Determining characteristics of a target using polarization encoded coherent lidar

Patent metadata

Field	Value
Publication number	US-2021181309-A1
Application number	US-201916712749-A
Country	US
Kind code	A1
Filing date	Dec 12, 2019
Priority date	Dec 12, 2019
Publication date	Jun 17, 2021
Grant date	—

Abstract

A method of operating a light detection and ranging (LIDAR) system is provided that includes generating a beam of co-propagating, cross-polarized light using a first polarizing beam splitter; and determining a material characteristic or orientation of a target using the co-propagating, cross-polarized light.

First claim

What is claimed is:

1 . A method of operating a light detection and ranging (LIDAR) system comprising:
generating a beam of co-propagating, cross-polarized light using a first polarizing beam splitter; and determining at least one of a material characteristic or orientation of a target using the co-propagating, cross-polarized light.

2 . The method of claim 1 , further comprising:
splitting internally reflected light and light reflected from the target into a first output directed to a first detector and a second output directed to a second detector.

3 . The method of claim 1 , further comprising:
splitting light reflected from the target into a first output directed to a first detector and a second output directed to a second detector using a second polarizing beam splitter; and determining a reflectivity and/or orientation of the target based on a comparison of a signal-to-noise ratio between signals from the first detector and the second detector.

4 . The method of claim 3 , further comprising:
splitting the co-propagating, cross-polarized light into a local oscillator path and a target path using a first beam splitter; receiving the local oscillator path light at a third polarizing beam splitter; transmitting the target path light to the target and directing light reflected from the target to the second polarizing beam splitter using an optical path discriminator; mixing the transmitted output of the third polarizing beam splitter and the transmitted output of the second polarizing beam splitter using a first light mixer; mixing the reflected output of the third polarizing beam splitter and the reflected output of the second polarizing beam splitter using a second light mixer; receiving combined light from the first light mixer at the first detector; and receiving combined light from the second light mixer at the second detector.

5 . The method of claim 4 , further comprising: biasing light to the first and second detectors in favor of light from the target path using the first and second light mixers.

6 . The method of claim 4 , further comprising: receiving light from a plurality of laser sources at the first polarizing beam splitter.

7 . The method of claim 6 , further comprising:
receiving a transmitted output from the second polarizing beam splitter and a reflected output from the third polarizing beam splitter at the first light mixer; and receiving a reflected output from the second polarizing beam splitter and a transmitted output from the third polarizing beam splitter at the second light mixer.

8 . The method of claim 6 , further comprising: transmitting light having different frequency patterns using the plurality of laser sources.

9 . The method of claim 4 , further comprising:
combining a first pair of light inputs having dissimilar wavelengths and opposite polarizations using a first wavelength division multiplexer (WDM); combining a second pair of light inputs having dissimilar wavelengths and opposite polarizations using a second WDM; receiving combined light from the first WDM and the second WDM at the first polarizing beam splitter; and separating the combined light from the first light mixer and the second light mixer by wavelength before directing the light to the first detector and the second detector.

10 . The method of claim 4 , further comprising:
receiving light at the first polarizing beam splitter from a second beam splitter operatively coupled to a single laser source; receiving reflected outputs from the second and third polarizing beam splitters at the first light mixer; and receiving transmitted outputs from the second and third polarizing beam splitters at the second light mixer.

11 . A light detection and ranging (LIDAR) apparatus comprising:
a first polarizing beam splitter configured to receive light at a first light input and a second light input and transmit co-propagating, cross-polarized light to a target; a second polarizing beam splitter configured to split light reflected from the target into a transmitted output directed to a first detector and a transmitted output directed to a second detector; and a processing device configured to determine at least one of a material characteristic or an orientation of the target based on a comparison of a signal-to-noise ratio between signals from the first detector and the second detector.

12 . The apparatus of claim 11 , further comprising: the first detector and the second detector configured to transmit signals to the processing device.

13 . The apparatus of claim 11 , further comprising:
a first beam splitter configured to split the co-propagating, cross-polarized light into a local oscillator path and a target path; a third polarizing beam splitter configured to receive the local oscillator path light; an optical path discriminator configured to transmit the target path light to a target and direct light reflected from the target to the second polarizing beam splitter; a first light mixer configured to mix light from the transmitted output of the second polarizing beam splitter and a reflected output of the third polarizing beam splitter; and a second light mixer configured to mix light from the reflected output of the second polarizing beam splitter and a transmitted output of the third polarizing beam splitter, wherein the first detector is configured to receive combined light from the first light mixer and the second detector is configured to receive combined light from the second light mixer.

14 . The apparatus of claim 13 , wherein the first and second light mixers are configured to bias light to the first and second detectors in favor of light from the target path.

15 . The apparatus of claim 13 , wherein the first light input and the second light input are configured to receive light from a plurality of light sources.

16 . The apparatus of claim 15 , wherein the plurality of light sources is configured to transmit light having different frequency patterns.

17 . The apparatus of claim 15 , further comprising a wavelength division multiplexer (WDM) configured to combine light from the first laser source and the second laser source when they have dissimilar wavelengths.

18 . The apparatus of claim 13 , wherein the first and second light inputs are configured to receive light from a second beam splitter operatively coupled to a single laser source.

19 . The apparatus of claim 18 , wherein the first light mixer is configured to receive reflected outputs from the second and third polarizing beam splitters, and the second light mixer is configured to receive transmitted outputs from the second and third polarizing beam splitters.

20 . The apparatus of claim 13 , further comprising:
a second beam splitter configured to split the co-propagating, cross-polarized light into a second local oscillator path; a third beam splitter configured to split a portion of the target path into a second target path; a fourth polarizing beam splitter configured to receive the local oscillator path light; a second optical path discriminator configured to transmit the second target path light to the target and direct light reflected from the target to a fifth polarizing beam splitter, the fifth polarizing beam splitter configured to split light reflected from the target into a transmitted output directed to a third detector and a transmitted output directed to a fourth detector; a third light mixer configured to mix light from the transmitted output of the fifth p

Assignees

• Aeva Inc

Inventors

• Oza Neal N
• Kocaoglu Omer P
• Behzadi Behsan
• Avci Oguzhan
• Gagne Keith
• Rezk Mina

Classifications

• G02B27/1006

  for splitting or combining different wavelengths (G02B27/1086, G02B27/141 take precedence) · CPC title

• G01S7/4817

  relating to scanning · CPC title

• G01S17/58

  Velocity or trajectory determination systems; Sense-of-movement determination systems · CPC title

• G02B27/283

  used for beam splitting or combining · CPC title

• G01S7/4812

  transmitted and received beams following a coaxial path · CPC title