporation, plasma enhanced chemical vapor deposition (PECVD), and / or fumigation. As a result, one or more cladding layers can be deposited on the base portion 336 of the stop 332 to form the stop 332 to a height that provides the desired vertical orientation. Suitable materials for the layers of the cladding 334 include, but are not limited to, silica, silicon nitride, and polymers.

[0222] The above figures show the transfer tip located on the edge of the pulsatile signal generating chip, however, the transfer tip can be centrally located on the pulsatile signal generating chip.

[0223] Although a flip chip interface between the transfer chip and the pulsatile signal generating chip has the transfer chip received in a stop recess 330 on the pulsatile signal generating chip, this arrangement can be reversed. For example, the transfer chip can have a stop recess 330 and the pulsatile signal generating chip can be received in a stop recess 330 on the transfer chip.

[0224] Although the interface between the transfer chip and the pulsating signal generating chip is disclosed in the context of a portion of each alternative waveguide 16 from the LIDAR chip disclosed in Figures 1A-1C being split between the transfer chip and the pulsating signal generating chip, the disclosed interface can be applied to the input waveguide 74. For example, a first portion of each input waveguide can be located on the pulsating signal generating chip and another portion of each input waveguide can be located on the transfer chip. The interface between different portions of the input waveguide can be constructed as disclosed in the context of Figures 13A-13F.

[0225] When the alternative waveguide 16 and / or the input waveguide 74 include a taper 112 as disclosed in the context of Figures 5A-5C, the use of a transfer chip and a pulsatile signal generating chip is desirable. It can be difficult to manufacture a chip with a taper in combination with other components of the photonic circuit disclosed in the context of Figures 1A-1C. The use of a transfer chip allows the taper to be manufactured separately from the other components of the photonic circuit, thus simplifying the manufacture of the LIDAR chip.

[0226] 7 and 8 show the optical components 20 exchanging optical signals with one of the cores. However, if the LIDAR chip includes multiple cores, one or more of the optical components 20 can exchange optical signals with all or some of the cores. As an example, FIG. 14 shows a modification of FIG. 7 such that the beam shaper 134, the sight 136, and one or more beam steering units 138 exchange optical signals with multiple different cores on the LIDAR chip. As another example, FIG. 25 shows a modification of FIG. 8 such that the adapter exchanges optical signals with all or some of the cores on the LIDAR chip. As a result, one or more of the optical components 20 can exchange optical signals with the ports 18 arranged in a one-dimensional or two-dimensional array and / or the input ports 74 arranged in a one-dimensional or two-dimensional array.

[0227] When the LIDAR chip includes multiple cores, each different core can have a different redirector 82. Alternatively, the LIDAR chip can include one or more redirectors 82 that receive optical signals from and / or for different cores. For example, Figures 24 and 25 show two redirectors 82, each of which receives optical signals from and / or for a different core. For example, Figure 25 shows a LIDAR chip that includes a redirector 82 that receives an outgoing LIDAR signal from a different core and a redirector 82 that receives an incoming LIDAR signal for a different core.

[0228] The light sensor interfaced with the waveguide on the LIDAR chip can be a component separate from and attached to the chip. For example, the light sensor can be a photodiode or an avalanche photodiode. Examples of suitable light sensor components include, but are not limited to, InGaAs PIN photodiodes or InGaAs APDs (avalanche photodiodes) manufactured by Hamamatsu, Hamamatsu, Japan. These light sensors can be centrally located on the LIDAR chip. Alternatively, all or a portion of the waveguide terminating in the light sensor can terminate in a facet located at the edge of the chip, and the light sensor can be attached to the edge of the chip on the facet such that the light sensor receives light passing through the facet. Using a light sensor that is a separate component from the chip is suitable for all or a portion of the light sensor selected from the group consisting of the first light sensor and the second light sensor.

[0229] As an alternative to a light sensor that is a separate component, all or a portion of the light sensor can be integrated with the chip. For example, examples of light sensors that interface with ridge waveguides on chips constructed from silicon-on-insulator wafers can be found in Optics Express Vol. 15, No. 21, 13965-13971 (2007); U.S. Patent No. 8,093,080 issued Jan. 10, 2012; U.S. Patent No. 8,242,432 issued Aug. 14, 2012; and U.S. Patent No. 6,108,472 issued Aug. 22, 2000, all of which are incorporated herein in their entirety. The use of a light sensor integrated with the chip is suitable for all or a portion of the light sensor selected from the group consisting of the first light sensor and the second light sensor.

[0230] Various optical switches suitable for use as one of the optical switches disclosed above can be constructed on a planar device optical platform, such as a silicon-on-insulator platform. Examples of suitable optical switches for integration into a silicon-on-insulator platform include, but are not limited to, a Mach-Zehnder interferometer and a cascaded Mach-Zehnder interferometer.

[0231] Electronics 62 for application in LIDAR systems include, but are not limited to, controllers that include or consist of analog circuitry, digital circuitry, processors, microprocessors, digital signal processors (DSPs), application specific integrated circuits (ASICs), computers, microcomputers, or any combination suitable for performing the above-mentioned operational, monitoring, and control functions. In some examples, the controller has access to a memory that contains instructions that are executed by the controller during the performance of the operational, control, and monitoring functions. Although the electronics are shown as a single component in a single location, the electronics may include multiple different components that are independent of each other and / or located in different locations. Also, as discussed above, all or a portion of the disclosed electronics may be included on a chip with the electronics integrated with the chip.

