Scanning lidar with optical switching

Abstract

A scanning lidar with no moving parts includes: a laser emitter having a first magneto-optical switch that transmits pulses to a first linear fiber array to a field of view (FOV); a receiver having optics that guides reflected light to a second orthogonal linear fiber array coupled to a second magneto-optical switch to transmit light to a detector; and a controller for processing detector signals and generating FOV data. A scanning method for improving resolution includes: scanning along a first direction; guiding light reflected from an object along a second direction orthogonal to the first direction to form a received beam provided to a detector; processing detector signals to generate a pixel array; and altering the intensity distribution within a pixel by synchronously changing the polarization of the emitted and received light using an associated Faraday rotator and a phase mask to continuously shift peak intensity within the pixel.

Description

[0001] Cross-reference to related applications

[0002] This application claims the benefit of U.S. Provisional Application No. 62 / 850,573, filed May 21, 2019, the disclosure of which is incorporated herein by reference. Technical Field

[0003] This disclosure relates to scanning lidar and methods for improving the resolution of scanning lidar systems. Background Technology

[0004] LiDAR is an active remote sensing technology that uses light reflected from an emitter by an object within its field of view (FOV) to determine the range or distance to that object. This information can be processed to generate images or otherwise used for mapping, object recognition, object avoidance, navigation, and more in various types of vehicles (e.g., motor vehicles or drones). While many LiDAR solutions have been proposed and may be acceptable for specific applications, various strategies have associated drawbacks that may render them unsuitable for other applications. For example, various LiDAR systems have limited power and associated limited detection range to maintain eye safety, mechanically scan the FOV using moving parts, have limited frame rates, and are limited in adverse environmental conditions such as fog, mist, rain, snow, etc. Summary of the Invention

[0005] Real-time scanning lidar systems and methods include various embodiments incorporating all-optical switching, thus eliminating the need for moving parts. These embodiments facilitate scanning a large field of view (FOV) in three-dimensional space to provide multidimensional real-time data on objects within the FOV, such as location, extent, polarization, velocity, etc.

[0006] In one or more embodiments, a scanning lidar system includes: a transmitter having a laser and a first optical switch configured to receive laser pulses from the laser; a first plurality of optical fibers, each coupled to a different output of a plurality of outputs of the first optical switch; a first at least one optical element configured to receive the laser pulses from at least one of the first plurality of optical fibers and redirect the laser pulses to illuminate at least a portion of a field of view; a receiver including a second optical switch and at least one detector; a second plurality of optical fibers, each coupled to a different input of the second optical switch, the output of the second optical switch coupled to the at least one detector; a second at least one optical element configured to receive laser pulses reflected from the field of view and redirect the received reflected pulses to at least one of the second plurality of optical fibers; and at least one controller configured to control the first optical switch to sequentially direct the laser pulses from the input of the first optical switch to each of the plurality of outputs, control the second optical switch to sequentially direct light from each of the plurality of second optical fibers to the output of the second optical switch, and process signals from the at least one detector to generate data representing the field of view. The first and second optical switches may be all-optical switches, lacking moving parts respectively associated with switching light from an input to one of a plurality of outputs or from a plurality of outputs to an input. The first and second optical switches may include Faraday rotators. In at least one embodiment, the first and second optical switches comprise magneto-optical switches.

[0007] In various embodiments, the system may include a first microprocessor-based controller configured to control a first optical switch and a second microprocessor-based controller communicating with the first controller and configured to control a second optical switch.

[0008] In one or more embodiments, the laser includes a fiber laser or any pulsed laser source connected to an optical fiber, the fiber laser or any pulsed laser source connected to the optical fiber being configured to generate pulses having SWIR wavelengths between 900 nanometers (nm) and 1700 nanometers (nm). In at least one embodiment, the laser is configured to generate pulses having a nominal wavelength of 1550 nanometers (nm).

[0009] In one or more embodiments, the at least one first optical element includes an aspherical lens configured to form an output beam having an elliptical cross-section. The optical element may be shaped to form an output beam that diverges at an angle along a first axis by at least 20 times the angle along a second axis perpendicular to the first axis. In at least one embodiment, the output beam diverges at an angle of 40 degrees in the horizontal direction and at an angle of 1 degree in the vertical direction.

[0010] In one or more embodiments, the system includes a plurality of optical elements, each associated with one of a plurality of optical fibers to provide an output beam illuminating the FOV.

[0011] In one or more embodiments, the at least one second optical element includes a collecting optics located upstream of a beam-forming optics configured to form a beam with an elliptical cross-section. The beam-forming optics can provide a beam with an elliptical cross-section that diverges at an angle along a second axis at least 20 times greater than it diverges at an angle along a first axis perpendicular to the second axis. In one embodiment, the receiver includes both the collecting optics and the beam-forming optics to provide a received beam with a horizontal divergence of 1 degree and a vertical divergence of 20 degrees.

[0012] In one or more embodiments, a first plurality of optical fibers are arranged in a first linear array, and the inputs of a second plurality of optical fibers are located in a second linear array orthogonal to the first linear array.

[0013] In various embodiments, at least one detector includes an avalanche photodiode. In at least one embodiment, the at least one detector includes a plurality of detectors configured to operate in parallel.

[0014] In one or more embodiments, the laser is configured to emit polarized pulses, and the detector includes a plurality of detectors, each configured to detect received light with different polarization angles. The at least one controller may be configured to process signals from the plurality of detectors to generate polarization degree or polarization angle data representing the field of view. In at least one embodiment, the first at least one optical element and the second at least one optical element each include a polarization rotator and a polarization phase mask controlled by the at least one controller. In at least one embodiment, the first at least one optical element and the second at least one optical element each include a first linear polarizer, a Faraday rotator, a half-wave delay phase mask, and a second linear polarizer. The at least one controller may be configured to operate the laser, as well as the first and second optical switches, to refresh data at 100 Hz to provide 100 frames per second.

[0015] In various embodiments, a modular system is provided having a control unit coupled to an optical head via a fiber optic bundle. In one embodiment, the system includes a housing and at least one optical head. The housing contains a transmitter, a receiver, and at least one controller. The at least one optical head is located outside the housing and includes a first at least one optical element and a second at least one optical element, wherein a first plurality of optical fibers and a second plurality of optical fibers extend between the first housing and the optical head. The housing of the control unit may contain a transmitter and a receiver associated with each of a plurality of remotely positioned optical heads, each optical head coupled via an associated fiber optic bundle.

[0016] In at least one embodiment, the vehicle includes a lidar system as described herein, the lidar system having a controller unit connected to one or more head units. The vehicle may include a lidar system having a fixed controller unit optically coupled to a head unit mounted on an actuator configured to rotate the mounted head unit.

[0017] The embodiments may also include a method for lidar scanning, the method comprising: generating a laser pulse; optically switching the laser pulse to each of a first plurality of optical fibers arranged in a first linear array to illuminate a field of view; directing light reflected from an object illuminated by the laser pulse within the field of view to a second plurality of optical fibers arranged in a second linear array; optically switching the light from the second plurality of optical fibers to direct the light to at least one detector; and processing signals from the detector to generate data representing the field of view. Generating the laser pulse may include using a fiber laser with an output wavelength between 900 nm and 1700 nm. In one embodiment, the nominal output wavelength is 1550 nm to provide increased capabilities for remote sensing while meeting eye safety requirements.

