Lidar transceiver, lidar system, and lidar chip

Abstract

To provide frequency modulated continuous wave light detection and ranging.SOLUTION: A LIDAR transceiver comprises: a light source input configured to receive a laser signal; a plurality of coherent cells; and an optical switch configured to switchably couple the light source input to the plurality of coherent cells. At least one of the coherent cells includes: an input port coupled to the optical switch; an optical antenna; and a splitter coupled between the input port and the optical antenna. The splitter is configured to: split a received portion of the laser signal into a local oscillator signal and a transmit signal, where the transmit signal is emitted through the optical antenna, and reflection of the transmit signal is received through the optical antenna as a reflected signal; and output a return signal that is a portion of the reflected signal.SELECTED DRAWING: Figure 5a

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority under 35 U.S.C. § 119(e) to U.S. Provisional Patent Application No. 62 / 826,528, filed March 29, 2019, U.S. Provisional Patent Application No. 62 / 826,536, filed March 29, 2019, U.S. Provisional Patent Application No. 62 / 845,147, filed May 8, 2019, U.S. Provisional Patent Application No. 62 / 845,149, filed May 8, 2019, U.S. Provisional Patent Application No. 62 / 849,807, filed May 17, 2019, and U.S. Provisional Patent Application No. 62 / 940,790, filed November 26, 2019, the entire contents of which are incorporated by reference.

[0002] This disclosure relates generally to frequency modulated continuous wave (FMCW) light detection and ranging (LIDAR), and more specifically to switchable coherent pixel arrays for FMCW LIDAR. [Background technology]

[0003] Existing LIDAR systems use mechanical moving parts to direct the laser beam and are bulky, costly and unreliable in many applications (e.g., automotive). Summary of the Invention [Means for solving the problem]

[0004] The FMCW LIDAR transceiver is implemented in a photonic integrated circuit (PIC). The FMCW LIDAR transceiver performs optical beam steering in at least one dimension via a switchable coherent pixel array. In some embodiments, the FMCW LIDAR transceiver is part of a LIDAR chip that includes multiple FMCW LIDAR transceivers arranged in an array (e.g., a linear array, a two-dimensional array, etc.). The FMCW LIDAR transceiver and / or the LIDAR chip can be part of an FMCW LIDAR system. The FMCW LIDAR system determines depth information about the transceiver's field of view (e.g., distance to objects in the transceiver's field of view, velocity of the objects, etc.).

[0005] In some embodiments, the FMCW LIDAR transceiver includes one or more subarrays. The subarray may include an input port, an optical switch, a plurality of splitters, a plurality of mixers, and a plurality of antennas. The input port is configured to receive a frequency modulated laser signal. The optical switch is configured to switchably couple the input port to an optical antenna and form an optical path between the input port and the optical antenna. For each optical path from the input port to one of the optical antennas, a splitter from the plurality of splitters is coupled along the optical path. Each splitter is configured to split a received portion of the laser signal into a local oscillator signal and a transmitted signal. The transmitted signal is emitted via the optical antenna, and a reflection of the transmitted signal is received as a reflected signal via the optical antenna. The splitter also outputs a return signal that is a portion of the reflected signal. For each splitter, a mixer from the plurality of mixers is coupled to receive the return signal and the local oscillator signal from the splitter. The mixer is configured to mix the return signal and the local oscillator signal to generate one or more output signals used to determine depth information about the field of view of the transceiver.

[0006] In some embodiments, the FMCW LIDAR system includes a LIDAR chip. The LIDAR chip includes an FMCW LIDAR transceiver implemented in an optical integrated circuit. The optical integrated circuit includes one or more subarrays. The subarray may include an input port, an optical switch, a plurality of splitters, a plurality of mixers, and a plurality of antennas. The input port is configured to receive a frequency modulated laser signal. The optical switch is configured to switchably couple the input port to the optical antenna and form an optical path between the input port and the optical antenna. For each optical path from the input port to one of the optical antennas, one of the plurality of splitters is coupled along the optical path. Each splitter is configured to split a received portion of the laser signal into a local oscillator signal and a transmitted signal. The transmitted signal is emitted via the optical antenna, and a reflection of the transmitted signal is received as a reflected signal via the optical antenna. The splitter also outputs a return signal that is a portion of the reflected signal. For each splitter, one of the multiple mixers is coupled to receive the return signal and the local oscillator signal from the splitter. The mixer is configured to mix the return signal and the local oscillator signal to generate one or more output signals that are used to determine depth information about the field of view of the FMCW LIDAR system. The FMCW LIDAR system also includes a lens positioned to collimate the transmitted signals emitted via the multiple antennas. The lens is also positioned to receive the reflected signal and couple it to an optical antenna that emits the reflected signal. [Brief description of the drawings]

[0007] Embodiments of the present disclosure have other advantages and features that will become more clearly apparent from the following detailed description and the appended claims when taken in conjunction with the accompanying drawings, in which:

[0008] [Figure 1]FIG. 1 illustrates a schematic diagram of a switchable coherent pixel array FMCW LIDAR chip in accordance with one or more embodiments.

[0009] [Figure 2a] 1 illustrates four versions of a coherent pixel in accordance with one or more embodiments. [Figure 2b] 1 illustrates four versions of a coherent pixel in accordance with one or more embodiments. [Figure 2c] 1 illustrates four versions of a coherent pixel in accordance with one or more embodiments. [Figure 2d] 1 illustrates four versions of a coherent pixel in accordance with one or more embodiments.

[0010] [Figure 3a] 1 illustrates a switchable coherent pixel array according to one or more embodiments in which an optical coherent detection block is shared among multiple coherent pixels. [Figure 3b] 1 illustrates a switchable coherent pixel array according to one or more embodiments in which an optical coherent detection block is shared among multiple coherent pixels. [Figure 3c] 1 illustrates a switchable coherent pixel array according to one or more embodiments in which an optical coherent detection block is shared among multiple coherent pixels.

[0011] [Figure 4a] 1 and 3a show examples of the active optical switches. [Figure 4b] 1 and 3a show examples of the active optical switches. [Figure 4c] 1 and 3a show examples of the active optical switches.

[0012] [Figure 5a]1 illustrates how a switchable coherent pixel array can direct a light beam for FMCW LIDAR operation in accordance with one or more embodiments. [Figure 5b] 1 illustrates how a switchable coherent pixel array can direct a light beam for FMCW LIDAR operation in accordance with one or more embodiments. [Figure 5c] 1 illustrates how a switchable coherent pixel array can direct a light beam for FMCW LIDAR operation in accordance with one or more embodiments.

[0013] [Figure 6] 1 illustrates a LIDAR chip having multiple parallel FMCW LIDAR transceivers arranged in a linear fashion in accordance with one or more embodiments.

