US 11,940,565 B2
Coherent pulsed lidar system
Joseph G. LaChapelle, Philomath, OR (US); Jason M. Eichenholz, Orlando, FL (US); and Alex Michael Sincore, Orlando, FL (US)
Assigned to Luminar Technologies, Inc., Orlando, FL (US)
Filed by Luminar Technologies, Inc., Orlando, FL (US)
Filed on Feb. 19, 2020, as Appl. No. 16/794,500.
Claims priority of provisional application 62/902,479, filed on Sep. 19, 2019.
Claims priority of provisional application 62/889,192, filed on Aug. 20, 2019.
Prior Publication US 2021/0055390 A1, Feb. 25, 2021
Int. Cl. G01S 7/4865 (2020.01); G01S 7/481 (2006.01); G01S 7/484 (2006.01); G01S 7/497 (2006.01); G01S 17/02 (2020.01); G01S 17/10 (2020.01); G01S 17/89 (2020.01)
CPC G01S 7/4865 (2013.01) [G01S 7/4814 (2013.01); G01S 7/4818 (2013.01); G01S 7/484 (2013.01); G01S 17/10 (2013.01); G01S 17/89 (2013.01); G01S 7/4816 (2013.01); G01S 7/4817 (2013.01); G01S 7/497 (2013.01); G01S 17/02 (2013.01)] 33 Claims
OG exemplary drawing
 
1. A lidar system comprising:
a light source configured to emit (i) local-oscillator light and (ii) pulses of light, wherein each emitted pulse of light is coherent with a corresponding portion of the local-oscillator light, and the light source comprises:
a local-oscillator laser diode configured to produce the local-oscillator light, wherein the local-oscillator light comprises continuous-wave light;
a seed laser diode configured to produce seed light, wherein the seed light comprises continuous-wave light; and
a pulsed optical amplifier configured to amplify a temporal portion of the seed light to produce an emitted pulse of light of the emitted pulses of light;
a receiver configured to detect the local-oscillator light and a received pulse of light, the received pulse of light comprising light from the emitted pulse of light that is scattered by a target located a distance from the lidar system, wherein:
the local-oscillator light and the received pulse of light are coherently mixed together at the receiver; and
the receiver comprises:
an optical polarization element configured to alter a polarization of the local-oscillator light to allow the local-oscillator light and the received pulse of light to be coherently mixed together;
a detector configured to produce a photocurrent signal corresponding to the coherent mixing of the local-oscillator light and the received pulse of light; and
a pulse-detection circuit configured to determine, based at least in part on the photocurrent signal, a time-of-arrival for the received pulse of light; and
a processor configured to determine the distance to the target based at least in part on the time-of-arrival for the received pulse of light.