[0018] In one or more embodiments, the method includes optically switching laser pulses and optically switching light from a second plurality of optical fibers by controlling an all-optical solid-state switch having a Faraday rotator but no moving parts, such all-optical solid-state switch being implemented, for example, by a magneto-optical switch.

[0019] In one or more embodiments, the method may include shaping laser pulses output from a first plurality of optical fibers to form a pulsed beam having an elliptical cross-section, the pulsed beam diverging angularly along a first axis at least 20 times more than angularly diverging along a second axis perpendicular to the first axis. In one embodiment, the angular divergence along the first axis is 40 degrees, while the angular divergence along the second axis is 1 degree.

[0020] Various embodiments may include scanning the FOV by sequentially guiding laser pulses to a first linear array of optical fibers, wherein the first linear array of optical fibers is orthogonally positioned relative to a second linear array of optical fibers that receive reflected light from objects within the FOV.

[0021] In at least one embodiment, the method includes optically switching light from a second plurality of optical fibers to a single optical fiber coupled to a detector. In some embodiments, a plurality of detectors are provided, and optically switching light from the second plurality of optical fibers includes optically switching light from different groups of optical fibers to different detectors operating in parallel.

[0022] In one or more embodiments, the method includes polarizing a laser pulse illuminating a field of view, detecting the polarization of light reflected from an object illuminated by the laser pulse, and generating polarization data representing the field of view based on the detected polarization of the light reflected from the object. The method may further include altering the polarization of the laser pulse to increase the light intensity detected from a selected fiber among a second plurality of optical fibers relative to the light intensity from an optical fiber adjacent to the selected fiber.

[0023] The embodiments also include a method for improving scanning resolution. The method includes: generating a continuous wave (CW) or pulsed laser beam; scanning the laser beam along a first direction to generate an emitted laser beam to illuminate a field of view; guiding light reflected from an object illuminated by the emitted laser beam within the field of view along a second direction orthogonal to the first direction to form a received beam provided to at least one detector; processing signals from the at least one detector to generate a two-dimensional pixel array; and altering the intensity distribution within selected pixels by synchronously changing the polarization of the emitted laser beam and the received beam provided to the at least one detector to move the detected peak intensity in a continuous manner within the selected pixels.

[0024] In one or more embodiments, the method includes: altering the intensity distribution of a detected received beam within a pixel by guiding a generated or emitted laser beam through a Faraday rotator and a phase mask; and controlling the Faraday rotator to change the polarization of the emitted laser beam. The method may further include guiding the received beam through a second Faraday rotator and a second phase mask, wherein the second Faraday rotator is controlled synchronously with a first Faraday rotator. In one embodiment, the phase mask comprises a half-wave delayer phase mask. In one embodiment, the phase mask comprises an eddy current delayer.

[0025] In various embodiments, the method includes: optically switching a laser beam to guide light to sequentially illuminate a plurality of transmitter optical fibers arranged in a first linear array; and guiding light reflected from an object to a plurality of receiver optical fibers arranged in a second linear array, the second linear array being orthogonally positioned relative to the first linear array.

[0026] The embodiment may also include a system comprising: a laser configured to generate a laser beam; a first Faraday rotator located upstream of a first half-wave delay phase mask, the first Faraday rotator and the first phase mask selectively altering the polarization of an output beam in response to a polarization control signal; a first magneto-optical switch configured to receive the output beam and selectively redirect the output beam to one of a plurality of outputs in response to an emission scan control signal to scan the output beam along a first direction to illuminate a field of view; at least one optical element configured to collect light reflected from the field of view along a second direction orthogonal to the first direction; and a second magneto-optical switch configured to selectively redirect light from each of a plurality of inputs to an output in response to receiving a scan control signal to scan light reflected from the field of view along the second direction. The system comprises: a first magneto-optical switch and a second magneto-optical switch; a second Faraday rotator positioned to receive the light output from the second magneto-optical switch and positioned upstream of a second half-wavelength delay phase mask, the second Faraday rotator and the second phase mask selectively changing the polarization of the received light in response to a polarization control signal; at least one detector positioned to receive the light from the second phase mask; and at least one controller configured to generate an emission scan signal and a reception scan signal to control the first magneto-optical switch and the second magneto-optical switch to process the signals from the at least one detector to generate a two-dimensional pixel array, and to change the intensity distribution within the selected pixel to shift the peak intensity within the selected pixel by generating a polarization control signal to synchronously control the first Faraday rotator and the second Faraday rotator to change the polarization of the emitted laser beam and the received light supplied to the at least one detector.

[0027] In at least one embodiment, a scanning lidar system includes: a central module including a laser and an optical splitter configured to split an output from the laser among a plurality of optical splitter outputs; a first plurality of connecting optical fibers, each connected optical fiber coupled to a different one of the plurality of optical splitter outputs; and a plurality of optical heads, each optical head coupled to the central module via one of the first plurality of connecting optical fibers. Each optical head includes: a first optical switch having an input coupled to an associated one of the first plurality of connecting optical fibers; a plurality of transmission optical fibers coupled to an associated output of the first optical switch and having outputs arranged in a linear array along a first direction; at least one transmitter optical element configured to receive a laser pulse from at least one of the plurality of transmission optical fibers and redirect the laser pulse to illuminate at least a portion of a field of view; a second optical switch; a plurality of receiver optical fibers, each receiver optical fiber coupled to a different input of the second optical switch, the output of the second optical switch coupled to at least one detector; and at least one receiver optical element configured to receive a laser pulse reflected from the field of view and redirect the received reflected pulse to at least one of the receiver optical fibers. The system also includes at least one controller configured to control a first optical switch and a second optical switch, and to process signals from at least one detector to generate data representing the field of view, wherein the at least one controller and the at least one detector are disposed within the central module or the optical head.

[0028] In one or more embodiments, a method includes: generating a laser pulse in a central module; and splitting the laser pulse in the central module to deliver the laser pulse to each of a plurality of remotely positioned optical heads. In each of the plurality of remotely positioned optical heads, the method includes: optically switching the laser pulse to each of a first plurality of optical fibers arranged in a first linear array to illuminate a field of view; directing light reflected from an object illuminated by the laser pulse within the field of view to a second plurality of optical fibers arranged in a second linear array; and optically switching light from the second plurality of optical fibers to direct the light to at least one detector. The method further includes processing signals from the detectors to generate data representing the field of view.

[0029] In at least one embodiment, the scanning lidar system includes: a central module comprising a pulsed laser, a first magneto-optical switch, and a plurality of optical splitters, the magneto-optical switch being configured to switch the laser output to one of the plurality of optical splitters, each of the plurality of optical splitters being configured to divide a pulse from the laser into multiple splitter outputs; and a plurality of connecting optical fibers coupled to each output of each of the plurality of optical splitters. Multiple optical heads are remotely positioned relative to the central module, and each optical head is coupled to the central module via a connecting fiber associated with each of the multiple splitter outputs. Each of the multiple optical heads includes: multiple transmission fibers coupled to each of the multiple fiber splitters and having outputs arranged in a linear array along a first direction; at least one transmitter optics configured to receive laser pulses from at least one of the multiple transmitter fibers and redirect the laser pulses to illuminate at least a portion of a field of view; a second magneto-optical switch; multiple receiver fibers, each coupled to a different input of the second magneto-optical switch, the output of the second magneto-optical switch being coupled to at least one detector; and at least one receiver optics configured to receive laser pulses reflected from the field of view and redirect the received reflected pulses to at least one of the receiver fibers. The system also includes at least one controller configured to control the first and second magneto-optical switches and process signals from the at least one detector to generate data representing the field of view, wherein the at least one controller and the at least one detector are disposed within the central module or the optical head.