[0014] [Figure 7a] 1 illustrates an example of mechanically assisted laser beam scanning in a switchable coherent pixel array based FMCW LIDAR system according to one or more embodiments. [Figure 7b] 1 illustrates an example of mechanically assisted laser beam scanning in a switchable coherent pixel array based FMCW LIDAR system according to one or more embodiments. [Figure 7c] 1 illustrates an example of mechanically assisted laser beam scanning in a switchable coherent pixel array based FMCW LIDAR system according to one or more embodiments.

[0015] [Figure 8] 1 illustrates a diagram of a first embodiment of a coherent pixel that uses two polarizations of light to improve the performance of an FMCW LIDAR system in accordance with one or more embodiments.

[0016] [Figure 9]1 illustrates a diagram of a second embodiment of a coherent pixel that uses two polarizations of light to improve the performance of an FMCW LIDAR system in accordance with one or more embodiments.

[0017] [Figure 10] 1 illustrates a method of using coherent pixels in a focal plane array for FMCW applications in accordance with one or more embodiments.

[0018] [Figure 11a] 1 illustrates an electrical wiring scheme for a switchable coherent pixel array according to one or more embodiments. [Figure 11b] 1 illustrates an electrical wiring scheme for a switchable coherent pixel array according to one or more embodiments. [Figure 11c] 1 illustrates an electrical wiring scheme for a switchable coherent pixel array according to one or more embodiments. [Figure 11d] 1 illustrates an electrical wiring scheme for a switchable coherent pixel array according to one or more embodiments.

[0019] [Figure 12] 1 illustrates a system diagram of a switchable coherent pixel array based FMCW LIDAR system in accordance with one or more embodiments. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] The FMCW LIDAR system determines depth information (e.g., distance, velocity, acceleration for one or more objects) for the field of view of the system. The FMCW LIDAR system uses a switchable coherent pixel array (SCPA) on a LIDAR chip (e.g., an integrated optical circuit). The LIDAR chip may include one or more FMCW transceivers on the LIDAR chip (e.g., each FMCW transceiver may be responsible for a different angular field of view within the field of view of the LIDAR system). The FMCW LIDAR system splits the FMCW beam into a signal portion and a mixed portion. The signal portion is conditioned through a lens assembly and output within the field of view of the FMCW LIDAR system. The signal portion reflects off one or more objects in the field of view to form a reflected signal, and reflections of the signal portion are detected by the FMCW LIDAR system. A portion of the reflected signal is mixed with the mixed portion of the beam to directly measure the distance and velocity of one or more objects within the field of view of the FMCW LIDAR system.

[0021] The FMCW LIDAR system transceiver is implemented on an optical integrated circuit. The optical integrated circuit includes one or more subarrays of basic functions. Each subarray includes an input port, an optical switch, a number of splitters, a number of mixers, and a number of antennas. The input port is configured to receive a frequency modulated laser signal. The frequency modulated laser signal may be external to the transceiver or, in some cases, on the same chip as the optical integrated circuit. The optical switch is configured to switchably couple the input port to the optical antenna and form an optical path between the input port and the optical antenna. In some embodiments, the optical switch optically couples the frequency modulated laser signal to each of the optical antennas one at a time during a scanning period of the FMCW transceiver.

[0022] For each optical path from the input port to one of the optical antennas, a splitter from the plurality of splitters is coupled along the optical path. Each splitter is configured to split a received portion of the laser signal into a local oscillator signal and a transmitted signal. The transmitted signal is emitted via the optical antenna, and a reflection of the transmitted signal is received via the optical antenna as a reflected signal. The splitter also outputs a return signal that is a portion of the reflected signal. For each splitter, a mixer from the plurality of mixers is coupled to receive the return signal and the local oscillator signal from the splitter. The mixer is configured to mix the return signal and the local oscillator signal to generate one or more output signals. A frequency of a beat tone resulting from the mixing is proportional to a distance from the LIDAR system to a light-reflecting surface. The one or more output signals are used to determine depth information about a field of view of the LIDAR system. Depth information describes the distance to various surfaces in the field of view of the LIDAR system and may also include information describing the velocity of objects in the field of view of the LIDAR system.

[0023] It should be noted that the LIDAR chip can steer the light emitted from the LIDAR system in at least one dimension. Also, in some embodiments, the optical antennas are arranged in two dimensions to allow the LIDAR chip to steer the light beam in two dimensions. The ability to steer the beam without moving parts can alleviate form factor, cost, and reliability issues found in many existing mechanically driven LIDAR systems.

[0024] FIG. 1 shows a schematic diagram of a switchable coherent pixel array (SCPA) FMCW LIDAR chip 11 according to one or more embodiments. The LIDAR chip is an optical integrated circuit. The chip may include multiple basic functional subarrays 100. Each subarray 100 includes optical input / output (I / O) ports 102 and optional 1-K optical splitters 103 (K is an integer) and one or more SCPAs 101. The 1-K optical splitters 103 may be passive or active. Each optical I / O is supplied by a frequency modulated light source provided by an off-chip or on-chip laser. To reduce the number of optical I / Os, optical power may be distributed on-chip via the optional 1-K optical splitters. In the illustrated embodiment, each output of the 1-K optical splitters 103 is supplied to a corresponding SCPA 101. In the illustrated embodiment, each SCPA 101 includes M coherent pixels 105 (M is an integer) and an optical switch network 104. It should be noted that in some cases one or more of the optical switch networks 104, optional 1-K optical splitters 103, or some combination thereof may simply be referred to as an optical switch. The optical switch is configured to switchably couple the input ports 102 to the optical antennas in the coherent pixels and form optical paths between the input ports and the optical antennas. The optical switch may include multiple active optical splitters. In some embodiments, the optical switch optically couples a frequency modulated laser signal to each of the optical antennas one at a time during a scanning period of the FMCW transceiver.

[0025] The optical switch network 104 selects one or more of the M coherent pixels to transmit and receive frequency modulated (FM) light for distance measurement and detection. The coherent pixels may be physically arranged on the chip in a one-dimensional array (e.g., a linear array) or a two-dimensional array (e.g., a rectangular, regular shape (e.g., a non-random arrangement such as a grid)). In some embodiments, the selected coherent pixel may transmit light into free space, receive the returning optical signal, perform coherent detection, and directly convert the optical signal to an electrical signal for digital signal processing. It should be noted that instead of propagating again through the switch network for detection, the received optical signal is output individually routed (not shown in the illustrated embodiment), thereby reducing losses and correspondingly improving the quality of the signal.

