Abstract: A lidar system includes one or more light sources configured to emit light pulses, a scanner configured to direct the emitted light pulses as beams along one or more scan directions to illuminate, for each orientation of the scanner with each of the plurality of beams, a respective light-source field of view corresponding to a respective pixel, and a receiver configured to detect the light pulses scattered by one or more remote targets. The receiver includes a first, second, and third detectors to detect light pulses associated with respective beams. Each detector has a separate detector field of view within which the detector receives scattered light. A spatial separation between the first detector and the second detector is greater than a spatial separation between the second detector and the third detector.

Abstract: A lidar system includes a light source configured to emit light pulses and a receiver configured to detect light from some of the light pulses scattered by remote targets. The receiver includes an avalanche photodiode operating in the linear mode for detecting the light pulses. To prevent damage to the linear mode avalanche photodiode a quench circuit is coupled to the avalanche photodiode, where the quench circuit reduces a bias voltage applied to the avalanche photodiode, when an avalanche event occurs at the avalanche photodiode.

Abstract: To decrease the likelihood of a false detection when detecting light from light pulses scattered by remote targets in a lidar system, a receiver in the lidar system includes a photodetector and a pulse-detection circuit having a gain circuit with a varying amount of gain over time. The gain circuit operates in a low-gain mode for a time period T1 beginning with time t0 when a light pulse is emitted to prevent the receiver from detecting return light pulses during the threshold time period T1. Upon expiration of the threshold time period T1, the gain circuit operates in a high-gain mode to begin detecting return light pulses until a subsequent light pulse is emitted.

Abstract: To detect light from light pulses at the operating wavelength of a light source in a lidar system, a thin-film notch filter is directly deposited on a photodetector or a lens via vacuum deposition or monolithic epoxy. The thin-film notch filter may include an anti-reflective coating such as a pattern-coated dichroic filter having an optical transmission of 90% or greater at in-band wavelengths and less than 5% at out-of-band wavelengths. To deposit the filter onto the photodetector without disrupting electronic connections between the photodetector and an application-specific integrated circuit, the area surrounding the electrodes on the photodetector is kept open using photolithography.

Abstract: To compensate for motor dynamics in a scanner in a lidar system, a light source transmits light pulses at a variable pulse rate in accordance with a scan speed of the scanner. More specifically, the pulse rate may be directly related to the scan speed so that the light source transmits light pulses uniformly across a field of regard. A controller may determine the scan speed and provide a control signal to the light source adjusting the pulse rate accordingly.

Abstract: A lidar system is disclosed. The lidar system can include a light source to produce first and second sets of pulses of light. The system can also include a first lidar sensor with a first scanner to scan the first set of pulses of light along a first scan pattern, and a first receiver to detect scattered light from the first set of pulses of light. The system can also include a second lidar sensor with a second scanner to scan the second set of pulses of light along a second scan pattern, and a second receiver to detect scattered light from the second set of pulses of light. The first scan pattern and the second scan pattern can be at least partially overlapped in an overlap region. The lidar system can also include an enclosure to contain the light source, the first lidar sensor, and the second lidar sensor.

Abstract: A lidar system can include a solid-state laser to emit pulses of light. The solid-state laser can include a Q-switched laser having a gain medium and a Q-switch. The lidar system can also include a scanner configured to scan the emitted pulses of light across a field of regard and a receiver configured to detect at least a portion of the scanned pulses of light scattered by a target located a distance from the lidar system. The lidar system can also include 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 to travel from the lidar system to the target and back to the lidar system.

Abstract: To detect return light pulses in a lidar system when scanning in the forward-scanning and reverse-scanning directions, a light source may transmit first light pulses having a first wavelength when scanning in the forward-scanning direction and may transmit second light pulses having a second wavelength when scanning in the reverse-scanning direction. A diffractive optical element (DOE) is configured to deflect the two wavelengths in opposite directions, so that light pulses are transmitted ahead of the field of view of the detector in the scanning direction of the lidar system. A controller may determine the scanning direction of a scanner in the lidar system and transmit a control signal to a light source indicative of a wavelength that corresponds to the scanning direction. The light source may then transmit light pulses at the requested wavelength.

Abstract: A lidar system with improved signal-to-noise ratio in the presence of solar background noise. The lidar system can comprise a light source to emit light toward a target. The light source can have an operating wavelength which lies within a band that delineates a relative maximum in atmospheric absorption. The lidar system can also include a detector to detect scattered light from the target and a processor to determine a characteristic of the target based on a characteristic of the scattered light received at the detector.

Abstract: A lidar system with a pulsed laser diode to produce a plurality of optical seed pulses of light at one or more operating wavelengths between approximately 1400 nm and approximately 1600 nm. The lidar system may also include one or more optical amplifiers to amplify the optical seed pulses to produce a plurality of output optical pulses. Each optical amplifier may produce an amount of amplified spontaneous emission (ASE), and the output optical pulses may have characteristics comprising: a pulse repetition frequency of less than or equal to 100 MHz; a pulse duration of less than or equal to 20 nanoseconds; and a duty cycle of less than or equal to 1%. The lidar system may also include one or more optical filters to attenuate the ASE and a receiver to detect at least a portion of the output optical pulses scattered by a target located a distance.

Abstract: A lidar system with a pulsed laser diode to produce a plurality of optical seed pulses of light at one or more operating wavelengths between approximately 1400 nm and approximately 1600 nm. The lidar system may also include one or more optical amplifiers to amplify the optical seed pulses to produce a plurality of output optical pulses. Each optical amplifier may produce an amount of amplified spontaneous emission (ASE), and the output optical pulses may have characteristics comprising: a pulse repetition frequency of less than or equal to 100 MHz; a pulse duration of less than or equal to 20 nanoseconds; and a duty cycle of less than or equal to 1%. The lidar system may also include one or more optical filters to attenuate the ASE and a receiver to detect at least a portion of the output optical pulses scattered by a target located a distance.

