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 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 light from one of the emitted pulses of light that is scattered by a target located a distance from the lidar system. The local-oscillator light and the received pulse of light are coherently mixed together at the receiver. The lidar system further includes a processor configured to determine the distance to the target based at least in part on a time-of-arrival for the received pulse of light.

Abstract: In one embodiment, a lidar system includes a light source configured to emit local-oscillator (LO) light and pulses of light, the emitted pulses of light including a first emitted pulse of light, where an optical frequency of the first emitted pulse of light is offset from an optical frequency of the LO light by a first frequency offset. The lidar system further includes a receiver configured to detect the LO light and a first received pulse of light, the first received pulse of light including light from the first emitted pulse of light scattered by a target located a distance from the lidar system. The receiver includes a detector, where: the LO light and the first received pulse of light are coherently mixed together at the detector, and the detector is configured to produce a photocurrent signal corresponding to the coherent mixing.

Abstract: In one embodiment, a lidar system includes a wavelength-tunable light source configured to emit pulses of light, each emitted pulse of light having a particular wavelength of multiple different wavelengths. The lidar system also includes a scanner configured to scan the emitted pulses of light across a field of regard of the lidar system. The scanner includes (i) a beam deflector configured to angularly deflect each emitted pulse of light along a first scan axis according to the particular wavelength of the emitted pulse of light and (ii) a scan mirror configured to scan the emitted pulses of light along a second scan axis different from the first scan axis. The lidar system further includes a receiver configured to detect a received pulse of light that includes a portion of one of the emitted pulses of light scattered by a target located a distance from the lidar system.

Abstract: In one embodiment, a method for dynamically varying receiver characteristics in a lidar system includes emitting light pulses by a light source in a lidar system. The method further includes detecting, by a receiver in the lidar system, light from one of the light pulses scattered by one or more remote targets to identify a return light pulse. The method also includes determining an atmospheric condition at or near a geolocation of a vehicle that includes the lidar system. The method further includes providing a control signal to the receiver adjusting one or more characteristics of the receiver to compensate for attenuation or distortion of the return light pulses associated with the atmospheric condition.

Abstract: In one embodiment, a lidar system includes a light source, a receiver, and a controller. The light source is configured to emit an optical signal. The receiver is configured to detect a received optical signal that includes a portion of the emitted optical signal that is scattered by a surface of a target located a distance from the lidar system, where the surface is oriented at an angle of incidence with respect to the emitted optical signal. The receiver is further configured to produce an electrical signal corresponding to the received optical signal. The controller is configured to determine, based on the electrical signal, the angle of incidence of the surface of the target.

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 across a field of regard of the lidar system. The scanner includes (i) a beam deflector configured to direct each emitted pulse of light along a first scan axis and (ii) a scan mirror configured to scan the emitted pulses of light along a second scan axis different from the first scan axis. The lidar system also includes a receiver that includes a one-dimensional detector array that includes multiple detector elements arranged along a direction corresponding to the first scan axis. The receiver is configured to (i) detect a received pulse of light that includes a portion of one of the emitted pulses of light scattered by a target and (ii) determine a time of arrival of the received pulse of light.

Abstract: In one embodiment, a lidar system includes a light source configured to emit pulses of light, where each emitted pulse of light includes a spectral signature of multiple different spectral signatures. The lidar system also includes a receiver configured to detect 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 emitted pulse of light includes one of the spectral signatures. The receiver includes a detector configured to produce a photocurrent signal corresponding to the received pulse of light, a frequency-detection circuit configured to determine, based on the photocurrent signal, a spectral signature of the received pulse of light, and a pulse-detection circuit configured to determine, based on the photocurrent signal, a time-of-arrival of the received pulse of light.

Abstract: In one embodiment, a lidar system includes a light source configured to emit (i) local-oscillator light and (ii) pulses of 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 a coherent mixing of the local-oscillator light and the received pulse of light. The detector includes a first input side and a second input side located opposite the first input side, where the received pulse of light is incident on the first input side of the detector, and the local-oscillator light is incident on the second input side of the detector.

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 portion of the local-oscillator light. The light source includes a seed laser configured to produce seed light and the local-oscillator light. The light source also includes a pulsed optical amplifier configured to amplify temporal portions of the seed light to produce the emitted pulses of light, where each amplified temporal portion of the seed light corresponds to one of the emitted pulses of 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 light from one of the emitted pulses of light that is scattered by a target located a distance from the lidar system.

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: A lidar system identifies anomalous optical pulses received by the lidar system. The lidar system includes a light source configured to output a plurality of transmitted pulses of light, each transmitted pulse of light having one or more representative characteristics, a scanner configured to direct the plurality of transmitted pulses of light to a plurality of locations within a field of regard, and a receiver configured to detect a plurality of received pulses of light from the field of regard. The lidar system is configured to identify an anomalous pulse amongst the plurality of received pulses of light based on its having at least one characteristic that does not correspond to the one or more representative characteristics of the plurality of transmitted pulses of light.

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: 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 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: 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 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 lidar system includes a light source configured to emit an output optical signal and a local-oscillator optical signal. The output optical signal includes (i) pulses of light and (ii) frequency-modulated (FM) output-light signals, where each pair of consecutive pulses of light is separated in time by one or more of the FM output-light signals. The local-oscillator optical signal includes FM local-oscillator light signals corresponding to the FM output-light signals. The lidar system also includes a receiver configured to detect the local-oscillator optical signal and an input optical signal. The input optical signal includes (i) a received pulse of light that includes a portion of one of the emitted pulses of light scattered by a target located a distance from the lidar system and (ii) a received FM light signal that includes a portion of one of the FM output-light signals scattered by the target.

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.