[0026] 2a-2d illustrate four versions of a coherent pixel according to one or more embodiments. The four versions of the coherent pixel may be, for example, the embodiments of the coherent pixel described above in FIG. 1. In FIG. 2a and FIG. 2b, light from an optical switch network (e.g., optical switch network 104) is provided to an optical input port 203 of the coherent pixel. A bidirectional optical 2×2 splitter 202 splits the light into two output ports, called TX signal 205 and local oscillator 206 (LO). The TX signal 205 is transmitted from the chip using an optical antenna 200. An optical antenna is a device that launches light from an on-chip waveguide into free space or couples light from free space into an on-chip waveguide, such as a grating coupler, edge coupler, integrated reflector, or any spot size converter. An optical antenna may be polarization sensitive, usually with a much higher launch / coupling efficiency for light with one particular polarization (e.g., TE). Since the antenna is reciprocal, it collects the reflected beam from the object under test and returns it to the bidirectional 2x2 splitter 202, which splits it again between ports 203, 204. The bidirectional optical 2x2 splitter 202 acts as a "Pseudo Circulator" in such a monostatic configuration where the transmitter and receiver are collocated. The signals received at ports 204 and LO 206 are mixed for coherent detection by an optical mixer, which can be a balanced 2x2 optical coupler 201 as in FIG. 2a or an optical hybrid 209 as in FIG. 2b. Finally, a pair of photodiodes 207 (PD) in FIG. 2a and four PDs in FIG. 2b convert the optical signals to electrical signals for beat tone detection. The version in FIG. 2a is called the balanced photodiode (BPD) version and the version in FIG. 2b is called the hybrid version. The hybrid version provides in-phase and quadrature outputs (I / Q) that can be used to resolve velocity-distance ambiguities or enable advanced DSP algorithms in FMCW LIDAR systems.Using a bidirectional optical 2x2 splitter as a "pseudo circulator", it is not necessary to provide an individual circulator for every single pixel, which is impractical for large arrays with hundreds of pixels. Thus, the coherent pixel can significantly reduce the signal-to-noise ratio (SNR) penalty cost and form factor by up to 6 dB (since some induced optical power is not available for coherent detection). For example, the received optical signal can be split between port 203 and port 204, with the latter port 204 being used for coherent detection. The coherent pixel design illustrated in Figures 2c and 2d solves these limitations by introducing a polarization splitting antenna 210 in a new structure. Light from the optical switch network is provided to the optical input port 203 of the coherent pixel. An optical splitter 212 splits the light into two output ports: TX signal 215 and local oscillator 214 (LO). The TX signal 215 is transmitted directly from the chip using the polarization splitting optical antenna 210 with one polarization (e.g., TM). The antenna collects the reflected beam from the measurement object and couples the orthogonal polarization (e.g., TE) into the waveguide 213, which sends it directly to the optical mixer. In this case, the optical signal received by the antenna is not further split by an additional splitter or "pseudo circulator". The signals received from the port 213 and the LO 214 are mixed for coherent detection by the optical mixer, which can be a balanced 2x2 optical combiner 201 as in FIG. 2c or an optical hybrid 209 as in FIG. 2d. Finally, a pair of photodiodes 207 (PD) in FIG. 2c and four PDs in FIG. 2d convert the optical signal to an electrical signal for beat tone detection. This design implements a highly efficient integrated circulator for every single coherent pixel, enabling an ultra-sensitive on-chip monostatic FMCW LIDAR. The details are further discussed in FIG. 8 to FIG. 10. In some embodiments, the coherent pixel of Figures 2a-2d in the aspect of Figure 1 has multiple optical antennas each having a separate splitter, each splitter configured to couple along a respective optical path between an optical switch and a corresponding antenna.

[0027] 3a-3c illustrate an SCPA according to one or more embodiments in which an optical coherent detection block is shared among multiple coherent pixels. As shown in FIG. 3a, the chip 11 may include multiple subarrays 100 of basic functions. Each subarray 100 includes an optical I / O port 102, an optional 1-K optical splitter 103, and one or more SCPAs 101. Each optical I / O is supplied by a frequency modulated light source provided by an off-chip or on-chip laser. Optical power may be distributed on-chip via the optional 1-K optical splitter 103 to reduce the number of optical I / Os. Each of the 1-K optical splitters is fed into a selective 1-N optical switch network 107 that selects one of N columns (N is an integer). Each column includes a coherent receiver block 306. The optical switch network 104 further selects one of M (M is an integer) antennas 105 to transmit and receive frequency modulated (FM) light for distance measurement and detection. The antennas may be physically arranged on the chip in a one-dimensional array (e.g., linear array) or two-dimensional array (e.g., rectangular array, regular array, etc.). In this design, the selected antenna transmits light into free space and passively receives the returned optical signal. The coherent detection function, including optical mixing and optical-to-electrical conversion, is performed in the coherent receiver block 306.

[0028] It should be noted that in some cases, one or more of the optical switch networks 104, the 1-N optical switch networks 107, or some combination thereof may simply be referred to as an optical switch. The optical switch is configured to switchably couple the input ports 102 to the optical antennas and form optical paths between the input ports and the optical antennas.

[0029] 3b and 3c are examples of coherent receiver blocks (e.g., coherent receiver block 306) that use a "pseudo circulator" and operate similarly to the coherent pixel blocks of FIGS. 2a and 2c. Unlike the scheme of FIG. 1, the received optical signal propagates again through a 1-M switch network to be detected by the coherent receiver block 306. Compared to the SCPA of FIG. 1, this design significantly reduces the number of photodiodes to reduce the number of electrical outputs, simplifying electrical routing and / or packaging. Also, the pixel size is significantly reduced to allow for smaller pitches between pixels, allowing for higher resolution FMCW LIDAR.

[0030] In some embodiments, in the coherent receiver block of FIGS. 3b and 3c in the embodiment of FIG. 3, there is only one splitter 202 coupled between the input port and the corresponding optical switch network 104 for each optical switch network 104.

[0031] 4a-c show an example of the active optical switch 104 of FIG. 1 and FIG. 3a. A Binary Tree Switch Network and its individual switch cells 401 are illustrated in FIG. 4a. A 50 / 50 optical splitter 400 feeds two optical phase shifters 402 that adjust the phase of each arm using control signals 403 and 404. The electrical control of the optical switch can be push-pull using two controllers or single-sided using only one controller. The optical signals of the two arms are combined using an optical 2×2 coupler 405. Depending on the control signals, constructive (destructive) interference occurs and the light is switched between the two outputs. The optical phase shifter 402 can be, but is not limited to, a thermal-optical phase shifter or an electro-optical phase shifter. As shown in FIG. 4b, the switch network can also be implemented with an array of micro-ring resonators 410 (MRRs). The MRR picks up the optical signal from the main bus waveguide only if the resonant frequency of the device is aligned with the laser wavelength. An electrical control signal sets the resonance of the MRR in the array, thus selecting the output port through which the FM signal is transmitted or received. Similarly, the switch network can also be implemented with an array of micro-electromechanical system (MEMS) switches, as shown in Figure 4c. The MEMS switches are configured to direct the light in the main bus waveguide, thus selecting the output port through which the FM signal is transmitted or received.