[0030] In one or more embodiments, a method includes: generating a laser pulse in a central module; optically switching the laser pulse to each of a plurality of fiber optic splitters in the central module; and splitting the laser pulse through each fiber optic splitter to deliver each laser pulse to each of a plurality of optical heads remotely positioned relative to the central module. The method includes: in each of the plurality of optical heads, directing the laser pulse from the plurality of fiber optic splitters to each of a plurality of transmission fibers arranged in a first linear array to illuminate a field of view; directing light reflected from an object illuminated by the laser pulse within the field of view to a plurality of receiver fibers arranged in a second linear array, the second linear array being orthogonal to the first linear array; and optically switching the light from the receiver fibers to direct the light to at least one detector. The method further includes processing signals from the detectors to generate data representing the field of view.

[0031] One or more embodiments can provide advantages for a variety of applications. For example, various embodiments of this disclosure provide a scanning lidar that operates at eye-safe wavelengths, which scans the field of view and receives reflected light to create images or multidimensional data representing the field of view using an orthogonally oriented fiber array with magneto-optical switches without requiring any moving parts. One or more embodiments provide improved range, frame rate, reliability, scalability, and robust operation under adverse weather conditions, making them suitable for use, for example, in autonomous vehicles and drones. Attached Figure Description

[0032] Figure 1 This is a block diagram illustrating the operation of a representative embodiment of a system or method for scanning lidar.

[0033] Figure 2 and Figure 3 This is a diagram showing a cross-section of a beam from the fiber linear array used to guide a transmitted beam or a received reflected beam into an orthogonally positioned fiber linear array in a representative embodiment.

[0034] Figure 4 This illustrates multidimensional data generated from detector signals associated with overlapping points or pixels of light pulses that correspond to optical switching or scanning.

[0035] Figure 5 The modular configuration or architecture of a scanning lidar sensor with a controller or central unit and at least one optical head, as shown in a representative embodiment, is illustrated.

[0036] Figure 6 A modular configuration or architecture of a scanning lidar sensor with a central unit is shown in another representative embodiment, the central unit having an optical splitter coupled upstream of transmitter optical switches of multiple optical heads.

[0037] Figure 7 A modular configuration or architecture of a scanning lidar sensor with a central unit is shown in another representative embodiment, the central unit having an optical splitter coupled downstream of transmitter optical switches of multiple optical heads.

[0038] Figure 8 A representative embodiment of a vehicle with a scanning lidar sensor is shown, which has a rotating optical head and / or one or more fixed optical heads.

[0039] Figure 9 This is a block diagram illustrating a scanning lidar with optical switches and multiple detectors for detecting the polarization of reflected light according to various embodiments.

[0040] Figure 10Representative embodiments of a system or method for improving the resolution within pixels of a laser-scanned field of view (FOV) by manipulating or scanning the polarization of emitted and received light using a Faraday rotator and a phase mask are shown.

[0041] Figure 11 The diagram illustrates how, according to various embodiments, the intensity within a portion of a pixel of a laser-scanned field of view (FOV) can be increased by manipulating the polarization of the emitted and received light.

[0042] Figure 12 This is a flowchart illustrating the operation of a system or method for performing lidar scanning using light switching according to one or more embodiments.

[0043] Figure 13 This is a flowchart illustrating the operation of a system or method for increasing the resolution of a laser-scanned field of view (FOV) using polarization manipulation according to one or more embodiments. Detailed Implementation

[0044] Detailed embodiments of the invention are disclosed herein as needed; however, it should be understood that the disclosed embodiments are merely examples of the invention and may be embodied in various alternative forms. The drawings are not necessarily drawn to scale; some features may be enlarged or minimized to show details of specific components. Therefore, the specific structural and functional details disclosed herein should not be construed as limiting, but merely as teaching those skilled in the art to use the representative basis of the invention differently.

[0045] As used in this specification, images or related terms are not limited to visual representations, but more generally refer to data representations of the field of view (FOV). Different types of data, such as localization / position, distance / range, intensity, polarization, velocity, etc., can be collected for each measurement point or pixel within the FOV to provide a multidimensional data array that can be processed by the controller without generating a visual representation of the data. Similarly, references to pixels do not imply or require a visual representation or display of associated data or an area on a display screen, but more generally refer to discrete measurement points or observation points within the FOV, where potential discrete measurements for a particular pixel localization are called subpixels, which can be used to improve or enhance resolution within the pixel. For example, subpixels corresponding to measurements generated from different laser pulses or different characteristics / attributes of laser pulses for a specific (x, y) pixel localization provide additional data that can be used to detect or identify temporal or spatial domain variations within the pixel to enhance resolution.

[0046] In its most general sense, a vehicle is a mechanical device used to carry, transport, or deliver something or to propel itself.

[0047] An optical switch is an all-optical switch that holds a signal as light from input to output, unlike an electro-optical switch which converts an optical signal into an electrical signal and returns it to an optical signal to route the optical signal or pulse from one channel to another (i.e., from input to one of multiple outputs, or from one of multiple inputs to an output). All-optical switches can be controlled by electrical signals or electronic controllers to provide spatial domain switching of optical signals or pulses. An optical switch without moving parts refers to a device that does not have any moving mechanical parts to perform the switching operation; that is, it does not include movable mirrors such as those provided in MEMS-based photonic switches.

[0048] Optical elements refer to any element or component that acts on light, including discrete elements such as mirrors, lenses (including graduated or gradient refractive index lenses), prisms, gratings, etc., as well as integrated optical devices and holographic optical elements that can also act on incident light to redirect light and / or modify one or more properties of light.

[0049] Figure 1 This is a block diagram illustrating the operation of a representative embodiment of a system or method for scanning lidar. System 100 includes a transmitter 102 configured to illuminate a field of view (FOV) 104 having at least one object 106, wherein reflected light from the object 106 is detected by a receiver 108. The transmitter 102 includes a laser 110 and a first optical switch 112 configured to receive laser pulses from the laser 110. In various embodiments, the laser 110 is a fiber laser operating in pulsed mode in the SWIR range, with a nominal output wavelength between 900 nm and 1700 nm. In at least one embodiment, the laser 110 operates at a nominal output wavelength of 1550 nm in an eye-safe zone, allowing the transmitter 102 to operate at higher power to provide a longer range and improved imaging / sensing performance. The laser 110 can be operated to provide, for example, a data frame rate between 100 and 500 Hz, and a laser pulse rate, for example, between 100 and 500 kHz. Of course, the data frame rate and laser pulse repetition rate will vary depending on the specific application and implementation.

