Crosstalk reduction for light detection and ranging (lidar) devices using wavelength locking

Patent metadata

Field	Value
Publication number	US-11947048-B2
Application number	US-202017061003-A
Country	US
Kind code	B2
Filing date	Oct 1, 2020
Priority date	May 6, 2020
Publication date	Apr 2, 2024
Grant date	Apr 2, 2024

Abstract

Example embodiments relate to crosstalk reduction for light detection and ranging (lidar) devices using wavelength locking. An example embodiment includes a lidar device. The lidar device includes a first light emitter configured to emit a first light signal and a second light emitter configured to emit a second light signal. The lidar device also includes a first light guide and a second light guide. In addition, the lidar device includes a first light detector and a second light detector. Further, the lidar device includes a first wavelength-locking mechanism configured to use a portion of the first light signal to maintain a wavelength of the first light signal and a second wavelength-locking mechanism configured to use a portion of the second light signal to maintain a wavelength of the second light signal. The wavelengths of the first light signal and the second light signal are different.

First claim

What is claimed is:

1. A light detection and ranging (lidar) device comprising:
a first light emitter configured to emit a first light signal;
a second light emitter configured to emit a second light signal;
a transparent substrate;
a first light guide disposed on the transparent substrate, wherein the first light guide is optically coupled to the first light emitter and configured to guide the first light signal from a first input end to a first output end, wherein the first output end comprises a first angled portion configured to direct the first light signal through the transparent substrate and toward an environment surrounding the lidar device;
a second light guide disposed on the transparent substrate, wherein the second light guide is optically coupled to the second light emitter and configured to guide the second light signal from a second input end to a second output end, wherein the second output end comprises a second angled portion configured to direct the second light signal through the transparent substrate and toward the environment surrounding the lidar device;
a first light detector positioned to receive the first light signal upon the first light signal being reflected by a first object in the environment surrounding the lidar device;
a second light detector positioned to receive the second light signal upon the second light signal being reflected by a second object in the environment surrounding the lidar device;
a first wavelength-locking mechanism configured to use a portion of the first light signal to maintain a wavelength of the first light signal; and
a second wavelength-locking mechanism configured to use a portion of the second light signal to maintain a wavelength of the second light signal, wherein the wavelength of the first light signal and the wavelength of the second light signal are different from one another.

2. The lidar device of claim 1 , further comprising an aperture structure having a first aperture and a second aperture defined therein, wherein the first light detector is positioned to receive the first light signal, wherein the first light signal is reflected by the first object in the environment surrounding the lidar device and travels through the first aperture, wherein the second light detector is positioned to receive the second light signal, and wherein the second light signal is reflected by the second object in the environment surrounding the lidar device and travels through the second aperture.

3. The lidar device of claim 1 , wherein the first wavelength-locking mechanism comprises a first distributed Bragg reflector defined within the first light guide that redirects the portion of the first light signal back toward the first light emitter, and wherein the second wavelength-locking mechanism comprises a second distributed Bragg reflector defined within the second light guide that redirects the portion of the second light signal back toward the second light emitter.

4. The lidar device of claim 3 , wherein the first distributed Bragg reflector defined within the first light guide is positioned closer to the first input end than to the first output end, and wherein the second distributed Bragg reflector defined within the second light guide is poisitioned closer to the second input end than to the second output end.

5. The lidar device of claim 1 , wherein the first wavelength-locking mechanism comprises a first volume Bragg grating that redirects the portion of the first light signal back toward the first light emitter, and wherein the second wavelength-locking mechanism comprises a second volume Bragg grating that redirects the portion of the second light signal back toward the second light emitter.

6. The lidar device of claim 5 , wherein the first volume Bragg grating is optically positioned between the first light emitter and the first light guide, and wherein the second volume Bragg grating is optically positioned between the second light emitter and the second light guide.

7. The lidar device of claim 5 , wherein the first volume Bragg grating is embedded within the transparent substrate, and wherein the second volume Bragg grating is embedded within the transparent substrate.

8. The lidar device of claim 1 , wherein the first wavelength-locking mechanism comprises a first dye or a first quantum-dot material within the first light guide, and wherein the second wavelength-locking mechanism comprises a second dye or a second quantum-dot material within the second light guide.

9. The lidar device of claim 1 , wherein the first wavelength-locking mechanism comprises a first optical filter positioned at the first output end of the first light guide, and wherein the second wavelength-locking mechanism comprises a second optical filter positioned at the second output end of the second light guide.

10. The lidar device of claim 1 , wherein the first wavelength-locking mechanism is a first portion of a chirped volume Bragg grating, and wherein the second wavelength-locking mechanism is a second portion of the chirped volume Bragg grating.

11. The lidar device of claim 1 , wherein the first wavelength-locking mechanism reduces a temperature-dependency of the wavelength of the first light signal, and wherein the second wavelength-locking mechanism reduces a temperature-dependency of the wavelength of the second light signal.

12. A method comprising:
emitting, from a first light emitter of a light detection and ranging (lidar) device, a first light signal;
emitting, from a second light emitter of the lidar device, a second light signal;
guiding, by a first light guide disposed on a transparent substrate and optically coupled to the first light emitter, the first light signal from a first input end to a first output end, wherein the first output end comprises a first angled portion configured to direct the first light signal through the transparent substrate toward an environment surrounding the lidar device;
guiding, by a second light guide disposed on the transparent substrate and optically coupled to the second light emitter, the second light signal from a second input end to a second output end, wherein the second output end comprises a second angled portion configured to direct the second light signal through the transparent substrate and toward the environment surrounding the lidar device;
maintaining, by a first wavelength-locking mechanism using a portion of the first light signal, a wavelength of the first light signal;
maintaining, by a second wavelength-locking mechanism using a portion of the second light signal, a wavelength of the second light signal, wherein the wavelength of the first light signal and the wavelength of the second light signal are different from one another;
receiving, by a first light detector, the first light signal upon the first light signal being reflected by a first object in the environment surrounding the lidar device; and
receiving, by a second light detector, the second light signal upon the second light signal being reflected by a second object in the environment surrounding the lidar device.

13. The method of claim 12 , wherein the first light signal is received by the first light detector upon the first light signal traveling through a first aperture defined within an aperture plate, and wherein the second light signal is received by the second light detector upon the second light signal traveling through a second aperture defined within the aperture plate.

14. The method of claim 12 , wherein the first wavelength-locking mechanism comprises a first distributed Bragg reflector defined within the first light guide, wherein maintaining the wave

Assignees

• Waymo Llc

Inventors

• Schleuning David
• Droz Pierre-Yves
• Watson Jason
• Dunphy James

Classifications

• G01S7/487 Primary

  Extracting wanted echo signals {, e.g. pulse detection} · CPC title

• G01S7/4818

  using optical fibres · CPC title

• G01S7/4863

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

• G01S17/931

  of land vehicles · CPC title

• G01S7/4815 Primary

  using multiple transmitters · CPC title