[0032] 5a-5c illustrate how an SCPA directs a light beam for FMCW LIDAR operation according to one or more embodiments. In this example, a single SCPA-based LIDAR transceiver 501 is used for illustration. The LIDAR transceiver 501 includes an FMCW light source input 502, an optical switch network 503, a coherent pixel cell 504, and one or more optical antennas 505. The LIDAR transceiver 501 can be, for example, the FMCW LIDAR chip 11 described above with reference to FIG. 1 and FIG. 3a. The coherent pixel cell 504 can be, for example, the coherent pixel 105 described above in relation to FIG. 1. In some embodiments, the coherent pixel cell 504 can be composed of the elements of FIG. 3a (e.g., the coherent receiver 304 includes one or more optical antennas and corresponding optical paths between them).

[0033] In the illustrated embodiment, the optical antenna of the LIDAR transceiver 501 is positioned at the focal length of the lens system 507. The lens system 507 includes one or more optical elements (e.g., positive lens, freedom lens, Fresnel lens, etc.) that map the physical location of each coherent pixel to a unique direction. In some embodiments, the lens system 507 is positioned to collimate the transmitted signal emitted through the multiple antennas. The lens system 507 is configured to project the transmitted signal emitted from any one of the multiple antennas onto a corresponding portion of the field of view of the scanner module and provide a reflected signal of the transmitted signal to the antenna. Each optical antenna transmits and receives light at a different angle. Thus, by switching to the other antenna, individual optical beam scanning is achieved, as shown in Figures 5b and 5c. In the case of FMCW LIDAR, the laser beam 508 scans across the target 509 in the field of view, and the coherent pixels of the LIDAR transceiver 501 generate electrical signals that are then digitally processed to generate the LIDAR point cloud. In some embodiments, lens system 507 generates a collimated transmitted signal that scans the transceiver field of view along one angular dimension (eg, as shown in Figures 5b and 5c).

[0034] As shown in Figures 5a-5c, the coherent pixel cells 504 are arranged in a linear array. However, in other embodiments, the coherent pixel cells 504 may have some other arrangement (e.g., two-dimensional, rectangular, etc.). It should be noted that in some embodiments, a two-dimensional arrangement may be used to emit multiple transmitted signals from multiple antennas (as described below in connection with Figure 12), so that the multiple transmitted signals scan a portion of the field of view of the scanner module in two dimensions. For example, scanning is performed in a first dimension and a second dimension, and the field of view of the scanner module is 5 degrees or more along the first dimension and 5 degrees or more along the second dimension.

[0035] FIG. 6 illustrates a LIDAR chip 606 having multiple parallel FMCW LIDAR transceivers 501 arranged in a linear array according to one or more embodiments. As illustrated, the LIDAR chip 606 includes eight FMCW LIDAR transceivers 501 arranged in a linear array. However, in other embodiments, the FMCW LIDAR transceivers 501 may have some other arrangement (e.g., two-dimensional, rectangular, etc.). Each SCPA (indicated in the drawing by a small double-sided arrow at the end of each dotted line) simultaneously and independently emits and receives light 608 with the assistance of a lens system 607 over a corresponding viewing angle or angular Field-of-View (FoV). Each SCPA covers a particular angular FoV to provide a particular pixel rate for the FMCW LIDAR system including the LIDAR chip 606. Z parallel FMCW LIDAR transceivers 501 can cover a Z times larger angular FoV and provide a Z times faster pixel rate, where Z is an integer. For a high performance FMCW LIDAR system, a wide FoV and fast pixel rate can be important.

[0036] 7a-7c show examples of mechanically assisted laser beam scanning in a SCPA-based FMCW LIDAR system according to one or more embodiments. In FIG. 7a, both the photon chip 606 and the lens system 607 are mounted on a rotating platform 701. The photon chip 606 can be an embodiment of the LIDAR chip 606, the LIDAR transceiver 501, or some combination thereof. In the illustrated embodiment, the photon chip 606 can achieve solid-state scanning in a first dimension (e.g., vertical) and the rotating platform 701 can achieve 360 ​​degrees in an orthogonal second dimension (e.g., horizontal). In FIG. 7b, the photon chip 606 and the lens system 607 are fixed and the laser beam is directed by a moving mirror 702 (e.g., a Galvo Mirror). In FIG. 7c, the photon chip 606 and the lens system 607 are fixed and the laser beam is directed by a rotating Polygon mirror 703. The movable mirror 702 and / or the polygon mirror 703 may generally be referred to as a scanning mirror, and the scanning mirror (as described below in connection with FIG. 12) may be configured to scan the beam (the transmitted signal) in a second dimension within the field of view of the scanner module, the second dimension being orthogonal to one angular dimension.

[0037] The photonic chip 606 can achieve all-solid-state beam steering, and in some cases may be two-dimensional (e.g., optical antennas arranged in a two-dimensional array), but the overall field of view and addressable positions of the FMCW LIDAR can be greatly improved with the assistance of mechanical devices, as described in the examples above.