[0232] Components on the LIDAR chip may be fully or partially integrated with the LIDAR chip. For example, the integrated optical components may include or consist of a portion of the wafer from which the LIDAR chip is manufactured. A wafer that may serve as a platform for the LIDAR chip may include multiple layers of material. At least some of the different layers may be different materials. As an example, a silicon-on-insulator wafer including a buried layer 90 between a substrate 92 and an optical transmission medium 94 is shown in FIG. 3. The integrated on-chip components may be formed by defining the features of the components in the optical transmission medium 94 using etching and masking techniques. For example, the slabs 318 that define the waveguides and stop recesses may be formed in desired areas of the wafer using different etches of the wafer. As a result, the LIDAR chip includes a portion of the wafer, and each of the integrated on-chip components may include or consist of a portion of the wafer. Additionally, the integrated on-chip components may be configured such that the optical signals traveling through the components travel through one or more of the layers originally included in the wafer. 3 guides an optical signal from the wafer through optical transmission medium 94. The integrated component may optionally include materials other than those that were present on the wafer. For example, the integrated component may include reflective materials and / or cladding.

[0233] The components on the LIDAR adapter need not be integrated. For example, the components on the LIDAR adapter need not include material from the base 100 and / or the common mount. In some examples, all of the components on the LIDAR adapter and / or isolator adapter are separate from the base 140. For example, the components on the LIDAR adapter can be constructed such that optical signals processed by the LIDAR adapter and / or isolator adapter do not travel through any portion of the base 140.

[0234] The numerical designations first, second, third, etc. are used to distinguish between different features and components and do not indicate the order or presence of the lower numerically designated feature. For example, the second component can be present without the first component being present and / or the third step can be performed before the first step.

[0235] Other embodiments, combinations, and modifications of the present invention will occur to those skilled in the art in view of the present teachings. Accordingly, the present invention is to be limited only by the following claims, which claims, taken in conjunction with the above specification and accompanying drawings, include all such embodiments and modifications.

Claims

1. a photonic circuit chip including a plurality of cores, each core including a port through which an output optical signal passes to exit the photonic circuit chip; each core is configured to emit from the photonic circuit chip such that the emitted optical signal travels toward a position above or below the photonic circuit chip; each core configured to combine light from one of the output light signals with a reference signal to generate a signal that pulsates at a pulsating frequency; each core includes an optical switch and a plurality of alternative waveguides, the optical switch in each core being configured to direct an output optical signal for that core to any one of the alternative waveguides; the photonic circuit chip includes a port configured to receive the outgoing optical signal from any one of the alternative waveguides; the port is configured such that the outgoing optical signal travels through the port and exits the port traveling toward a location above or below the photonic circuit chip; the direction in which each of the output optical signals travels away from the port changes in response to a change in the alternative waveguide receiving the output optical signal; a photonic circuit chip, the port receiving the outgoing optical signal, the photonic circuit chip including a reflective surface configured to receive the outgoing optical signal and reflect the outgoing optical signal received by the port; and and electronic equipment that uses the pulsation frequency from the core to calculate data indicative of radial velocity and / or distance between the imaging system and one or more objects located outside the imaging system. an imaging system comprising:

2. The system of claim 1 , wherein the electronics calculates different data for each of the cores.

3. The system of claim 1 , wherein the ports are arranged in a one-dimensional or two-dimensional array on the photonic circuit chip.

4. The system of claim 3 , wherein the array is a periodic array.

5. The system of claim 1 , wherein the photonic circuit chip is built on a silicon-on-insulator platform.

6. The system of claim 1 , wherein each of the output optical signals from one of the ports is output from the photonic circuit chip.

7. 2. The system of claim 1, wherein the imaging system is configured to output system output signals each including light from a different one of the output light signals, and wherein the direction in which each of the system output signals travels away from the imaging system changes in response to a change in the alternate waveguide that receives the output light signal.

8. The system of claim 1 , wherein one or more optical components receive the output optical signal from the photonic circuit chip and output the system output signal.

9. The system of claim 8 , wherein the one or more optical components include a lens.

10. The system of claim 8 , wherein at least one of the one or more optical components receives the output optical signal from a plurality of different cores.

11. 9. The system of claim 8, wherein the one or more optical components include a beam steering device controlled by the electronics to adjust the direction of one or more system output signals output from the imaging system.

12. 1. An imaging system including a photonic circuit chip, the photonic circuit chip includes an optical switch and a plurality of alternate waveguides, the optical switch configured to direct an outgoing optical signal to any one of the alternate waveguides; and the photonic circuit chip includes a port configured to receive the outgoing optical signal from any one of the alternative waveguides, the port configured such that the outgoing optical signal travels through the port and exits the port traveling toward a position above or below the photonic circuit chip; the direction in which the outgoing optical signal travels away from the port changes in response to a change in the alternative waveguide receiving the switch signal; Imaging system.

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