Highly multiplexed coherent LIDAR system

Patent metadata

Field	Value
Publication number	US-11378689-B2
Application number	US-202016793505-A
Country	US
Kind code	B2
Filing date	Feb 18, 2020
Priority date	Feb 18, 2020
Publication date	Jul 5, 2022
Grant date	Jul 5, 2022

Abstract

A light detection and ranging (LIDAR) system comprises a laser diode; a laser diode driver circuit configured generate a laser beam using the laser diode and to frequency chirp the generated laser beam according to a frequency chirp period; a laser splitter to split the generated laser beam into N transmit laser beams pointed at different angles, wherein N is an integer greater than one, and a frequency chirp period of each of the N transmit laser beams is the frequency chirp period of the generated laser beam; and multiple return beam paths to receive N return beams and determine time of flight values for the N return beams in parallel.

First claim

What is claimed is:

1. A light detection and ranging (LIDAR) system, the system comprising:
a laser diode;
a laser diode driver circuit configured to generate a laser beam using the laser diode and to frequency chirp the generated laser beam according to a frequency chirp period;
a laser splitter configured to split the generated laser beam into N transmit laser beams pointed at different angles and transmit at the same time, wherein N is an integer greater than one, and a frequency chirp period of each of the N transmit laser beams is the frequency chirp period of the generated laser beam; and
multiple return beam paths to receive N return beams and determine time of flight values for the N return beams in parallel.

2. The system of claim 1 , wherein the laser splitter is configured to split the generated laser beam into N transmit laser beams arranged as a two-dimensional grid of N laser beams.

3. The system of claim 2 , including a beam steering mechanism configured to steer the two-dimensional grid of N laser beams to multiple scan positions; and
wherein the multiple return beam paths are configured to receive N return beams for the multiple scan positions.

4. The system of claim 1 , wherein the laser splitter is configured to split the generated laser beam into N transmit laser beams in one dimension as a line of N transmit laser beams.

5. The system of claim 4 , including a beam steering mechanism configured to steer the line of N laser beams to multiple scan positions; and
wherein the multiple return beam paths are configured to receive N return beams for the multiple scan positions.

6. The system of claim 1 ,
wherein the laser splitter is configured to split the generated laser beam into N beam channels that each include a transmit beam path and a return beam path of the multiple return beams paths; and
wherein the frequency chirp period of the laser diode driver circuit is specified according to the number N of beam channels.

7. The system of claim 1 , including:
a photonic integrated circuit (PIC) having N beam channels configured to receive the N transmit laser beams; and
wherein each of the N channels of the PIC includes a return beam path of the multiple return beam paths.

8. The system of claim 1 , including:
an optical fiber configured to receive the generated laser beam;
wherein the laser splitter includes one or more optical fiber splitters configured to split the generated laser beam received on the optical fiber into N transmit laser beams of N beam channels; and
wherein each of the N beam channels includes a photodiode to receive a return beam of the N return beams.

9. The system of claim 1 ,
wherein the laser splitter includes a diffractive optical element configured to split the generated laser beam into the N transmit laser beams;
a photodiode array; and
a lens configured to direct the N return beams onto the photodiode array.

10. The system of claim 1 , wherein each return beam path of the multiple return beam paths includes a photodiode, a trans impedance amplifier, and an analog-to-digital converter (ADC).

11. The system of claim 10 , including processing circuitry configured to calculate one or both of a range and relative radial velocity for each of the N return beams in parallel.

12. A method of operating a light detection and ranging (LIDAR) system, the method comprising:
generating a laser beam and frequency chirping the generated laser beam using a frequency chirp period;
splitting the generated laser beam into N transmit laser beams pointed at multiple different angles and transmitting the N transmit laser beams at the same time, wherein N is an integer greater than one, and a chirp period of each of the N transmit laser beams is the frequency chirp period of the generated laser beam;
receiving N return beams at the LIDAR system; and
determining multiple time of flight values in parallel using the N return beams.

13. The method of claim 12 , wherein splitting the generated laser beam includes splitting the generated laser beam into N transmit laser beams arranged as a two-dimensional grid of N laser beams.

14. The method of claim 13 , including:
beam steering the N transmit laser beams to scan the two-dimensional grid of N laser beams in a field of view; and
wherein receiving N return beams includes receiving N return beams for multiple scan positions of the two-dimensional grid of N laser beams.

15. The method of claim 12 , wherein splitting the generated laser beam includes splitting the generated laser beam into N transmitted laser beams in one dimension as a line of N laser beams.

16. The method of claim 15 , including:
beam steering the N transmitted laser beams to scan the line of N laser beams in a field of view; and
wherein receiving N returned beams includes receiving N returned beams for multiple scan positions of the two-dimensional grid of N laser beams.

17. The method of claim 12 , including:
wherein splitting the generated laser beam includes splitting the generated laser beam into N channels; and
determining the frequency chirp period of the generated laser beam according to the number of channels.

18. The method of claim 12 ,
wherein splitting the generated laser beam includes splitting the generated beams into N channels of a photonic integrated circuit (PIC); and
wherein receiving the N returned beams includes receiving a returned beam at an integrated photodiode of each of the N channels of the PIC.

19. The method of claim 12 ,
wherein generating a laser beam includes coupling the generated laser beam to an optical fiber as a fiber-coupled laser beam;
wherein splitting the generated laser beam includes splitting the fiber-coupled laser beam into N channels using one or more optical fiber splitters; and
wherein receiving the N returned beams includes receiving a returned beam at a photodiode included in each of the N channels.

20. The method of claim 12 ,
wherein splitting the generated laser beam includes splitting the generated laser beam into the N transmitted laser beams using a diffractive optical element; and
applying the N returned beams to a photodiode array of the LIDAR system.

21. The method of claim 12 , including calculating one or both of a range and relative radial velocity for each of the N return beams in parallel.

22. A light detection and ranging (LIDAR) system, the system comprising:
means for generating a laser beam using the laser diode;
means for frequency chirping the generated laser beam according to a frequency chirp period;
means for splitting the generated laser beam into N transmit laser beams pointed at different angles and transmitting the N transmit laser beams at the same time, wherein N is an integer greater than one, and a frequency chirp period of each of the N transmit laser beams is the frequency chirp period of the generated laser beam;
means for receiving N return beams; and
means for determining time of flight values for the N return beams in parallel.

Assignees

• Analog Devices Inc

Inventors

• Dunn Tyler Adam
• Sparks Andrew William
• Ziemkiewicz Michael
• Bennett Miles R

Classifications

• G01S17/34 Primary

  using transmission of continuous, frequency-modulated waves while heterodyning the received signal, or a signal derived therefrom, with a locally-generated signal related to the contemporaneously transmitted signal · CPC title

• G01S17/89

  for mapping or imaging · CPC title

• G01S7/4914

  of detector arrays, e.g. charge-transfer gates · CPC title

• G01S17/931

  of land vehicles · CPC title

• G01S7/4911

  Transmitters · CPC title