[0038] FIG. 8 shows a diagram of a first embodiment of a coherent pixel 813 that uses two polarizations of light to improve the performance of FMCW LIDAR systems according to one or more embodiments. Input light 801 originating from a laser is incident on the coherent pixel and split by an X / (1-X) splitter 802, also called splitter 802. X% of the light exits the top port of the splitter to constitute the TX signal, and (1-X)% of the light exits the bottom port of the splitter to constitute the local oscillator (LO) signal. Depending on the system parameters, an optimal splitting ratio can be selected. The TX signal is received by a polarization assembly 820. In the illustrated embodiment, the polarization assembly 820 includes a polarization splitter 803 and a polarization-insensitive free-space coupler 804. However, in other embodiments, for example as discussed below in connection with FIG. 9, the polarization splitter 803 and the polarization insensitive free space coupler 804 are replaced by a single polarization-splitting vertical chip-free space coupler. The polarization splitter 803 is also called a polarizer, which separates transverse electric (TE) and transverse magnetic (TM) polarizations. As an example, the input light in FIG. 1 may be TE-polarized. TM-polarized light can be used without changing this concept. Since the TX signal light is TE-polarized light, the light is coupled into the top port on the right side of the polarization splitter 803. The TM-polarized light is output through the bottom port on the right side of the polarization splitter 803. The TX signal output from the polarization splitter 803 is input to the polarization insensitive free space coupler 804, which generates a free space light beam 805 with a linear polarization that matches the TE field of the preceding optical circuit 813. The polarization insensitive free space coupler 804 is an example of an optical antenna. For example, the polarization insensitive free space coupler can be a vertical grating, an edge coupler (e.g., an inverse tapered waveguide), or a tilted reflector. The free space beam 805 propagates through a quarter wave plate 806, which converts the linear polarization to circular polarization 807. The circular polarization 807 propagates for a predetermined distance, which delays the light compared to the LO signal. This beam reflects off a target surface 808, producing a reflected light beam 809.Depending on the surface characteristics, these reflected beams may maintain circular polarization or randomize polarization. The reflected light beam 809 propagates back through free space and secondarily through the quarter wave plate 806. If the reflected beam 809 maintained circular polarization, the transmitted beam 810 (with respect to the originating transmit and receive optical circuit 813) will have TM polarization. If the reflected beam 809 has randomized polarization, the transmitted beam 810 will have random polarization. The transmitted beam 810 is again coupled into the coherent pixel 813 and propagates again into the top right port of the polarization splitter 803. If the received light beam is TM polarized, all of the light is coupled into the bottom left port of the polarization splitter 803. If the received beam is randomly polarized, half of the nominal optical power is coupled into the bottom left port. Light coupled into the lower left port of 803 is injected into a two-input power optical mixer 811 which mixes the delayed receive signal with the LO signal. The optical mixer produces one or more electrical signals 812 that are interpreted by the FMCW system. Removal of the quarter wave plate only affects the system performance for polarization-preserving target surfaces and does not affect the fundamental principles of the concept.

[0039] The polarization assembly 820 may be configured, for example, to combine an optical signal from a first waveguide (e.g., 802) to form a transmitted signal, polarize the transmitted signal to have a first polarization, polarize a reflected signal (coupled in via 804) based on a second polarization orthogonal to the first polarization to form a return signal, and couple the return signal (e.g., to 811) into a second waveguide for optical detection.

[0040] The coherent pixel 813 may be, for example, the coherent pixel 105. The coherent pixel 813 may also be an embodiment of the coherent pixel described above with reference to FIG. 2a. Similarly, the coherent pixel 813 may also be an embodiment of the coherent pixel described above with reference to FIG. 2b. For example, the bidirectional optical 2×2 splitter 202 is replaced with an X / (1-X) splitter 802 and a polarization splitter 803, and the optical antenna 200 is replaced with a polarization-insensitive free-space coupler 804. Also, for example, in the context of a LIDAR transceiver, for each X / (1-X) splitter, a polarization splitter is coupled along the optical path between the splitter and the optical antenna. The polarization splitter is also configured to polarize the transmitted signal to have a first polarization (e.g., TE) and polarize the reflected signal to form a return signal having a second polarization (e.g., TM) orthogonal to the first polarization.

[0041] 9 shows a diagram of a second embodiment of a coherent pixel 912 using two polarizations to improve the performance of an FMCW LIDAR system according to one or more embodiments. The second embodiment is substantially similar to the first embodiment, except that the polarization splitter 803 and free-space coupler 804 in the polarization assembly 820 of FIG. 8 are replaced with a single polarization-splitting vertical chip-free-space coupler 903 as shown in FIG. 9. The free-space coupler receives TE light from the left input and produces a free-space beam 904 with TE polarization. Meanwhile, the TM light incident on the coupler is coupled into the bottom port of an optical device connected to an optical mixer 910. The function and / or structure of the remainder of the system according to this second embodiment designated 901, 902, 904, 905, 906, 907, 908, 909, 910, and 911 is substantially the same as 801, 802, 805, 806, 807, 808, 809, 810, 811, and 812.

[0042] 9, it should be noted that the functions of the polarization assembly 820 and the polarization-splitting vertical chip-to-free space coupler 903 are the same. The polarization assembly 820 is configured, for example, to combine an optical signal from a first waveguide (e.g., 902) to form a transmitted signal, polarize the transmitted signal to have a first polarization, polarize a reflected signal (incoupled via 903) based on a second polarization orthogonal to the first polarization to form a return signal, and couple the return signal (e.g., to 910) into a second waveguide for optical detection.

[0043] The coherent pixel 912 may be, for example, the coherent pixel 105. The coherent pixel 912 may be an embodiment of the coherent pixel also described above with reference to Fig. 2c. Similarly, the coherent pixel 912 may be an embodiment of the coherent pixel also described above with reference to Fig. 2d. For example, the optical splitter 212 is replaced with an X / (1-X) splitter 902 and the polarization splitting antenna 210 is replaced with a single polarization-splitting vertical chip-to-free space coupler 903.

[0044] FIG. 10 illustrates a method of using coherent pixels in a focal plane array (FPA) for FMCW applications according to one or more embodiments. The coherent pixels in FIG. 10 can be, for example, coherent pixel 813 and / or coherent pixel 912. The FPA uses the coherent pixels to form a beam steering device. In FIG. 10, light entering M input waveguides 1001 is split among N output waveguides 1003 by M×N splitter 1002, where M and N are integers. The N output waveguides are connected to an array of coherent pixels 1004. This array can be one-dimensional or two-dimensional, depending on whether one-dimensional or two-dimensional beam steering is required. Each coherent pixel 1005 emits TE-polarized light 1006 that propagates through a quarter wave plate 1007 that converts the light into circularly polarized light 1008. The circularly polarized light passes through a lens 1009, which is comprised of one or more lens elements. The lens converts the spatially distributed circularly polarized beam of light into a tilted circularly polarized light beam 1010. The output angle of the lens (e.g., determined in part by the position of the coherent pixel 1005 that emitted the beam) depends on the position of the input beam and the lens 1009 to allow for a beam steering action. The tilted beam reflects off the target 1011. The diffusely reflected light returns to the lens at the same angle 1012. This reflected light may maintain its circular polarization or may be randomly polarized, depending on the characteristics of the target. The reflected light beam passes back through the lens 1009, which maps the angle of the beam to a specific location on the FPA. The transmitted beam 1013 passes back through the quarter wave plate 1007. If the reflected light maintains its circular polarization, the transmitted light 1014 is TM-polarized. If the reflected light is randomly polarized, the transmitted light 1014 has a random polarization. Passing transmitted light 1014 is recombined into an array of coherent pixels 1004 which convert the light into an electrical signal as previously described.

