Abstract: In one embodiment, a lidar system includes a light source configured to emit local-oscillator light and pulses of light, where each emitted pulse of light is (i) coherent with a corresponding portion of the local-oscillator light and (ii) includes a spectral signature of one or more different spectral signatures. The lidar system also includes a receiver configured to detect the local-oscillator light and a received pulse of light, the received pulse of light including light from one of the emitted pulses of light scattered by a target located a distance from the lidar system, the one of the emitted pulses of light including a particular spectral signature of the one or more spectral signatures. The local-oscillator light and the received pulse of light are coherently mixed together at the receiver. The receiver includes one or more detectors and a frequency-detection circuit.

Abstract: In one embodiment, a lidar system includes a light source configured to emit pulses of light and a scanner configured to scan at least a portion of the emitted pulses of light along a scan pattern contained within an adjustable field of regard. The scanner includes a first scanning mirror configured to scan the portion of the emitted pulses of light substantially parallel to a first scan axis to produce multiple scan lines of the scan pattern. The scanner also includes a second scanning mirror configured to distribute the scan lines along a second scan axis, where the scan lines are distributed within the adjustable field of regard according to an adjustable second-axis scan profile that includes a minimum scan angle along the second scan axis, a maximum scan angle along the second scan axis, and a scan-line distribution.

Abstract: In one embodiment, a lidar system includes a light source configured to emit (i) local-oscillator light and (ii) pulses of light. Additionally, the light source is configured to impart a spectral signature of one or more different spectral signatures to each of the emitted pulses of light, where the emitted pulses of light include an emitted pulse of light having a particular spectral signature of the one or more different spectral signatures. The lidar system also includes a receiver configured to detect the local-oscillator light and a received pulse of light, the received pulse of light including a portion of the emitted pulse of light scattered by a target located a distance from the lidar system. The receiver includes a detector configured to produce a photocurrent signal corresponding to the local-oscillator light and the received pulse of light. The receiver also includes a pulse-detection circuit and a frequency-detection circuit.

Abstract: To dynamically control power in a lidar system, a controller identifies a triggering event and provides a control signal to a light source in the lidar system adjusting the power of light pulses provided by the light source. Triggering events may include exceeding a threshold speed, being within a threshold distance of a person or other object, an atmospheric condition, identifying residue on a surface of a window of the lidar system, etc. In some scenarios, the power is adjusted to address eye-safety concerns.

Abstract: In one embodiment, a lidar system includes a light source configured to emit (i) local-oscillator light and (ii) pulses of light, where each emitted pulse of light is coherent with a corresponding temporal portion of the local-oscillator light. The lidar system also includes a receiver configured to detect the local-oscillator light and a received pulse of light, the received pulse of light including a portion of one of the emitted pulses of light scattered by a target located a distance from the lidar system. The receiver includes a detector configured to produce a photocurrent signal corresponding to the local-oscillator light and the received pulse of light. The photocurrent signal includes a sum of a first term, a second term, and a third term.

Abstract: In one embodiment, a lidar system includes a light source configured to emit a pulse of light and a scanner configured to direct the emitted pulse of light into a field of regard of the lidar system. The lidar system also includes a receiver configured to receive a portion of the emitted pulse of light scattered by a target located a distance from the lidar system. The receiver includes a digital micromirror device (DMD) that includes a two-dimensional array of electrically addressable micromirrors, where a portion of the micromirrors are configured to be set to an active-on state to direct the received pulse of light to a detector array. The detector array includes a two-dimensional array of detector elements, where the detector array is configured to detect the received pulse of light and produce an electrical signal corresponding to the received pulse of light.

