LIDAR sensor system including a dual-polarization transmit and receive optical antenna
A light detection and ranging (LIDAR) sensor system includes a dual-polarization optical antenna, a single-polarization optical antenna, a first receiver, and a second receiver. The dual-polarization optical antenna is configured to (i) emit a transmit beam with a first polarization orientation and (ii) and detect a return beam having a second polarization orientation. The single-polarization optical antenna is configured to detect the return beam having the second polarization orientation.
1. A light detection and ranging (LIDAR) system for a vehicle, the LIDAR system comprising:
one or more LIDAR pixels, wherein at least one of the one or more LIDAR pixels includes:
a first optical antenna configured to emit a transmit beam having a first polarization orientation;
a second optical antenna that is offset from the first optical antenna by a particular distance, wherein the second optical antenna is configured to detect a return beam having a second polarization orientation; and
one or more receivers configured to generate one or more signals in response to detecting the second polarization orientation of the return beam.
2. The LIDAR system of claim 1 , wherein the particular distance is determined to compensate for a beam walk-off of the return beam.
3. The LIDAR system of claim 1 , further comprising:
a rotating mirror configured to direct the transmit beam into an environment in which the vehicle is located and configured to direct the return beam onto the at least one of the one or more LIDAR pixels.
4. The LIDAR system of claim 3 , further comprising:
a birefringent slab positioned between the rotating mirror and the at least one of the one or more LIDAR pixels, wherein the birefringent slab is configured to direct the return beam having the second polarization orientation onto the first optical antenna or the second optical antenna based on a time difference in a rotation of the rotating mirror.
5. The LIDAR system of claim 4 , further comprising:
a lens positioned between the birefringent slab and the rotating mirror, wherein the lens is configured to collimate the transmit beam and direct the transmit beam to the rotating mirror.
6. The LIDAR system of claim 1 , wherein the first optical antenna comprises a dual-polarization optical antenna configured to: (i) emit the transmit beam having the first polarization orientation, and (ii) detect the return beam having the second polarization orientation.
7. The LIDAR system of claim 1 , wherein the second optical antenna comprises a single-polarization optical antenna that is configured to detect the return beam having the second polarization orientation.
8. The LIDAR system of claim 1 , wherein the one or more receivers comprise:
a first receiver configured to generate a first electrical signal in response to the first optical antenna and in response to a first local oscillator signal; and
a second receiver configured to generate a second electrical signal in response to the second optical antenna and in response to a second local oscillator signal.
9. The LIDAR system of claim 8 , wherein the first optical antenna includes a two-dimensional (2D) polarization splitting grating coupler having a first port and a second port, wherein the 2D polarization splitting grating coupler is configured to receive a transmit signal on the first port and is configured to provide the return beam having the second polarization orientation to the second port coupled to at least one receiver of the one or more receivers.
10. The LIDAR system of claim 8 , wherein the second optical antenna comprises a single-polarization optical antenna coupled to the one or more receivers to provide the second polarization orientation of the return beam to the one or more receivers.
11. The LIDAR system of claim 10 , wherein the single-polarization optical antenna includes a one-dimensional (1D) polarization grating coupler.
12. An autonomous vehicle (AV) control system comprising:
a light detection and ranging (LIDAR) system comprising:
one or more LIDAR pixels, wherein at least one of the one or more LIDAR pixels includes:
a first optical antenna configured to emit a transmit beam having a first polarization orientation;
a second optical antenna that is offset from the first optical antenna by a particular distance, wherein the second optical antenna is configured to detect a return beam having a second polarization orientation; and
one or more receivers configured to generate one or more signals in response to detecting the second polarization orientation of the return beam.
13. The AV control system of claim 12 , wherein the particular distance is determined to compensate for a beam walk-off of the return beam.
14. The AV control system of claim 12 , the LIDAR system further comprising:
a rotating mirror configured to direct the transmit beam into an environment in which an autonomous vehicle is located and configured to direct the return beam onto the at least one of the one or more LIDAR pixels.
15. The AV control system of claim 14 , the LIDAR system further comprising:
a birefringent slab positioned between the rotating mirror and the at least one of the one or more LIDAR pixels, wherein the birefringent slab is configured to direct the return beam having the second polarization orientation onto the first optical antenna or the second optical antenna based on a time difference in a rotation of the rotating mirror.
16. The AV control system of claim 15 , the LIDAR system further comprising:
a lens positioned between the birefringent slab and the rotating mirror, wherein the lens is configured to collimate the transmit beam and direct the transmit beam to the rotating mirror.
17. An autonomous vehicle comprising:
a light detection and ranging (LIDAR) system comprising:
one or more LIDAR pixels, wherein at least one of the one or more LIDAR pixels includes:
a first optical antenna configured to emit a transmit beam having a first polarization orientation;
a second optical antenna that is offset from the first optical antenna by a particular distance, wherein the second optical antenna is configured to detect a return beam having a second polarization orientation; and
one or more receivers configured to generate one or more signals in response to detecting the second polarization orientation of the return beam.
18. The autonomous vehicle of claim 17 , wherein the particular distance is determined to compensate for a beam walk-off of the return beam.
19. The autonomous vehicle of claim 17 , the LIDAR system further comprising a rotating mirror configured to direct the transmit beam into an environment in which the autonomous vehicle is located and configured to direct the return beam onto the at least one of the one or more LIDAR pixels.
20. The autonomous vehicle of claim 19 , the LIDAR system further comprising a birefringent slab positioned between the rotating mirror and the at least one of the one or more LIDAR pixels, wherein the birefringent slab is configured to direct the return beam having the second polarization orientation onto the first optical antenna or the second optical antenna based on a time difference in a rotation of the rotating mirror.