[0050] exist Figure 1In the representative embodiment shown, the first optical switch 112 is an electronically controlled all-optical 1xN switch to transmit optical pulses output from the fiber laser 110 from the input of switch 112 to one of N outputs, controlled by an associated controller (e.g., one or more controllers 120). In one embodiment, the optical switch 112 is implemented by a 1x32 magneto-optical switch, similar to commercially available switches supplied by Agiltron Corporation of MA Woburn, USA, or Primanex Corporation of Qingdao, Shandong, China. The magneto-optical switch includes a Faraday rotator for switching the optical pulses, such that the switch does not include a moving part for performing the switching operation.

[0051] Each output of switch 112 is coupled to an associated optical fiber positioned in a linear array along a first axis or direction. In one embodiment, the linear array of transmitter optical fibers 114 is vertically oriented. The outputs of optical fibers 114 are positioned at the focal plane of transmission optics 116, which may be implemented by at least one optical element configured to receive laser pulses from optical fibers 114 and redirect the laser pulses such that light 118 is guided to different angles to illuminate corresponding portions of the FOV 104 containing one or more objects 106. The at least one optical element may include a diverging lens or one or more asymmetric, aspherical, and / or cylindrical optical elements to determine the desired coverage portion of the FOV 104 (in...). Figure 2 (Best shown in the image) to provide an oval or elliptical output beam at a specific angle. At least one optical element may include one or more lenses, each lens being associated with a single optical fiber, a group of optical fibers 114, or all of the optical fibers 114.

[0052] Receiver 108 receives the central ray 130 and off-axis rays 132, 136 within the reflected light 138 from object 106 within FOV 104. Receiver optics 140 includes at least one optical element configured to collect and receive laser pulses reflected from FOV 104 and redirect the received reflected pulses to at least one of a second plurality of optical fibers 150. The optical fibers 150 are arranged in a linear array orthogonally oriented relative to a linear array of transmitter optical fibers 114. In one embodiment, the fibers 150 are horizontally oriented (in...). Figure 3 (Best illustrated in the diagram). Of course, the orientation of the linear fiber arrays of the transmitter and receiver can be reversed, with the transmitter fiber oriented horizontally and the receiver fiber oriented vertically. Depending on the specific application and implementation, other orthogonal orientations are also possible.

[0053] exist Figure 1In a representative embodiment, receiver optics 140 is configured to collect off-axis reflected light 132 and redirect it to an associated fiber 152, while collecting representative central light 130 and redirecting it to fiber 154, and collecting representative off-axis light 136 and redirecting it to fiber 156 within fiber array 150. Receiver optics 140 includes at least one optical element, which may include a collecting optics located upstream of a beam-forming optics configured to form a beam with an elliptical cross-section. At least one optical element may include a converging lens or one or more asymmetric, aspherical, and / or cylindrical optical elements to provide an oval or elliptical output beam. At least one optical element may include one or more lenses, each lens associated with a single fiber of fiber array 150, a group of fibers within fiber array 150, or all fibers of fiber array 150.

[0054] Each fiber of the fiber array 150 is coupled to a different input of the second optical switch 160. The optical switch 160 can be implemented as an all-optical switch without moving parts, similar to the first optical switch 112. In one embodiment, the optical switch 160 is an M x 1 magneto-optical switch that sequentially connects one of the M inputs of associated fibers coupled within the fiber array 150 to an output that is connected to one or more detectors 164 controlled by one or more associated controllers 162. In one embodiment, the optical switch 160 is a 32 x 1 magneto-optical switch, such that the system 100 provides a 32 x 32 pixel array or data for a 40° horizontal × 20° vertical FOV, as described in more detail herein. Of course, the vertical and horizontal ranges, pixel counts, and FOVs involved do not need to be symmetrical or proportional to the representative embodiment and will vary depending on the application and implementation.

[0055] In one embodiment, at least one controller 120, 160 is a microprocessor-based controller having associated non-transient memory or computer-readable medium for storing data representing instructions executable by one or more controllers to perform one or more control functions or algorithms, and is thereby configured to control a first optical switch 112 to sequentially direct laser pulses from the fiber laser 110 from the input of the first optical switch 112 to each of a plurality of outputs coupled to an associated optical fiber. At least one controller 120, 160 controls a second optical switch 160 to sequentially direct light from each of a second plurality of optical fibers 150 to the output of the second optical switch 160, and processes signals from at least one detector 164 to generate data representing the field of view. Each detector 164 may be implemented by a photodiode such as an avalanche photodiode (APD), a PIN diode, a Schottky barrier photodiode, or any other optical detector with similar sensitivity to provide a desired signal-to-noise ratio (SNR) for a particular application. In cases where more than one controller is provided, the multiple controllers may communicate to exchange data and / or coordinate or cooperate to perform specific tasks, functions, algorithms, etc.

[0056] Generally, the processes, methods, or algorithms disclosed herein can be executed by a processing device, controller, or computer, which may include any existing programmable electronic control unit or dedicated electronic control unit or controller. Similarly, processes, methods, or algorithms can be stored in various forms as data and instructions executable by a controller or computer, including but not limited to information permanently stored on a non-writable storage medium such as a ROM device and information reproducibly stored on a writable storage medium including electronic, magnetic, and / or optical storage devices. Some processes, methods, or algorithms may also be implemented in a software executable object. Alternatively, the processes, methods, or algorithms may be implemented wholly or partially using suitable dedicated or custom hardware components (e.g., application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), state machines, controllers, or any other hardware component or device, or a combination of hardware, software, and firmware components). Similarly, the described operations or results may be performed without requiring a specific order or sequence of description or specification of the processes, algorithms, or functions. For a particular application, certain processes, functions, algorithms, or portions thereof may be repeated, performed in different orders, or omitted.

[0057] Figure 2 This is a diagram showing a cross-section or front view of the transmission bundle of a fiber linear array in a representative embodiment. For example... Figure 2As shown, the optics in the transmitter may not be symmetrical, but rather inherently asymmetrical, aspherical, or cylindrical, such that each beam of output light 118 is shaped by aspherical optics to have an oval or elliptical beam cross-section or front view. Each beam has a very wide angular divergence in the horizontal plane or horizontal direction 220 and a narrow angular divergence in the vertical plane or vertical direction 230, and vice versa. In one embodiment, the horizontal angular divergence is 40 degrees and the vertical angular divergence is 1 degree. This beam shape can be achieved, for example, by placing a small aspherical / cylindrical lens in front of each fiber 114 within the linear array 210, or a larger lens shared by the fiber group or all fibers as described above. In this way, the transmitter guides each laser pulse across a wide horizontal coverage and a narrow vertical coverage, or vice versa. Additional vertical coverage of the FOV is provided by scanning the laser pulse across adjacent fibers using optical switches to cover the desired FOV. Each pulse can be temporally separated to reduce or eliminate overlap.