Abstract: In one embodiment, a lidar system includes a light source configured to emit an optical signal that is directed into a field of regard (FOR) of the lidar system. The lidar system also includes a receiver configured to: receive a portion of the emitted optical signal scattered by a target located in the FOR a distance from the lidar system; and produce an electrical signal corresponding to the received optical signal, where the electrical signal is related to a preliminary value of an optical characteristic of the received optical signal. The lidar system further includes a processor coupled to the receiver and configured to: determine the distance to the target; receive a humidity value; and determine a corrected value of the optical characteristic of the received optical signal based at least in part on the electrical signal produced by the receiver, the distance to the target, and the humidity value.

Abstract: In one embodiment, a lidar system includes a light source configured to emit pulses of light and a scanner configured to scan at least a portion of the emitted pulses of light across a field of regard. The field of regard contains all or part of a target located a distance from the lidar system that is less than or equal to a maximum range of the lidar system, and one or more of the emitted pulses of light are scattered by the target. The lidar system also includes a receiver configured to detect at least a portion of the pulses of light scattered by the target. The lidar system further includes a processor configured to determine the distance from the lidar system to the target based at least in part on a round-trip time of flight for an emitted pulse of light.

Abstract: To compensate for the uneven distribution of data points around the periphery of a vehicle in a lidar system, a light source transmits light pulses at a variable pulse rate according to the orientation of the light pulses with respect to the lidar system. A controller may communicate with a scanner in the lidar system that provides the orientations of the light pulses to the controller. The controller may then provide a control signal to the light source adjusting the pulse rate based on the orientations of the light pulses. For example, the pulse rate may be slower near the front of the lidar system and faster near the periphery. In another example, the pulse rate may be faster near the front of the lidar system and slower near the periphery.

Abstract: In one embodiment, a lidar system includes a multi junction light source configured to emit an optical signal. The multi junction light source includes a seed laser diode configured to produce a seed optical signal and a multi junction semiconductor optical amplifier (SOA) configured to amplify the seed optical signal to produce the emitted optical signal. The lidar system also includes a receiver configured to detect a portion of the emitted optical signal scattered by a target located a distance from the lidar system. The lidar system further includes a processor configured to determine the distance from the lidar system to the target based on a round-trip time for the portion of the scattered optical signal to travel from the lidar system to the target and back to the lidar system.

Abstract: A lidar system includes a light source, a scanner, and a receiver and is configured to detect remote targets located up to RMAX meters away. The receiver includes a detector with a field of view larger than the light-source field of view. The scanner causes the detector field of view to move relative to the instantaneous light-source field of view along the scan direction, so that (i) when a pulse of light is emitted, the instantaneous light-source field of view is approximately centered within the detector field of view, and (ii) when a scattered pulse of light returns from a target located RMAX meters away, the instantaneous light-source field of view is located near an edge of the field of view of the detector and is contained within the field of view of the detector.

Abstract: In one embodiment, a lidar system includes a light source configured to emit light at one or more wavelengths between 1200 nm and 1400 nm. The lidar system also includes a scanner configured to scan the emitted light across a field of regard of the lidar system and a receiver configured to detect a portion of the emitted light scattered by a target located a distance from the lidar system. The lidar system further includes a processor configured to determine the distance from the lidar system to the target based at least in part on a round-trip time for the portion of the emitted light to travel from the lidar system to the target and back to the lidar system.

Abstract: In one embodiment, a lidar system includes a light source configured to emit pulses of light and a scanner configured to scan at least a portion of the emitted pulses of light along a scan pattern contained within an adjustable field of regard. The scanner includes a first scanning mirror configured to scan the portion of the emitted pulses of light substantially parallel to a first scan axis to produce multiple scan lines of the scan pattern, where each scan line is oriented substantially parallel to the first scan axis. The scanner also includes a second scanning mirror configured to distribute the scan lines along a second scan axis that is substantially orthogonal to the first scan axis, where the scan lines are distributed within the adjustable field of regard according to an adjustable second-axis scan profile.

