LIDAR SYSTEM WITH DISTRIBUTED LASER AND MULTIPLE SENSOR HEADS

• US 20170153319A1
• Filed: 11/29/2016
• Published: 06/01/2017
• Est. Priority Date: 11/30/2015
• Status: Active Grant

• Current Assignee: Luminar Technologies, Inc.
• Original Assignee: Luminar Technologies, Inc.
• Inventors: Eichenholz, Jason M., Villeneuve, Alain
• Granted Patent: US 10,591,600 B2
• Time in Patent Office: Days
• CPC Class Codes: G01S 17/00 Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
• CPC Class Codes: G01S 17/02 Systems using the reflection of electromagnetic waves other than radio waves G01S17/66 takes precedence
• CPC Class Codes: G01S 17/06 Systems determining position data of a target
• CPC Class Codes: G01S 17/08 for measuring distance only indirect measurement G01S17/46; active triangulation systems G01S17/48
• CPC Class Codes: G01S 17/10 using transmission of interrupted, pulse-modulated waves determination of distance by phase measurements G01S17/32
• CPC Class Codes: G01S 17/14 wherein a voltage or current pulse is initiated and terminated in accordance with the pulse transmission and echo reception respectively, e.g. using counters
• CPC Class Codes: G01S 17/26 wherein the transmitted pulses use a frequency-modulated or phase-modulated carrier wave, e.g. for pulse compression of received signals
• CPC Class Codes: G01S 17/32 using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated
• CPC Class Codes: G01S 17/42 Simultaneous measurement of distance and other co-ordinates indirect measurement G01S17/46
• CPC Class Codes: G01S 17/88 Lidar systems specially adapted for specific applications
• CPC Class Codes: G01S 17/89 for mapping or imaging
• CPC Class Codes: G01S 17/931 of land vehicles
• CPC Class Codes: G01S 7/4804 Auxiliary means for detecting or identifying lidar signals or the like, e.g. laser illuminators
• CPC Class Codes: G01S 7/4811 common to transmitter and receiver
• CPC Class Codes: G01S 7/4814 of transmitters alone
• CPC Class Codes: G01S 7/4815 using multiple transmitters
• CPC Class Codes: G01S 7/4816 of receivers alone
• CPC Class Codes: G01S 7/4817 relating to scanning
• CPC Class Codes: G01S 7/4818 using optical fibres
• CPC Class Codes: G01S 7/483 Details of pulse systems
• CPC Class Codes: G01S 7/484 : Transmitters
• CPC Class Codes: G01S 7/4861 : Circuits for detection, sampling, integration or read-out
• CPC Class Codes: G01S 7/4863 : Detector arrays, e.g. charge-transfer gates
• CPC Class Codes: G01S 7/4865 : Time delay measurement, e.g. time-of-flight measurement, time of arrival measurement or determining the exact position of a peak peak detection in noise, signal conditioning G01S7/487
• CPC Class Codes: G01S 7/4873 : by deriving and controlling a threshold value
• CPC Class Codes: G01S 7/4876 : by removing unwanted signals G01S7/495 takes precedence
• CPC Class Codes: H01S 2301/02 : ASE (amplified spontaneous emission), noise; Reduction thereof
• CPC Class Codes: H01S 3/0007 : Applications not otherwise provided for working metals or other materials by laser beam B23K26/00; using photons to produce a reactive propulsive thrust F03H3/00; optical recording of measured values in general G01D15/14; optics in general G02B; holographic processes or apparatus G03H; optical marking or sensing of data record carriers G06K7/10 - G06K7/14, G06K15/12; injection heating of plasma by laser H05H1/22; acceleration of neutral particles by electromagnetic wave pressure H05H3/04
• CPC Class Codes: H01S 3/0078 : Frequency filtering
• CPC Class Codes: H01S 3/0085 : Modulating the output, i.e. the laser beam is modulated outside the laser cavity
• CPC Class Codes: H01S 3/06733 : Fibre having more than one cladding
• CPC Class Codes: H01S 3/0675 : Resonators including a grating structure, e.g. distributed Bragg reflectors [DBR] or distributed feedback [DFB] fibre lasers
• CPC Class Codes: H01S 3/06754 : Fibre amplifiers H01S3/06708 takes precedence
• CPC Class Codes: H01S 3/06758 : Tandem amplifiers
• CPC Class Codes: H01S 3/08086 : Multiple-wavelength emission
• CPC Class Codes: H01S 3/094003 : the pumped medium being a fibre
• CPC Class Codes: H01S 3/094042 : of a fibre laser
• CPC Class Codes: H01S 3/094076 : Pulsed or modulated pumping H01S3/1024 takes precedence
• CPC Class Codes: H01S 3/0941 : of a laser diode
• CPC Class Codes: H01S 3/10023 : by functional association of additional optical elements, e.g. filters, gratings, reflectors
• CPC Class Codes: H01S 3/1106 : Mode locking
• CPC Class Codes: H01S 3/1608 : erbium
• CPC Class Codes: H01S 3/2383 : Parallel arrangements
• CPC Class Codes: H01S 5/0057 : for temporal shaping, e.g. pulse compression, frequency chirping
• CPC Class Codes: H01S 5/0085 : for modulating the output, i.e. the laser beam is modulated outside the laser cavity
• CPC Class Codes: H01S 5/4012 : Beam combining, e.g. by the use of fibres, gratings, polarisers, prisms
• CPC Class Codes: H01S 5/4087 : emitting more than one wavelength

Abstract

In one embodiment, a lidar system includes a light source configured to emit pulses of light. The lidar system also includes multiple optical links and multiple sensor heads. Each optical link couples the light source to a corresponding sensor head, and each optical link is configured to convey at least a portion of the emitted pulses of light from the light source to the corresponding sensor head. Each sensor head includes a scanner configured to scan pulses of light across a field of regard of the sensor head, where the scanned pulses of light include the portion of the emitted pulses of light conveyed from the light source to the sensor head by the corresponding optical link. Each sensor head also includes a receiver configured to detect at least a portion of the scanned pulses of light scattered or reflected by a target located downrange from the sensor head.