[0058] Figure 3 This is illustrated in a representative embodiment as a linear array 210 guided relative to transmission fiber 114. Figure 2 A cross-sectional view of the received reflected light in a linear array 310 of orthogonally arranged optical fibers 150. As previously described, the receiver optics are configured to receive laser pulses reflected from the field of view (FOV) and redirect the received reflected light to each optical fiber 150. The fibers are scanned or switched by associated optical switches to guide the received light to one or more detectors. (See also: Regarding...) Figure 1 As described, the received light is guided or coupled to one of a plurality of optical fibers 150 in a linear array 310. The received “beam” in space looks very similar to the emitted beam rotated only 90 degrees, as... Figure 2 and Figure 3 As generally shown in the diagram. Shaping the received light beam into an oval or elliptical cross-section is performed using similar techniques and components as described above with respect to shaping the emitted light beam. In one embodiment, the received light "beams" each cover an angle of 1° in the horizontal direction 220 and an angle of 20° in the vertical direction 230.

[0059] Although orthogonally positioned linear fiber optic arrays are shown as vertical transmission arrays and horizontal receiver arrays, any other orthogonal orientation is possible. Similarly, while representative embodiments include examples of a transmission fiber optic array with 32 fibers and a receiver fiber optic array with 32 fibers, the transmission and receiver arrays may contain different numbers of fibers depending on the specific application. Likewise, although the transmission optics produce a beam with an angular divergence of 40 x 1 degrees and the receiver optics produce light with an angular divergence of 1 x 20 degrees, depending on the specific application, the transmitter and receiver optics can be selected to provide different angular divergences.

[0060] Figure 4 Multidimensional data generated based on detector signals associated with overlap points or pixels corresponding to combinations of emitted and received optical pulses from optical switching or scanning is illustrated. Emitted elliptical pulses 118 are scanned with a transmitter optical switch to sequentially or sequentially guide the pulses into each fiber, as shown in 400. Received light, or "beams," 180 are scanned using receiver optical switches to guide light from each receiver fiber to a detector, as shown in 410. The intersection of the emitted and received beams provides a pixel array 420 representing data generated by detector signals for a specific location / position. Thus, if the transmitter optical switch is configured to guide one or more laser pulses into the fiber indexed i, and the receiver optical switch is configured to guide light received from the fiber indexed j into one or more detectors, the optical signal to be received at the detector will come from the angle defined by the (i,j)th element of the 2D pixel array 420, which is defined by the combination of the emitted and received beams. As defined in more detail below, multiple laser pulses can be supplied to a transmitter / receiver fiber pair before the switch is operated to scan to the next adjacent transmitter / fiber pair, thereby providing multiple measurements for each pixel 420 to improve SNR, as described below. Similarly, switching can occur after each laser pulse, where multiple data associated with each pixel are combined or otherwise processed to provide the desired performance.

[0061] In a representative embodiment, each laser pulse associated with each of the 32 transmission fibers has an instantaneous FOV of 40° x 1°. Each receiver has an instantaneous FOV of 1° x 20°. The laser scans from top to bottom, and the receiver scans from left to right, creating a pixel matrix 420 comprising 32x32 (or more generally N x M) pixels defined by the intersection of the emitted and received beams. The scanning is based on transmitter / receiver optical switching, implemented by 1x32 magneto-optical switches with a switching time of less than 10 μsec. It is assumed that the fiber laser characteristics provide a PRF of 32 x 32 pulses / second or approximately 100 k pulses / second to provide a desired SNR with an average laser power of 100 k x 30 microjoules = 3 W. A representative signal calculation is shown below.

[0062]

[0063] The instantaneous peak power falling on the target is provided by the following formula:

[0064]

[0065] Assuming the target size is related to the minimum detection resolution S of the system tIf they are the same size, the reflected signal from the target object is given by the following formula:

[0066]

[0067] In the worst case, the reflected signal from the target object is uniformly distributed across the half-dome facing the transmitter unit, and therefore the collecting optics in the receiver collect the following amount of power from the target object:

[0068]

[0069] Insert the value of each of the above parameters and give:

[0070]

[0071] While such a signal may be difficult to detect from a single pulse, repeating these pulses to produce sub-pixel measurements per pixel at, for example, a frame rate of 100 Hz can provide a 10-fold improvement in SNR, so the effective received signal would be:

[0072]

[0073] This signal level can be clearly detected by a sensitive photodiode such as an avalanche photodiode or a similar optical detector.

[0074] If the pulses are sufficiently close in time—that is, before the previously emitted pulse has been reflected by the object and detected by the receiver—the laser pulse frequency can be increased using an upper limit system constraint established by the rate at which the emitted pulses overlap or intersect at the receiver. Assuming a buffer time of 2 microseconds (600m) between pulses to prevent pulse mixing, the maximum laser frequency for a typical application would be 500kHz. This repetition rate can provide a corresponding rate of 500K subpixels / second and an average laser power of 15W. Since 15W is a considerable average laser power, multiple detectors can be provided to operate in parallel to cover the system's field of view (FOV). For example, a system with four avalanche photodiodes in parallel, instead of a single detector as described above, facilitates a 125kHz laser (3.8W average laser power) while providing a data rate of 500K subpixels / second. Similarly, a system with eight detectors and a 125kHz laser frequency can produce 1M subpixels / second. Regarding... Figure 9 A representative system with multiple detectors operating in parallel is shown and described. Polarizing filters are omitted, so that all parallel detectors detect the same properties of the received light.

[0075] Alternatively or in combination, search resources can be allocated based on the detection of objects in previous frames. This strategy effectively increases the resolution of detection without increasing the total number of pixels in the system by allocating additional search sub-pixels only for regions where objects were detected in previous frames.

[0076] Figure 5 The illustration shows a modular configuration or architecture of a scanning lidar sensor with a controller or central unit (CU) and at least one optical head (OH) according to a representative embodiment. Unless otherwise stated, Figures 5 to 7 The various modular configurations or architectures shown are understood to have the characteristics related to... Figure 1 The components described in the embodiments are similar to those in the embodiments and will not be described in detail thereafter. However, depending on the specific embodiment, various components may be arranged differently within the CU or OH, and additional components may be used to facilitate a particular embodiment.

[0077] System 500 includes a CU module 510 with a first housing and an OH module 560 in a second housing, coupled via an optical fiber bundle 532. Figure 5 In a representative embodiment, the CU module 510 includes a fiber laser 512, a first optical switch 514, one or more controllers 516, a second optical switch 518, and a detector 520. The fiber laser 512 is coupled to the first optical switch 514 via an optical fiber 522, or may be directly coupled to the first optical switch 514. A transmitter optical fiber 532 is coupled to the output of the first optical switch 514. Similarly, a receiver optical fiber 534 is coupled to the second optical switch 518. A fiber bundle 530 includes the transmitter optical fiber 532 and the receiver optical fiber 534. The OH module 560 includes a transmitter optics 540 and a receiver optics 550. Thus, the OH module 560 contains only optical fibers and optical components and is connected to the CU 510 via the fiber bundle 530. (See reference...) Figures 6 to 7 As shown and described in more detail, multiple OH modules can be connected to a single CU module to extend the system's field of view (FOV). In this embodiment, CU module 510 includes a laser, optical switches, detection electronics, and a processor. OH module 560 is relatively small in size and can be remotely positioned relative to CU module 510. Thus, OH module 560 can be placed in various locations such as vehicles, drones, robots, etc.