[0045] 11a-11d illustrate electrical wiring schemes for an SCPA according to one or more embodiments. The electrical wiring schemes can significantly reduce the number of electrical I / Os for the photonic chip of the LIDAR transceiver. Scheme 1 is illustrated in FIG. 11a and FIG. 11b. Scheme 2 is illustrated in FIG. 11c and FIG. 11d. In this example, a 1-8 3-stage binary tree switch network is illustrated, with one electrical control signal for each switch and a coherent pixel array, with each coherent pixel having two electrical outputs (e.g., I / Q signals). In Scheme 1, switches in the same stage are electrically connected together. With only three switch control signals, the LIDAR system can switch between any of the eight coherent pixels. All I output signals output from the coherent pixels are connected together as one shared output (RX_I), and all Q output signals are connected together as another shared output (RX_Q). If only one coherent pixel is activated by the switch network, the remaining coherent pixels receive very little light as its transmitter signal or its LO signal. Thus, the shared output shows the exact signal from the activated pixel with very little crosstalk from adjacent pixels. In this example, scheme 1 reduces the number of I / O signals to a minimum of five for a total of seven switch inputs and 16 coherent pixel outputs. The reduction in electrical I / O becomes even more significant as the scale of the SCPA increases and / or the number of parallel SCPAs increases. In scheme 2, two or more coherent pixels can be selected for simultaneous transmission and reception of light. In FIG. 11c, the switch control signal and the coherent pixel output signal are split between the top and bottom halves of the 1-8 binary switch network to generate five switch control and four receiver outputs. In operation, the first switch is controlled to have a 50 / 50 split ratio at the two outputs to deliver uniform optical power to the top and bottom halves of the 1-8 switch tree.Through independent control and readout capability for the top and bottom halves of the tree, one pixel from the top half and one pixel from the bottom half can be activated simultaneously. Scheme 2 can be applied to Scheme 1 by operating the first switch stage in the normal binary mode, but also allows arbitrary control of the split percentage of the first switch stage, providing a more flexible and potentially software-defined beam scanning option at the cost of some hardware.

[0046] 12 illustrates a system diagram of an SCPA-based FMCW LIDAR system in accordance with one or more embodiments. Scanner module 1201 includes an SCPA LIDAR chip 1205 having single or multiple FMCW transceiver channels and a lens system 1203 including one or more optical elements. In some embodiments, lens system 1203 is an embodiment of lens system 507.

[0047] The SCPA LIDAR chip 1205 includes one or more frequency modulated continuous wave (FMCW) LIDAR transceivers implemented as one or more integrated optical circuits that may include an input port, optical antennas, an optical switch, splitters, and mixers. The input port is configured to receive a frequency modulated laser signal. The optical switch is configured to switchably couple the input port to the optical antenna and form an optical path between the input port and the optical antenna. For each optical path from the input port to one of the optical antennas, a splitter is coupled along the optical path. The splitter is configured to split a received portion of the laser signal into a local oscillator signal and a transmitted signal - where the transmitted signal is emitted via the optical antenna and a reflection of the transmitted signal is received via the optical antenna as a reflected signal - and to output a return signal that is a portion of the reflected signal. For each splitter, a mixer is coupled to receive the return signal and the local oscillator signal from the splitter, and the mixer is configured to mix the return signal and the local oscillator signal to generate one or more output signals used to determine depth information about a field of view of the LIDAR system (also referred to as a field of view of the scanner module 1201).

[0048] In some embodiments, the lens system 1203 generates collimated transmitted signals that scan the field of view of the scanner module 1201 along one or more angular dimensions (e.g., azimuth or elevation). The scanner module 1201 has a field of view of 5 degrees or more along one angular dimension. Also, in embodiments having a two-dimensional array of optical antennas (e.g., a rectangular grid), signals from multiple optical antennas can be scanned in two dimensions within the field of view of the scanner module 1201. For example, scanning is performed in the first and second dimensions, but the field of view of the scanner module 1201 is 5 degrees or more along the first dimension and 5 degrees or more along the second dimension. The two-dimensional scanning in the above example is performed by simply selectively using different coherent pixels from each other.

[0049] The scanner module 1201 may also include a scanner 1202 to assist in laser beam scanning and / or a quarter wave plate (QWP) 1204 to improve polarization dependent sensitivity. The scanning mirror 1202 may be, for example, a scanning mirror as described above in connection with Figures 7b and 7c. In an embodiment using a scanning mirror 1202, the field of view of the scanner module 1201 is 5 degrees or more along a first dimension (scanned by selective use of coherent pixels) and 10 degrees or more along a second dimension (scanned at least in part by movement of the scanning mirror 1202). The light source for the LIDAR chip 1205 may be directly integrated into the same chip or coupled via a fiber optic component. As shown, the light source is an FMCW laser source 1207 that generates a frequency modulated optical signal for FMCW LIDAR operation. The laser source 1207 may be further boosted by an optical amplifier 1206 to increase the range of the FMCW LIDAR. The optical amplifiers can be semiconductor optical amplifier (SOA) chips or erbium-doped optical fiber amplifiers (EDFA). The FMCW laser source 1207 is controlled by a laser driver circuit 1208, which is typically a controllable low-noise current source. The output of the coherent pixels is transferred to an array of transimpedance amplifier (TIA) circuits 1211. The on-chip switches are controlled by a switch driver array 1210. The FMCW processing engine can be implemented with one or more FPGA, ASIC, or DSP chips, including the functions of SCPA control and correction logic 1215, FMCW LIDAR frame management and point cloud processing 1214, multi-channel analog-to-digital converter 1216, FMCW LIDAR DSP 1212, and FMCW laser chirp control and correction logic 1213. If the SCPA LIDAR chip 1205 is implemented as a CMOS silicon photonic platform, some or all of the electrical circuit functions can be implemented monolithically with the photonic circuits on a single chip. The data output 1220 of the FMCW processing engine is depth information.Depth information can include, for example, the three-dimensional position data of a typical LIDAR point cloud as well as other information such as speed, reflectivity, etc. that FMCW LIDAR can measure.

[0050] As previously mentioned, a high performance FMCW LIDAR system can be dependent on a wide FoV and fast pixel rate. It should be noted that the scanner module 1201 can aim at least 100K points per second across the FoV of the scanning module 1201.

[0051] FIG. 12 illustrates an exemplary LIDAR system. In alternative configurations, different and / or additional components may be included in the LIDAR system. Additionally, the functionality described in connection with one or more components shown in FIG. 12 may be distributed among the components in a manner other than that described in connection with FIG. 12. For example, in some embodiments, the SCPA LIDAR chip 1205 may be separate from the scanner module 1201. Additional configuration information

[0052] It should be noted that the drawings and the foregoing description relate to preferred embodiments by way of example only, and from the foregoing discussion, alternative embodiments of the structures and methods disclosed herein are readily discernible as viable alternatives which may be employed without departing from the principles of what is claimed.