Abstract: A lidar system with a light source to emit a pulse of light and a receiver to detect a return pulse of light. The receiver can include a first channel to receive a first portion of the return pulse and produce a first digital output signal, and a second channel to receive a second portion of the return pulse and produce a second digital output signal. The receiver can include a logic circuit to produce an output electrical-edge signal in response to receiving the digital output signals. The receiver can also include a time-to-digital converter to determine a time interval based on an emission time of the pulse of light and based on the electrical-edge signal. The lidar system can also include a processor to determine a distance to a target based at least in part on the time interval.

Abstract: A lidar system with a light source to emit a pulse of light and a receiver to detect a return pulse of light. The receiver can include a first channel to receive a first portion of the return pulse and produce a first digital output signal, and a second channel to receive a second portion of the return pulse and produce a second digital output signal. The receiver can include a logic circuit to produce an output electrical-edge signal in response to receiving the digital output signals. The receiver can also include a time-to-digital converter to determine a time interval based on an emission time of the pulse of light and based on the electrical-edge signal. The lidar system can also include a processor to determine a distance to a target based at least in part on the time interval.

Abstract: In one embodiment, a lidar system includes a self-Raman laser that includes a Raman-active gain medium and a Q-switch. The self-Raman laser is configured to: produce Q-switched pulses of light at a lasing wavelength of the self-Raman laser; Raman-shift, in the Raman-active gain medium, at least a portion of the Q-switched pulses to produce Raman-shifted pulses of light, where the Raman-shifted pulses have a Raman-shifted wavelength that is longer than the lasing wavelength; and emit at least a portion of the Raman-shifted pulses. The lidar system further includes a scanner configured to scan the emitted pulses of light across a field of regard and a receiver configured to detect at least a portion of the scanned pulses of light scattered by a target located a distance from the lidar system. The lidar system also includes a processor configured to determine the distance from the lidar system to the target.

Abstract: A lidar system may have a light source configured to emit pulses of light along a field of view of the light source and a scanner to scan the light source field of view in a scanning direction across a plurality of pixels located downrange from the lidar system. The scanner can direct a pulse of light, which is emitted by the light source along the light source field of view, toward a pixel and can scan a field of view of a first detector. The first detector field of view can be scanned in the scanning direction across the plurality of pixels and the scanning speed of the first detector field of view can be approximately equal to the scanning speed of the light source field of view. The first detector can detect a portion of the pulse of light scattered by a target located at least partially within the pixel.

Abstract: A lidar system with a pulsed laser diode configured to produce an optical seed pulse of light at an operating wavelength between approximately 1400 nm and approximately 1600 nm. The lidar system may also include an optical amplifier configured to amplify the optical seed pulse to produce an eye-safe output optical pulse that is emitted into a field of view. The optical amplifier may produce an amount of amplified spontaneous emission (ASE) associated with the output optical pulse. The lidar system may include an optical filter configured to filter the output optical pulse to reduce the associated ASE. The lidar system may also include a receiver configured to detect at least a portion of the output optical pulse reflected or scattered from the field of view.

Abstract: A lidar system having a light source to emit an output beam and an overlap mirror having a reflecting surface with an aperture through which the output beam passes. The lidar system may include mirrors driven by a galvanometer scanner, a resonant scanner, a microelectromechanical systems device, or a voice coil motor. The mirrors may direct the output beam toward a light source field of view (FOV) and may move the light source FOV to different locations within a field of regard. The mirrors may receive reflected portions of the output beam as an input beam and direct the input beam toward the reflecting surface of the overlap mirror. The lidar system may include a receiver to receive the input beam from the reflecting surface of the overlap mirror. The receiver may have a receiver FOV that moves synchronously with, and at least partially overlaps, the light source FOV.

Abstract: In one embodiment, a system includes a first lidar sensor, which includes a first scanner configured to scan first pulses of light along a first scan pattern and a first receiver configured to detect scattered light from the first pulses of light. The system also includes a second lidar sensor, which includes a second scanner configured to scan second pulses of light along a second scan pattern and a second receiver configured to detect scattered light from the second pulses of light. The first scan pattern and the second scan pattern are at least partially overlapped. The system further includes an enclosure, where the first lidar sensor and the second lidar sensor are contained within the enclosure. The enclosure includes a window configured to transmit the first pulses of light and the second pulses of light.

Abstract: A lidar system with a pulsed laser diode configured to produce an optical seed pulse of light at an operating wavelength between approximately 1400 nm and approximately 1600 nm. The lidar system may also include an optical amplifier configured to amplify the optical seed pulse to produce an eye-safe output optical pulse that is emitted into a field of view. The optical amplifier may produce an amount of amplified spontaneous emission (ASE) associated with the output optical pulse. The lidar system may include an optical filter configured to filter the output optical pulse to reduce the associated ASE. The lidar system may also include a receiver configured to detect at least a portion of the output optical pulse reflected or scattered from the field of view.

Abstract: A lidar system may have a light source configured to emit a pulse of light and a scanner that scans a field of view of the light source in a forward-scanning direction across a plurality of pixels located downrange from the lidar system. The scanner can direct the pulse of light toward the second pixel and scan a field of view of a first detector. The first-detector field of view can be offset from the light-source field of view in a direction opposite the forward-scanning direction. When the pulse is emitted, the first-detector field of view can at least partially overlap the first pixel and the light-source field of view can at least partially overlap the second pixel. The first detector can be configured to detect a portion of the pulse of light scattered by a target located at least partially within the second pixel.