Systems and methods for improving Lidar performance

Patent metadata

Field	Value
Publication number	US-10901074-B1
Application number	US-202016840117-A
Country	US
Kind code	B1
Filing date	Apr 3, 2020
Priority date	Feb 17, 2020
Publication date	Jan 26, 2021
Grant date	Jan 26, 2021

Abstract

Methods and systems for providing eye-safe compatible receiver for a light detection and ranging system. The light detection and ranging system comprises; an emitting unit comprising a light source configured to emit a sequence of light pulses of a first wavelength into a three-dimensional environment; and a receiving module comprising a detector for detecting light pulses of a second wavelength, in which the second wavelength is shorter than the first wavelength, the receiving module further comprising a wavelength converter coupled to the detector and configured to convert an echo signal of the emitted light pulses into the light pulses of the second wavelength.

First claim

What is claimed is:

1. A light detection and ranging system comprising:
an emitting unit comprising a light source configured to emit a sequence of light pulses of a first set of first wavelengths into a three-dimensional environment; and
a receiving module comprising,
(i) a plurality of detectors for detecting light pulses of a second set of second wavelengths, wherein the second set of second wavelengths is shorter than the first set of first wavelengths,
(ii) a wavelength converter configured to convert an echo signal of the emitted light pulses of the first set of first wavelengths into the light pulses of the second set of second wavelengths, wherein an input end of the wavelength converter is configured to receive (a) a mixed signal of the echo signal of the first set of first wavelengths and (b) a pump light comprising multiple wavelengths corresponding to the first set of first wavelengths, and wherein an output end of the wavelength converter is coupled to the plurality of detectors via multiple trains of optical components, respectively, to separate the light pulses of the second set of second wavelengths; and
(iii) one or more optical elements configured to: (a) combine the echo signal of the emitted light pulses of the first set of first wavelengths into the mixed signal, and (b) provide a combination of the mixed signal and the pump light to the input end of the wavelength converter.

2. The light detection and ranging system of claim 1 , wherein the first set of first wavelengths is in a range between 1400 nm and 2050 nm.

3. The light detection and ranging system of claim 1 , wherein the first set of first wavelengths is outside the wavelength range detectable by the detector.

4. The light detection and ranging system of claim 1 , wherein the light source comprises an eye-safe laser and a fiber amplifier.

5. The light detection and ranging system of claim 1 , wherein the emitting unit comprises a scanner to direct the sequence of light pulses to the three-dimensional environment to generate a point distribution pattern.

6. The light detection and ranging system of claim 1 , wherein the plurality of detectors comprise a silicon photomultipliers (SiPM) sensor.

7. The light detection and ranging system of claim 1 , wherein the second set of second wavelength is shorter than 1000 nm.

8. The light detection and ranging system of claim 1 , wherein the second set of second wavelength is within a wavelength range detectable by the detector.

9. The light detection and ranging system of claim 1 , wherein the receiving module comprises a first filter to remove unwanted light from the echo signal having the first set of first wavelengths and a second filter to remove unwanted light from the light pulses of the second set of second wavelengths.

10. The light detection and ranging system of claim 1 , wherein the emitting unit comprises a splitter to split the sequence of light pulses for use in multiple channels.

11. The light detection and ranging system of claim 1 , wherein the light pulses received by the plurality of detectors have the same second wavelength across the multiple channels.

12. The light detection and ranging system of claim 1 , wherein the light pulses received by the plurality of detectors have different wavelengths across the multiple channels.

13. The light detection and ranging system of claim 1 , wherein the sequence of light pulses of the first set of first wavelengths are used by multiple channels.

14. The light detection and ranging system of claim 13 , further comprising one or more processors configured to calculate a distance based on a time of flight associated with the light pulses for the multiple channels.

15. The light detection and ranging system of claim 1 , wherein the wavelength converter comprises periodical poled lithium niobate (PPLN) crystal and a pump laser.

16. The light detection and ranging system of claim 15 , wherein the pump light produced by the pump laser and the echo signal of the emitted light pulses are received at the PPLN and converted into the light pulses of the second set of second wavelengths.

17. The light detection and ranging system of claim 16 , wherein the second set of second wavelength is based on the wavelengths of the pump light and the first set of first wavelengths.

18. A method for a light detection and ranging system comprising:
emitting a sequence of light pulses of a first set of first wavelengths into a three-dimensional environment;
combining, by one or more optical elements, an echo signal of the emitted light pulses of the first set of first wavelengths into a mixed signal and providing a combination of the mixed signal and a pump light to an input end of a wavelength converter, wherein the pump light comprises multiple wavelengths corresponding to the first set of first wavelengths,
converting, by the wavelength converter, the echo signal of the emitted light pulses into light pulses of a second set of second wavelengths, wherein the input end of the wavelength converter receives the combination of the mixed signal of the echo signal and the pump light, and wherein an output end of the wavelengths converter is coupled to a plurality of detectors via multiple trains of optical components, respectively, to separate the light pulses of the second set of second wavelengths; and
receiving, at the plurality of detectors, the light pulses of the second set of second wavelengths, wherein the second set of second wavelengths is shorter than the first set of first wavelengths.

19. The method of claim 18 , wherein the first set of first wavelengths is in a range between 1400 nm and 2050 nm or is outside the wavelength range detectable by the plurality of detectors.

20. The method of claim 18 , wherein the sequence of light pulses generated by a light source comprising an eye-safe laser and a fiber amplifier.

21. The method of claim 18 , wherein the sequence of light pulses are directed to the three-dimensional environment by a scanner to generate a point distribution pattern.

22. The method of claim 18 , wherein the plurality of detectors comprise a silicon photomultipliers (SiPM) sensor.

23. The method of claim 18 , wherein the second set of second wavelength is shorter than 1000 nm or is within a wavelength range detectable by the detector.

24. The method of claim 18 , further comprising removing unwanted light from the echo signal having the first set of first wavelengths and removing unwanted light from the light pulses of the second set of second wavelengths using a second filter.

25. The method of claim 18 , further comprising splitting the sequence of light pulses for use in multiple channels.

Assignees

• Hesai Technology Co Ltd

Inventors

• Pan Zhengqing
• Wu Shixiang
• Xiang Shaoqing
• Sun Kai

Classifications

• G02F1/353

  Frequency conversion, i.e. wherein a light beam is generated with frequency components different from those of the incident light beams · CPC title

• G01S17/93

  for anti-collision purposes · CPC title

• G01S7/4818

  using optical fibres · CPC title

• G01S7/4812

  transmitted and received beams following a coaxial path · CPC title

• G01S7/4814 Primary

  of transmitters alone · CPC title