Abstract: To dynamically control power in a lidar system, a controller identifies a triggering event and provides a control signal to a light source in the lidar system adjusting the power of light pulses provided by the light pulse. Triggering events may include exceeding a threshold speed, being within a threshold distance of a person or other object, an atmospheric condition, etc. In some scenarios, the power is adjusted to address eye-safety concerns.

Abstract: In one embodiment, a lidar system includes a light source configured to emit an optical signal and a receiver configured to detect an input optical signal that includes a portion of the emitted optical signal scattered by a target located a distance from the lidar system. The receiver includes an avalanche photodiode (APD) configured to receive the input optical signal and produce a photocurrent signal corresponding to the input optical signal. The APD includes a multiplication region that includes a digital-alloy region that includes two or more semiconductor alloy materials arranged in successive layers. The digital-alloy region is configured to produce at least a portion of the photocurrent signal by impact ionization. The receiver is configured to determine, based on the photocurrent signal produced by the APD, a round-trip time for the portion of the emitted optical signal to travel to the target and back to the lidar system.

Abstract: In one embodiment, a lidar system includes a light source configured to emit pulses of light and a scanner configured to scan the emitted pulses of light along a high-resolution scan pattern located within a field of regard of the lidar system. The scanner includes one or more scan mirrors configured to (i) scan the emitted pulses of light along a first scan axis to produce multiple scan lines of the high-resolution scan pattern, where each scan line is associated with multiple pixels, each pixel corresponding to one of the emitted pulses of light and (ii) distribute the scan lines of the high-resolution scan pattern along a second scan axis. The high-resolution scan pattern includes one or more of: interlaced scan lines and interlaced pixels.

Abstract: In one embodiment, a lidar system includes a light source configured to emit an optical signal and a receiver that includes one or more detectors configured to detect a portion of the emitted optical signal scattered by a target located a distance from the lidar system. The lidar system also includes a photonic integrated circuit (PIC) that includes an input optical element configured to receive the portion of the scattered optical signal and couple the portion of the scattered optical signal into an input optical waveguide. The input optical waveguide is one of one or more optical waveguides of the PIC configured to convey the portion of the scattered optical signal to the one or more detectors of the receiver. The input optical element includes a grating coupler and a tapered optical waveguide.

Abstract: In one embodiment, a light source is configured to emit an optical signal. The light source includes a seed laser diode configured to produce a seed optical signal and a semiconductor optical amplifier (SOA) configured to amplify the seed optical signal to produce the emitted optical signal. The light source also includes an optical isolator disposed between the seed laser diode and the SOA, where the optical isolator is configured to (i) transmit the seed optical signal to the SOA and (ii) reduce an amount of light that propagates from the SOA toward the seed laser diode.

Abstract: In one embodiment, a light source is configured to emit an optical signal. The light source includes a seed laser diode configured to produce a seed optical signal and a semiconductor optical amplifier (SOA) configured to amplify the seed optical signal to produce the emitted optical signal. The SOA includes an optical waveguide extending along a longitudinal direction from an input end of the SOA to an output end of the SOA. The optical waveguide is configured to guide and provide optical gain to the seed optical signal while the seed optical signal propagates in the longitudinal direction along the optical waveguide from the input end to the output end. The SOA also includes a Bragg grating disposed parallel to the optical waveguide, where the Bragg grating includes a region of the SOA having a refractive index that varies along the longitudinal direction.

Abstract: A system operating in a vehicle includes a lidar module, a camera, and a controller communicatively coupled to the camera and the lidar module. The lidar module includes: a light source configured to emit pulses of light, a scanner configured to direct the emitted pulses of light in accordance with a scan pattern to illuminate a field of regard of the lidar module, and a receiver configured to detect the emitted pulses of light scattered by one or more remote objects to capture a set of lidar pixels of a scan frame, in a sequence defined by the scan pattern. The camera has a field of view that at least partially overlaps the field of regard of the lidar module. The controller is configured to cause the camera to capture multiple images while the receiver of the lidar module captures the set of lidar pixels of the scan frame.