[0078] Figure 6A modular configuration or architecture of a scanning lidar sensor with a central unit is illustrated in another representative embodiment, the central unit having an optical splitter coupled upstream of transmitter optical switches of multiple optical heads. System 600 includes multiple OH modules 602 coupled to a remotely positioned CU module 610. CU module 610 includes a laser 612 and an optical fiber splitter 628, which in this representative embodiment is implemented by a 1x4 optical fiber splitter. One or more controllers 616 and one or more detectors 620 may be located within CU module 610 or one or more OH modules 602. In this representative embodiment, the multiple OH modules 602 include four OH modules 660, 662, 664, and 666. Each OH module includes a transmitter optical switch 614, a receiver optical switch 618, a transmitter linear array and associated optics 640, and a receiver linear array and associated optics 650. Thus, system 600 includes one CU 610 and N independent OH modules 602 (four in this example), each covering a specific portion of the system's total field of view (FOV). This architecture maintains the independence of each OH 602 with its own associated scan pattern, but the overall solution may be more expensive and have greater size and complexity.

[0079] Figure 7 A modular configuration or architecture of a scanning lidar sensor with a central unit is shown in another representative embodiment. The central unit has an optical splitter coupled downstream of transmitter optical switches of multiple optical heads. System 700 includes multiple OH modules 702 and a single CU module 710. CU module 710 includes a laser 712 and a transmitter switch 714, the transmitter switch 714 having an output fiber 732 connected to one of a plurality of fiber optic splitters 728. In the representative embodiment shown, 32 1x4 fiber optic splitters 728 are provided such that each fiber optic splitter 728 is coupled to all OH modules 702 via an associated transmission fiber 730. One or more controllers 716 and one or more detectors 720 may also be disposed within CU module 710 or one or more OH modules 702.

[0080] exist Figure 7In one embodiment, the OH module 702 includes a first OH module 760, a second OH module 762, a third OH module 764, and a fourth OH module 766 located remotely from the CU module 710 and coupled via one or more fiber bundles 730. Each OH module 702 includes a receiver optical switch 718, a transmitter linear array and transmitter optics 740, and a receiver linear array and receiver optics 750. In this embodiment, the system 700 includes a single CU module 710 and N non-independent OH modules 702, wherein each scanning step is performed in parallel in each OH module 760, 762, 764, and 766. This is advantageous for smaller OH modules 702 that are generally less expensive, but the scanning pattern for the entire field of view is fixed and is a replica of the scanning pattern of one of the OH modules 702.

[0081] Figure 8 A representative embodiment of a vehicle with a scanning lidar sensor is shown, the scanning lidar sensor having a rotating optical head and / or one or more fixed optical heads. Vehicle 800 includes a plurality of OH modules 802 coupled to a remotely positioned CU module 810. The OH modules can be placed at various locations around vehicle 800, such as OH modules 812, 814 placed on corresponding side mirrors, or OH modules 816, 818 placed on the front grille or bumper. Fixed OH modules can also, or alternatively, be placed at any number of locations including different faces / corners of vehicle 800, interior headlights, frames, mirrors, etc. One or more embodiments may utilize headlight-integrated optics to collect light from the OH units.

[0082] Alternatively, or in combination, vehicle 800 may include an OH module 820 connected to a motor / actuator 830, which rotates to scan 360°, as shown in 840. One or more rotating units may integrate the OH module with a rotating mirror, or transmit light from the OH module via a rotating mirror on the vehicle roof or side. A CU module may transmit laser light to / from the rotating OH module via one or more free-space optical elements without a physical connection between the rotating OH module and the fixed CU module.

[0083] Figure 9This is a block diagram illustrating a scanning lidar with optical switches and multiple detectors for detecting the polarization of reflected light according to various embodiments. System 900 includes a laser 910 configured to emit polarized pulses. In the illustrated embodiment, system 910 includes a polarizer 912 between the laser 910 and the emitter optical switch 914. The polarizer 912 can be omitted if the laser 910 produces polarized light suitable for the application. The optical switch 914, emitter fiber 916, emitter linear array, and optics 918 are configured to maintain the polarization of the polarized pulses to deliver an associated polarized output beam 920 similar to that of the previously described embodiments. Reflected light 930 from an object within the FOV passes through receiver collecting optics and beam-shaping optics and enters a receiver linear array 932 of fiber 934. Switch 936 scans optical fiber 934 to sequentially couple each of the optical fibers 934 to optical splitter 938, which splits or redirects the light to output 940, which is connected to detectors 970, 972, 974, and 976 operating in parallel. Each detector 970, 972, 974, and 976 may have associated polarization filters 950, 952, 954, and 956 to detect light with a corresponding polarization.

[0084] like Figure 9 As shown, each emitted laser pulse through fiber 916 is polarized, and the system's collecting optics, including free-space optical elements 918, 932 and receiving fiber 934, are selected to maintain the polarization of the reflected signal from the target object. Thus, system 900 can collect information not only about the reflectivity or shape of the target object, but also about its degree of polarization (DOP) and angle of polarization (AOP). Because each detector 970, 972, 974, and 976 has different linear polarizers 950, 952, 954 or circular polarizers 956 aligned at angles of 0 degrees, 45 degrees, and 90 degrees in front of its front surface, the different polarization components of each reflected signal can be used to calculate the DOP and AOP of natural and / or man-made targets with great accuracy. DOP / AOP information can be used in driver assistance systems and autonomous vehicles.

[0085] AOP and / or DOP images are highly robust and can withstand strong atmospheric interference, such as scattering through fog, mist, or rain. Under such atmospheric conditions, the intensity of reflected signals from a target tends to decrease and is masked by light reflected and scattered by particles or water droplets in its optical path. However, DOP / AOP information from the target is preserved, and therefore can be used to sense or see through fog and mist over a longer range, compared to simple intensity information. Polarization information can also help detect and classify small objects on smooth surfaces (such as flat tires or potholes or cracks in the road), which are almost impossible to detect using only intensity images of reflected signals. Polarization information can also help detect and classify surface features to warn drivers, such as road surfaces containing water, oil, ice, black ice, etc.

[0086] Figure 10 A representative embodiment of a system or method for generating subpixel data by manipulating or scanning the polarization of emitted and received light in a laser scanning field of view (FOV) using a Faraday rotator and a phase mask. This strategy can be used in one or more of the foregoing embodiments or other laser scanning systems to increase the resolution of the system scan. The system or method includes inserting a polarization phase mask and polarization manipulation components into the light columns of both emitted and received light. Polarization manipulation can be performed electronically such that there are no moving parts during the scanning process, as previously described with respect to one or more embodiments. Within the scope of the claimed subject matter and as those skilled in the art will recognize, in addition to Figure 10 In addition to those shown, there are various other ways to provide polarization manipulation within the optical path of the emitted and received beams.

[0087] System 1000 includes an optical path 1020 for emitting and receiving a light beam. Optical path 1020 includes a linear polarizer 1022 positioned upstream of a Faraday rotator (FR) 1024, which in turn is positioned upstream of a phase mask (PM) 1028 and a second linear polarizer 1050. For example, in any of the previously described embodiments, system 1000 may be positioned in front of each transmitting fiber.

