The subject matter of this specification can be implemented in, among other things, systems and methods that enable lidar devices capable of detecting and processing multiple optical modes present in a beam reflected from a target object. Different received optical modes can be spatially separated and electronic signals can be generated that are representative of a coherence information contained in various optical modes. Multiple generated electronic signals can be amplified, phase-shifted, mixed, etc., to identify signals, individually or in a combination, that can be used for identification of a range and velocity of the target object with the highest accuracy.

A method to compensate for phase impairments in a light detection and ranging (LIDAR) system includes transmitting a first optical beam towards a target, receiving a second optical beam from the target to produce a received optical beam; and generating a digitally-sampled target signal using a local oscillator (LO) beam, a first photo-detector and the received optical beam. The method also includes generating a digitally-sampled reference signal using a reference beam transmitted through a fiber delay device and a second photo-detector, and estimating one or more phase impairments in the LiDAR system using the digitally-sampled reference signal to produce one or more estimated phase impairments. The method also includes performing a first correction on a first phase impairment introduced into the digitally-sampled target signal by the LO beam; performing a second correction on a second phase impairment introduced into the digitally-sampled target signal by the received optical beam.

In a LIDAR device (100) a laser light source (110) generates first laser light having a first laser frequency which is frequency modulated with a first frequency modulation. A non-linear optical element (120) receives the first laser light and generates therefrom second laser light having a comb-like frequency spectrum with a plurality of second laser frequencies which are each frequency modulated with a second frequency modulation defined by the first frequency modulation. A frequency excursion of the second frequency modulation is smaller than a spacing of the second laser frequencies. A diffractive element (140) spatially separates the second laser light according to the second laser frequencies and directs the spatially separated second laser light towards a ranging region (200), with each of the second laser frequencies being directed towards a corresponding spatially distinct target position in the ranging region (200). A detector (150) receives reflections of the second laser light from the ranging region (200) and measures, by simultaneously detecting a frequency modulation of the reflections for each of the second laser frequencies, a distance and/or a velocity at the target position corresponding to the second laser frequency.

A LIDAR system includes a LIDAR chip configured to combine a LIDAR input signal and a reference signal so as to generate a composite light signal. The LIDAR input signal includes light reflected by an object located off of the LIDAR chip. The reference signal does not include light reflected by the object. The system also includes electronics configured to use the composite light signal to approximate a radial velocity between the LIDAR chip and the object. The radial velocity is approximated from a difference between a first distance and a second distance. The first distance is the distance between the object and the LIDAR chip at a first time. The second distance is the distance between the object and the LIDAR chip at a second time.

A LiDAR system includes an optical subsystem with an optical axis. The optical subsystem includes an optical source to emit an optical beam, a first optical lens to transmit the optical beam, an optical window to reflect a first portion of the optical beam to generate a LO signal, an optical scanner to transmit a second portion of the optical beam to a target to scan the target to generate a target return signal, a second optical lens to transmit the LO signal and the target return signal to a PD, and the PD to mix the target return signal with the LO signal to extract range and velocity information. The LO signal is disposed to be decentered from the optical axis on the second optical lens to increase a percentage of an overlap of the LO signal and the target return signal on a detection plane of the PD.

A LIDAR system has a switch configured to direct a switch signal to one of multiple different alternate waveguides. The switch signal carries multiple different channels. The system also includes one more redirection components that receive multiple different channel output signals. Each of the channel output signals carries a different one of the channels. The one more redirection components are configured to redirect the channel output signals such that a direction that each of the channel output signals travels away from the one more redirection components changes in response to a change in the alternate waveguide which receives the switch signal.

The LIDAR chip includes a utility waveguide that guides an outgoing LIDAR signal to a facet through which the outgoing LIDAR signal exits from the chip. The chip also includes a control branch that removes a portion of the outgoing LIDAR signal from the utility waveguide. The control branch includes a control light sensor that receives a light signal that includes light from the removed portion of the outgoing LIDAR signal. The chip also includes a data branch that removes a second portion of the outgoing LIDAR signal from the utility waveguide. The data branch includes a light-combining component that combines a reference light signal that includes light from the second portion of the outgoing LIDAR signal with a comparative light signal that includes light that was reflected off an object located off of the chip.

A coherent imaging system including a transmitter and a receiver. The transmitter includes a coherent source and a power splitter for splitting the electromagnetic radiation into a reference and a signal beam. The receiver includes an image forming device and an array of pixels. Each of the pixels include means for collecting at least a portion of the signal beam imaged on the pixel by an image forming device, as a collected signal; means for splitting the collected signal into a plurality of collected signals each having different phase shifts; means for mixing each of the collected signals with the reference beam so as to form a plurality of mixed signals; and means for detecting the mixed signals and outputting a plurality of output electrical signals in response to the mixed signals.

A light detection and ranging (LIDAR) system performs a method including generating a frequency domain waveform based on a baseband electrical signal in a time domain, wherein the frequency domain waveform includes a spectrum of frequencies and determining a likelihood metric for the spectrum of frequencies of the frequency domain waveform. The method further includes in response to one or more parameters associated with the frequency domain waveform satisfying a condition, modifying the likelihood metric for the spectrum of frequencies based on the one or more parameters associated with the frequency domain waveform to generate a modified likelihood metric for the spectrum of frequencies, selecting a peak frequency from the frequency domain waveform corresponding to a frequency with the highest value for the modified likelihood metric, and determining one or more properties of a target based at least in part on the selected peak frequency.

A laser interferometer that includes a light source configured to emit laser light, an optical divider configured to divide the laser light into a first optical path and a second optical path, an optical modulator being provided on the first optical path or the second optical path, including an oscillator that oscillates when a current is applied, and being configured to modulate the laser light by using the oscillator, a photoreceptor configured to receive the laser light and output a photoreception signal, the laser light being reflected by an object to be measured that is provided on the first optical path or the second optical path, and a demodulation circuit configured to demodulate, from the photoreception signal, a Doppler signal derived from the object to be measured, based on a reference signal and a modulation signal derived from the optical modulator, wherein Iq/f≤1×10.sup.−7 is satisfied, where an amplitude value of the current applied to the oscillator that is oscillating is Iq [A] and an oscillation frequency of the oscillator is f [Hz].