[0053] Although the specific description includes many details, these should not be interpreted as limiting the scope of the present invention, but merely as illustrating different examples. It should be understood that the scope of the present disclosure includes other embodiments not discussed in the above details. Various other modifications, changes, and alterations that become apparent to those skilled in the art can be made in the arrangement, operation, and details of the methods and apparatus disclosed herein without departing from the spirit and scope defined in the appended claims. Therefore, the scope of the present invention should be determined by the appended claims and their legal equivalents.

[0054] Alternative embodiments are implemented in computer hardware, firmware, software, and / or combinations thereof. An example implementation may be implemented as a computer program product tangibly embodied in a machine-readable storage device for execution by a programmable processor, and the steps of the method may be performed by the programmable processor executing a program of instructions to perform functions by operating on input data and generating output. The embodiments may be advantageously implemented in one or more computer programs executable in a programmable system including at least one programmable processor coupled to receive and transmit data and instructions for a data storage system, at least one input device, and at least one output device. Each computer program may be implemented in a high-level procedural or object-oriented programming language, or assembly or machine language as appropriate, and in some cases the language may be a compiled or parsed language. Suitable processors include, by way of example, general-purpose and special-purpose microprocessors. Typically, the processor receives instructions and data from a read-only memory and / or a random access memory. Typically, a computer includes one or more mass storage devices for storing data files, and these devices include magnetic disks, such as internal hard disks and removable disks, magneto-optical disks, and optical disks. Suitable storage devices for tangibly implementing computer program instructions and data include, by way of example, all forms of non-volatile memory, including semiconductor memory devices such as EPROM, EEPROM, and flash memory devices, magnetic disks such as internal hard disks and removable disks, magneto-optical disks, and CD-ROM disks. All of the foregoing may be supplemented by, or incorporated in, application specific integrated circuits (ASICs) and other forms of hardware. [Item of invention] [Item 1] 1. A Frequency Modulated Continuous Wave (FMCW) LIDAR transceiver implemented on a Photonic Integrated Circuit, the Photonic Integrated Circuit comprising: an input port configured to receive a frequency modulated laser signal; A plurality of optical antennas; an optical switch configured to switchably couple the input port to the optical antenna to form an optical path between the input port and the optical antenna; a splitter coupled along each optical path from the input port to one of the optical antennas; the splitter splitting a received portion of the laser signal into a local oscillator signal and a transmitted signal, the transmitted signal being emitted via the optical antenna and a reflection of the transmitted signal being received as a reflected signal via the optical antenna; configured to output a return signal that is a portion of the reflected signal; and for each splitter, a mixer coupled to receive the return signal and the local oscillator signal from the splitter, the mixer configured to mix the return signal and the local oscillator signal to generate one or more output signals used to determine depth information about a field of view of the transceiver. [Item 2] and for each splitter, a polarization assembly coupled along the optical path between the splitter and the optical antenna, the polarization assembly comprising: combining optical signals from the first waveguide to form the transmitted signal; polarizing the transmitted signal to have a first polarization; polarizing the reflected signal according to a second polarization orthogonal to the first polarization to form a return signal; Item 2. The FMCW LIDAR transceiver of item 1, configured to couple the return signal to a second waveguide for optical detection. [Item 3] 2. The FMCW LIDAR transceiver of claim 1, wherein the FMCW LIDAR transceiver includes an individual splitter for each of the plurality of antennas, each splitter being coupled along the optical path between the optical switch and a corresponding antenna. [Item 4] 2. The FMCW LIDAR transceiver of claim 1, wherein the FMCW LIDAR transceiver includes only one splitter coupled between the input port and the optical switch. [Item 5] 2. The FMCW LIDAR transceiver of claim 1, wherein the array of the multiple antennas is selected from the group including a standard array, a linear array, and a rectangular array. [Item 6] 2. The FMCW LIDAR transceiver of claim 1, wherein the one or more output signals include a quadrature output signal and an in-phase output signal for each return signal. [Item 7] The optical switch comprises: 2. The FMCW LIDAR transceiver of item 1, comprising a passive optical splitter that splits the frequency modulated laser signal between at least two optical paths. [Item 8] The optical switch comprises: 2. The FMCW LIDAR transceiver of item 1, including an active optical splitter that switchably couples the frequency modulated laser signal to only one of at least two optical paths. [Item 9] 9. The FMCW LIDAR transceiver of claim 8, wherein the optical switch includes a plurality of active optical splitters. [Item 10] 2. The FMCW LIDAR transceiver of claim 1, wherein the optical switch optically couples the frequency modulated laser signals to respective optical antennas one at a time during a scanning period of the FMCW transceiver. [Item 11] 1. A frequency modulated continuous wave (FMCW) LIDAR system, comprising: a LIDAR chip including a FMCW LIDAR transceiver implemented on a photonic integrated circuit; a lens; The optical integrated circuit comprises: an input port configured to receive a frequency modulated laser signal; A plurality of optical antennas; an optical switch configured to switchably couple the input port to the optical antenna to form an optical path between the input port and the optical antenna; a splitter coupled along each optical path from the input port to one of the optical antennas; the splitter splitting a received portion of the laser signal into a local oscillator signal and a transmitted signal, the transmitted signal being emitted via the optical antenna and a reflection of the transmitted signal being received as a reflected signal via the optical antenna; configured to output a return signal that is a portion of the reflected signal; for each splitter, a mixer coupled to receive the return signal and the local oscillator signal from the splitter, the mixer configured to mix the return signal and the local oscillator signal to generate one or more output signals used to determine depth information about a field of view of an FMCW LIDAR; the lens is positioned to collimate the transmitted signals emitted via the plurality of antennas; The lens is also positioned to receive the reflected signal and couple the reflected signal to the emitting optical antenna of the FMCW LIDAR system. [Item 12] For each splitter, a polarization assembly coupled along the optical path between the splitter and the optical antenna, the polarization assembly comprising: combining optical signals from the first waveguide to form the transmitted signal; polarizing the transmitted signal to have a first polarization; polarizing the reflected signal according to a second polarization orthogonal to the first polarization to form a return signal; Item 12. The FMCW LIDAR system of item 11, configured to couple the return signal to a second waveguide for optical detection. [Item 13] Item 13. The FMCW LIDAR system of item 12, further comprising a quarter-wave plate located along the optical path of the emitted transmitted signal and configured to convert the reflected signal from a circular polarization to a second linear polarization orthogonal to the first linear polarization so as to convert the transmitted signal from a first linear polarization to a circular polarization. [Item 14] The lens is projecting a transmitted signal emitted from a first antenna of the plurality of antennas onto a corresponding portion of a field of view of the FMCW LIDAR system; Item 12. The FMCW LIDAR system of item 11, configured to provide a reflection of the transmitted signal to the first antenna. [Item 15] 12. The FMCW LIDAR system of claim 11, wherein the plurality of optical antennas are arranged in a linear array and the lens generates a collimated transmitted signal that scans a field of view of the transceiver along one angular dimension. [Item 16] 16. The FMCW LIDAR system of claim 15, wherein the FMCW LIDAR system has a field of view of 5 degrees or greater along one angular dimension. [Item 17] 16. The FMCW LIDAR system of item 15, further comprising a scanning mirror configured to scan the transmitted signal in a second dimension within a field of view of the FMCW LIDAR system, the second dimension being orthogonal to the one angular dimension. [Item 18] 12. The FMCW LIDAR system of claim 11, wherein the FMCW is configured to emit the multiple transmitted signals from the multiple antennas such that the multiple transmitted signals scan a portion of a field of view of the FMCW LIDAR system in two dimensions. [Item 19] 20. The FMCW LIDAR system of claim 18, wherein the two dimensions are a first dimension and a second dimension, and the field of view of the scanning module is greater than or equal to 5 degrees along the first dimension and greater than or equal to 5 degrees along the second dimension. [Item 20] Item 12. The FMCW LIDAR system of item 11, wherein the FMCW LIDAR system is configured to aim at least 100K points per second across a field of view of the FMCW LIDAR system.