[0088] Phase mask 1028 may include a liquid crystal polymer (LCP) retarder, which is a half-wave retarder designed to influence the radial and azimuth polarization of the light field. For example, commercially available eddy current retarders have a constant delay over the transparent aperture, but their fast axis rotates continuously over the optical device region. There are no practical limitations on flexibility in designing the fast axis distribution on the phase mask to generate the desired polarized light distribution directly downstream of the phase mask. Figure 10In a representative embodiment, phase mask 1028 is a half-wave delayer phase mask comprising three columns 1030, 1032, and 1034, each column having a delay axis rotated at a different angle. This design allows Faraday rotator (FR) 1024 to rotate or align the input linear polarization generated by linear polarizer 1022 parallel to one of the delay axes 1030, 1032, and 1034 on phase mask 1028. FR 1024 is electronically controlled by providing a variable voltage. If the selected polarization direction is parallel to the delay axis in the first column 1030 of PM, the intensity of light following the second polarizer 1050 will have a peak intensity along the line of column 1030, with the intensity decreasing toward columns 1032 and 1034 having axes rotated relative to the input polarizer 1022. FR 1024 can then select a second rotation angle to align the polarization with the second column 1032 of PM 1028. In this configuration, the peak intensity after the second polarizer 1050 will shift to the second column 1032, while the other columns 1030, 1034 will have lower intensity and appear darker. Similarly, the FR 1024 can select any column 1030, 1032, 1034 whose intensity should be enhanced after the second polarizer 1050, and thus "scan" the peak intensity horizontally with three sub-pixels. Similar optics can be placed in front of the system's receiving channel using the same scanning mechanism, but the receiver PM is rotated 90 degrees relative to the transmitting PM. This allows the transmitter / receiver to enhance different squares in the PM based on nine possible sub-pixels of the field of view per fiber, and thus different portions of the selected pixel. This strategy can be applied to single-pixel positioning to provide sub-pixel resolution by scanning the polarization through the PM using the FR, resulting in scanning the peak intensity of the received pulse within a pixel rather than a portion or region of the FOV represented by a group of pixels.

[0089] The combination of transmitter and receiver polarization scanning modes provides emphasis on specific pixels within a pixel group or, for example... Figure 11 In general, it refers to the power capability of a specific region within a single pixel.

[0090] Reference Figure 10 and Figure 11Mode 1110 represents the peak intensity distribution of the emitted beam with system 1000 in the optical path after the light leaves the second polarizer 1050, where FR 1024 is controlled to align with the first column 1030 of PM 1028. This results in column 1120 having a higher peak intensity relative to columns 1122 and 1124. Mode 1130 represents the peak intensity distribution of the received light with system 1000 in the optical path after the received light leaves the polarizer 1050, but PM 1028 is rotated 90 degrees, and FR is controlled in a coordinated manner as FR in the transmission path. This results in the top row 1132 having a higher peak intensity than the middle row 1134 and the bottom row 1136. Combined emitter / receiver scan 1150 shows the resulting power or intensity distribution, where pixel or sub-pixel 1152 has a higher peak intensity than the surrounding sub-pixels / pixels. By switching or scanning the polarization state, the position of the brightest pixel or sub-pixel can be rapidly moved to various positions, thereby scanning the region of interest with variable intensity and improving resolution.

[0091] Figure 12 This is a flowchart illustrating the operation of a system or method for performing lidar scanning using optical switching according to one or more embodiments. System or method 1200 includes generating a laser pulse at 1210, which may include generating the laser pulse using a fiber laser having a nominal output wavelength between 900 nm and 1700 nm. At 1220, the system or method includes optically switching the laser pulse to each of a first plurality of optical fibers arranged in a first linear array to illuminate a field of view. This may include shaping the laser pulse to form an elliptical beam that diverges at an angle along a first axis at least 20 times larger than its angular divergence along a perpendicular second axis, as shown at 1222.

[0092] Box 1230 indicates that light reflected from an object illuminated by a laser pulse within the field of view is directed to a second plurality of optical fibers arranged in a second linear array. This may include collecting the light at 1232 and shaping the light to form an elliptical beam with an angular divergence along a second axis that is at least 20 times larger than the angular divergence along a perpendicular first axis. The system or method may also include optically switching the light from the second plurality of optical fibers to direct the light to at least one detector, as shown at 1240. This processing may include optically splitting the received light to direct a portion of the received light to each of a plurality of detectors arranged in parallel, as shown at 1242. The system or method may also include detecting the polarization angle and / or degree of polarization of the received light, as shown at 1244. The detector signals are then processed to generate data representing the field of view, as shown at box 1250.

[0093] Figure 13This is a flowchart illustrating the operation of a system or method for increasing the resolution of a laser-scanned field of view (FOV) using polarization manipulation according to one or more embodiments. System or method 1300 includes generating a laser beam at 1310, which may be a pulsed or continuous-wave (CW) beam. The laser beam is scanned along a first direction to generate an emitted beam to illuminate the field of view, as shown at 1320. This may include optically switching the laser beam to scan a first linear array of optical fibers, as shown at 1322.

[0094] System or method 1300 may include guiding light reflected from an object illuminated by an emitted laser beam within a field of view along a second direction orthogonal to a first direction to form a received beam provided to at least one detector, as shown at 1330. This may include optically switching the light received from a linear fiber array orthogonally positioned relative to a first linear fiber array, as shown at 1332. Box 1340 represents processing signals from at least one detector to generate a two-dimensional array of pixels. Box 1350 represents altering the intensity distribution within a selected pixel or group of pixels by synchronously changing the polarization of the emitted laser beam and the received beam provided to at least one detector to move the peak intensity in a continuous manner within the selected pixel or across the entire group of pixels. This may include guiding the emitted and received beams through associated polarizers, Faraday rotators, and phase masks, as shown at 1352, and synchronously controlling the Faraday rotator to manipulate or change the polarization, as shown at 1354.

[0095] While representative embodiments have been described above, these embodiments are not intended to describe all possible forms of the claimed subject matter. The language used in this specification is descriptive rather than restrictive, and it should be understood that various changes may be made without departing from the spirit and scope of this disclosure and the claimed subject matter. Furthermore, features of various implementation embodiments may be combined to form further embodiments not explicitly described or shown but within the scope of this disclosure and the claimed subject matter and recognizable by those skilled in the art.

[0096] While various embodiments may be described as offering advantages or superiority over other embodiments or prior art implementations with respect to one or more desired characteristics, those skilled in the art will recognize that one or more features or characteristics can be compromised to achieve desired overall system properties, depending on the specific application and implementation. These properties include, but are not limited to, cost, strength, durability, life cycle cost, marketability, appearance, packaging, size, serviceability, weight, manufacturability, ease of assembly, etc. Embodiments described with respect to one or more characteristics as less desirable than those desired by other embodiments or prior art implementations are not necessarily outside the scope of this disclosure and may be desired for a particular application.