Claims

1. A lidar system comprising:

a light source configured to emit pulses of light;

a plurality of optical links, wherein each optical link couples the light source to a corresponding sensor head of a plurality of sensor heads, wherein the optical link is configured to convey at least a portion of the emitted pulses of light from the light source to the corresponding sensor head; and

the plurality of sensor heads, wherein each sensor head comprises;

a scanner configured to scan pulses of light across a field of regard of the sensor head, wherein the scanned pulses of light comprise the portion of the emitted pulses of light conveyed from the light source to the sensor head by the corresponding optical link; and

a receiver configured to detect at least a portion of the scanned pulses of light scattered or reflected by a target located downrange from the sensor head.

2. The lidar system of claim 1, wherein:

the target is at least partially contained within the field of regard of the sensor head and is located a distance from the sensor head that is less than or equal to a maximum range of the lidar system; and

the sensor head further comprises a processor configured to determine the distance from the sensor head to the target based at least in part on a time of flight for a pulse of light to travel from the sensor head to the target and back to the sensor head.

3. The lidar system of claim 1, wherein the lidar system is incorporated into a vehicle wherein the sensor heads are positioned to provide a 360-degree view of an environment around the vehicle.

4. The lidar system of claim 1, wherein each optical link comprises a fiber-optic cable having a length greater than or equal to 1 meter.

5. The lidar system of claim 1, further comprising a plurality of electrical links corresponding to the plurality of optical links, wherein each electrical link couples the light source to a respective sensor head of the plurality of sensor heads, wherein the electrical link is configured to convey electrical power or one or more electrical signals between the light source and the respective sensor head.

6. The lidar system of claim 1, wherein the light source comprises:

a seed laser configured to produce low-power optical pulses; and

one or more optical amplifiers configured to amplify the low-power optical pulses to produce the pulses of light emitted by the light source.

7. The lidar system of claim 6, wherein the light source further comprises one or more optical filters, wherein each optical filter is configured to reduce an amount of amplified spontaneous emission light produced by one or more of the optical amplifiers.

8. The lidar system of claim 6, wherein the light source further comprises a supplemental light source combined with the seed laser, wherein light from the supplemental light source is configured to prevent at least one of the optical amplifiers from spontaneously emitting an optical pulse during a time after amplification of a first low-power optical pulse and prior to receipt of a second low-power optical pulse.

9. The lidar system of claim 1, wherein the light source comprises:

a plurality of laser diodes, wherein each laser diode is configured to produce light at a different operating wavelength; and

an optical multiplexer configured to combine the light produced by each laser diode into a single optical fiber.

10. The lidar system of claim 1, wherein the light source comprises a wavelength-tunable laser configured to produce optical pulses at a plurality of wavelengths of light corresponding to the plurality of sensor heads, wherein each wavelength produced by the wavelength-tunable laser is conveyed to a corresponding sensor head.

11. The lidar system of claim 1, wherein the light source comprises an optical amplifier comprising one or more optical filters, wherein each optical filter is configured to reduce an amount of amplified spontaneous emission light produced by the optical amplifier.

12. The lidar system of claim 1, wherein:

the lidar system comprises N optical links coupled to N respective sensor heads; and

the light source comprises a 1×

N optical demultiplexer configured to distribute the emitted pulses of light between the N optical links.

13. The lidar system of claim 12, wherein the optical demultiplexer comprises an optical-power splitter, an optical switch, or a wavelength demultiplexer.

14. The lidar system of claim 12, wherein distributing the emitted pulses of light between the N optical links comprises:

splitting each emitted pulse of light into N pulses of light; and

sending each pulse of the N pulses to a corresponding optical link for transmission to a corresponding sensor head.

15. The lidar system of claim 12, wherein:

the pulses of light emitted by the light source comprise pulses having N different wavelengths; and

distributing the emitted pulses of light between the N optical links comprises sending each pulse having a particular wavelength to a corresponding optical link for transmission to a corresponding sensor head.

16. The lidar system of claim 1, wherein each optical link comprises a gain fiber of a fiber-optic amplifier, wherein the gain fiber is configured to amplify the portion of the emitted pulses of light while propagating from the light source to the corresponding sensor head.

17. The lidar system of claim 1, wherein each optical link comprises a gain fiber of an optical amplifier, wherein the gain fiber is distributed along a length of the optical link and is configured to amplify the portion of the emitted pulses of light while the portion of the emitted pulses of light is conveyed from the light source to the corresponding sensor head.

18. The lidar system of claim 1, wherein each sensor head further comprises an optical amplifier configured to:

amplify the pulses of light conveyed to the sensor head by the optical link; and

send the amplified pulses of light to the scanner for scanning across the field of regard of the sensor head.

19. The lidar system of claim 18, wherein the optical amplifier is a free-space amplifier or a fiber-optic amplifier.