Claims

1. 1. A LIDAR transceiver comprising: The LIDAR transceiver includes: a light source input configured to receive a laser signal; A plurality of coherent cells; an optical switch configured to switchably couple the light source input to the plurality of coherent cells; Equipped with One or more of the coherent cells of the plurality of coherent cells include an input port coupled to the optical switch; An optical antenna; a splitter coupled between the input port and the optical antenna; Equipped with The splitter comprises: splitting a received portion of the laser signal into a local oscillator signal and a transmit signal, the transmit signal being emitted via the optical antenna and a reflection of the transmit signal being received as a reflected signal via the optical antenna; A return signal that is a part of the reflected signal is output. The LIDAR transceiver is configured as follows:

2. The one or more coherent cells include a mixer coupled to receive the return signal and the local oscillator signal from the splitter, the mixer configured to mix the return signal and the local oscillator signal to generate one or more output signals; 10. The LIDAR transceiver of claim 1 further comprising:

3. 3. The LIDAR transceiver of claim 2, further comprising one or more processors configured to determine depth information about a field of view of the LIDAR transceiver based on the one or more output signals.

4. 3. The LIDAR transceiver of claim 2, wherein the one or more output signals include a quadrature output signal and an in-phase output signal with respect to the return signal.

5. 3. The LIDAR transceiver of claim 2, wherein the one or more coherent cells further comprise one or more photodiodes coupled to the mixer to provide the one or more output signals as electrical signals.

6. 2. The LIDAR transceiver of claim 1, wherein a plurality of optical paths are defined between the light source input of the LIDAR transceiver and the plurality of coherent cells, respectively.

7. the one or more coherent cells further comprising a polarizing assembly disposed between the splitter and the optical antenna; The polarizing assembly comprises: combining optical signals from a first waveguide to form the transmit signal; polarizing the transmit signal to have a first polarization; polarizing the reflected signal according to a second polarization to form the return signal; Coupling the return signal into a second waveguide for optical detection.

2. The LIDAR transceiver of claim 1 , configured as follows:

8. 8. The LIDAR transceiver of claim 7, wherein the first polarization is orthogonal to the second polarization.

9. 10. The LIDAR transceiver of claim 1, wherein the plurality of coherent cells are arranged in a linear array or a two-dimensional array.

10. 10. The LIDAR transceiver of claim 1, wherein the optical switch includes a passive optical splitter that splits the laser signal into at least two optical paths.

11. 10. The LIDAR transceiver of claim 1, wherein the optical switch includes an active optical splitter that switchably couples the laser signal to only one of at least two optical paths.

12. 2. The LIDAR transceiver of claim 1, wherein the optical switch optically couples the laser signal to the plurality of coherent cells, one coherent cell at a time during a scanning period of the LIDAR transceiver.

13. 10. The LIDAR transceiver of claim 1, wherein the laser signal comprises a frequency modulated continuous wave (FMCW) laser signal.

14. 1. An automotive LIDAR system comprising: one or more LIDAR transceivers; and a lens coupled to the LIDAR transceivers, The LIDAR transceiver includes: a light source input configured to receive a laser signal; A plurality of coherent cells; an optical switch configured to switchably couple the light source input to the plurality of coherent cells; Equipped with One or more of the coherent cells of the plurality of coherent cells include an input port coupled to the optical switch; An optical antenna; a splitter coupled between the input port and the optical antenna; Equipped with The splitter comprises: splitting a received portion of the laser signal into a local oscillator signal and a transmit signal, the transmit signal being emitted via the optical antenna and a reflection of the transmit signal being received as a reflected signal via the optical antenna; A return signal that is a part of the reflected signal is output. It is configured as follows: The lens is Collimating the transmit signal emitted by the optical antenna; The reflected signal is received and coupled to the optical antenna. The LIDAR system for an automobile is configured as follows.

15. The one or more coherent cells include a mixer coupled to receive the return signal and the local oscillator signal from the splitter, the mixer configured to mix the return signal and the local oscillator signal to generate one or more electrical output signals; 15. The automotive LIDAR system of claim 14, further comprising:

16. 16. The automotive LIDAR system of claim 15, further comprising one or more processors coupled to the LIDAR transceiver and configured to determine depth information about a field of view of the LIDAR transceiver based on the one or more electrical output signals.

17. 16. The automotive LIDAR system of claim 15, wherein the one or more electrical output signals include a quadrature output signal and an in-phase output signal.

18. A LIDAR chip comprising a plurality of LIDAR transceivers, One or more LIDAR transceivers of the plurality of LIDAR transceivers include: a light source input configured to receive a laser signal; one or more coherent cells; an optical switch configured to switchably couple the light source input to the one or more coherent cells; Equipped with The one or more coherent cells include an input port coupled to the optical switch; An optical antenna; a splitter coupled between the input port and the optical antenna; Equipped with The splitter comprises: splitting a received portion of the laser signal into a local oscillator signal and a transmit signal, the transmit signal being emitted via the optical antenna and a reflection of the transmit signal being received as a reflected signal via the optical antenna; A return signal that is a part of the reflected signal is output. The LIDAR chip is configured as follows.

19. The one or more coherent cells include a mixer coupled to receive the return signal and the local oscillator signal from the splitter, the mixer configured to mix the return signal and the local oscillator signal to generate one or more electrical output signals; 20. The LIDAR chip of claim 18, further comprising:

20. 20. The LIDAR chip of claim 19, wherein the one or more electrical output signals include a quadrature output signal and an in-phase output signal.

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