Claims

1. A scanning lidar system, comprising: A transmitter, the transmitter including a laser and a first optical switch configured to receive laser pulses from the laser; The first plurality of optical fibers, each optical fiber being coupled to a different output among the plurality of outputs of the first optical switch; A first at least one optical element, the first at least one optical element being configured to receive the laser pulse from at least one of the first plurality of optical fibers and redirect the laser pulse to illuminate at least a portion of the field of view; The receiver includes a second optical switch and at least one detector; The second plurality of optical fibers, each optical fiber being coupled to a different input of the second optical switch, and the output of the second optical switch being coupled to the at least one detector; A second at least one optical element, configured to receive laser pulses reflected from the field of view and redirect the received reflected pulses to at least one of the second plurality of optical fibers; as well as At least one controller is configured to control the first optical switch to sequentially direct the laser pulse from the input of the first optical switch to each of the plurality of outputs, control the second optical switch to sequentially direct light from each of the second plurality of optical fibers to the output of the second optical switch, and process signals from the at least one detector to generate data representing the field of view. The outputs of the first plurality of optical fibers are located in a first linear array, and the inputs of the second plurality of optical fibers are located in a second linear array orthogonal to the first linear array. The first at least one optical element is configured to form a pulsed output beam with an elliptical cross-section from each of the first plurality of optical fibers. The second at least one optical element is configured to form a receiving pulse beam with an elliptical cross-section. The data corresponds to pixels, and each pixel corresponds to the intersection of a transmitted pulse beam and a received pulse beam with an elliptical cross-section.

2. The scanning lidar system according to claim 1, wherein, The first optical switch and the second optical switch do not have moving parts that are respectively associated with switching light from an input to one of a plurality of outputs or from a plurality of outputs to an input.

3. The scanning lidar system according to claim 1 or 2, wherein, At least one of the first optical switch and the second optical switch includes a Faraday rotator.

4. The scanning lidar system according to claim 1 or 2, wherein, At least one of the first optical switch and the second optical switch includes a magneto-optical switch.

5. The scanning lidar system according to claim 1 or 2, wherein, The at least one controller includes a first microprocessor-based controller configured to control the first optical switch and a second microprocessor-based controller communicating with the first controller and configured to control the second optical switch.

6. The scanning lidar system according to claim 1 or 2, wherein, The laser includes a fiber laser configured to generate pulses with wavelengths between 900 nm and 1700 nm.

7. The scanning lidar system according to claim 1 or 2, wherein, The laser is configured to generate pulses with a nominal wavelength of 1550 nm.

8. The scanning lidar system according to claim 1 or 2, wherein, The first at least one optical element includes an aspherical lens configured to form a pulsed output beam with an elliptical cross-section.

9. The scanning lidar system according to claim 8, wherein, The first at least one optical element is shaped to form a pulsed output beam that diverges at an angle along the first axis by at least 20 times the angle along the second axis perpendicular to the first axis.

10. The scanning lidar system according to claim 8, wherein, The first at least one optical element includes a plurality of optical elements, each of which is associated with one of the plurality of optical fibers.

11. The scanning lidar system according to any one of claims 1, 2, 9 or 10, wherein, The second at least one optical element includes a collecting optics located upstream of a beam-forming optics configured to form a pulsed beam with an elliptical cross-section.

12. The scanning lidar system according to claim 11, wherein, A pulsed beam with an elliptical cross-section diverges at an angle along the second axis that is at least 20 times greater than it diverges at an angle along the first axis that is perpendicular to the second axis.

13. The scanning lidar system according to any one of claims 1, 2, 9, 10 or 12, wherein, The at least one detector includes an avalanche photodiode.

14. The scanning lidar system according to claim 13, wherein, The at least one detector includes a plurality of detectors configured to operate in parallel.

15. The scanning lidar system according to any one of claims 1, 2, 9, 10, 12 or 14, wherein, The laser is configured to emit polarized pulses, and the detector includes a plurality of detectors, each configured to detect received light with different polarization angles.

16. The scanning lidar system according to claim 15, wherein, The at least one controller processes signals from the plurality of detectors to generate polarization degree or polarization angle data representing the field of view.

17. The scanning lidar system according to claim 15, wherein, The first at least one optical element and the second at least one optical element each include a polarization rotator and a polarization phase mask controlled by the at least one controller.

18. The scanning lidar system according to claim 15, wherein, The first at least one optical element and the second at least one optical element each include a first linear polarizer, a Faraday rotator, a half-wave delay phase mask, and a second linear polarizer.

19. The scanning lidar system according to any one of claims 1, 2, 9, 10, 12, 14, 16-18, wherein, The at least one controller is also configured to operate the laser, as well as the first and second optical switches, to refresh data at 100 Hz.

20. The scanning lidar system according to any one of claims 1, 2, 9, 10, 12, 14, 16-18, further comprising a housing and at least one optical head, the housing containing the transmitter, the receiver, and the at least one controller, the at least one optical head being located outside the housing and containing the first at least one optical element and the second at least one optical element, wherein, The first plurality of optical fibers and the second plurality of optical fibers extend between the first housing and the optical head.

21. The scanning lidar system according to claim 20, wherein, The housing contains a transmitter and a receiver associated with each of a plurality of remotely positioned optical heads, each optical head being coupled via an associated fiber bundle.

22. A vehicle comprising a scanning lidar system according to claim 20 or 21.

23. The vehicle of claim 22, further comprising an actuator configured to rotate at least one of the optical heads.

24. A method, the method comprising: Generate laser pulses; The laser pulse is optically switched to each of the first plurality of optical fibers arranged in a first linear array to illuminate the field of view; The light reflected from the object illuminated by the laser pulse within the field of view is guided to a second plurality of optical fibers arranged in a second linear array; Optically switch light from the second plurality of optical fibers to direct the light to at least one detector; and The signals from the detector are processed to generate data representing the field of view. The method further includes shaping laser pulses output from the first plurality of optical fibers to form an output pulse beam with an elliptical cross-section, and shaping received laser pulses guided into the second linear array into a received pulse beam with an elliptical cross-section. The first linear array and the second linear array are positioned orthogonally. The data corresponds to pixels, and each pixel corresponds to the intersection of a transmitted pulse beam and a received pulse beam with an elliptical cross-section.

25. The method according to claim 24, wherein, Generating laser pulses involves using fiber lasers with output wavelengths between 900 nm and 1700 nm.

26. The method according to claim 24 or 25, wherein, Optically switching the laser pulse and optically switching at least one of the second plurality of optical fibers includes controlling a magneto-optical switch.

27. The method according to claim 24 or 25, wherein the output pulse beam having an elliptical cross-section diverges at an angle along the first axis at least 20 times greater than the angle divergence along a second axis perpendicular to the first axis.

28. The method according to claim 24 or 25, wherein, The at least one detector is only one detector, and wherein optically switching light from the second plurality of optical fibers includes optically switching light to a single optical fiber coupled to the detector.

29. The method according to claim 24 or 25, wherein, The at least one detector includes a plurality of detectors, and wherein optically switching light from the second plurality of optical fibers includes optically switching light from different groups of optical fibers to different detectors operating in parallel.

30. The method according to claim 24 or 25, further comprising: To polarize the laser pulse illuminating the field of view; Detect the polarization of light reflected from the object irradiated by the laser pulse; as well as Polarization data representing the field of view is generated based on the detection of the polarization of light reflected from the object.

31. The method of claim 30, further comprising changing the polarization of the laser pulse such that the light intensity detected from the selected fiber in the second plurality of optical fibers increases relative to the light intensity from the fiber adjacent to the selected fiber.

Images