Lidar system with distributed laser and multiple sensor heads

• US 9,804,264 B2
• Filed: 03/27/2017
• Issued: 10/31/2017
• Est. Priority Date: 11/30/2015
• Status: Active Grant

• Current Assignee: Luminar Technologies, Inc.
• Original Assignee: Luminar Technologies, Inc.
• Inventors: Villeneuve, Alain, Eichenholz, Jason M.
• Primary Examiner(s): Ratcliffe, Luke D
• Application Number:
  US15/470,730
• Publication Number:
  US 20170199277A1
• Time in Patent Office: 218 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

A lidar system which includes one or more light sources to produce one or more optical signals and a demultiplexer to separate the one or more optical signals into a plurality of sub-portions which may be distributed to a plurality of sensor heads. The sensor heads emit the sub-portions of the one or more optical signals into a plurality of fields of view and to detect reflected or scattered light from the fields of view. The lidar system also includes one or more optical amplifiers and one or more filters to reduce amplified spontaneous emission produced by the one or more optical amplifiers.

Claims

1. A lidar system comprising:

one or more light sources configured to produce one or more optical signals;

a demultiplexer configured to separate the one or more optical signals into a plurality of sub-portions and to distribute the plurality of sub-portions of the one or more optical signals via a plurality of optical links, wherein;

the one or more optical signals comprise a plurality of pulses; and

the plurality of sub-portions of the one or more optical signals comprise sub-portions of each of the plurality of pulses, wherein the sub-portions of each of the plurality of pulses are unequal;

a plurality of sensor heads configured to respectively receive the plurality of sub-portions of the one or more optical signals via the plurality of optical links, the plurality of sensor heads further being configured to emit the plurality of sub-portions of the one or more optical signals into a plurality of fields of view and to detect reflected or scattered light from the plurality of fields of view;

one or more optical amplifiers configured to amplify the one or more optical signals or the plurality of sub-portions of the one or more optical signals; and

one or more filters configured to reduce amplified spontaneous emission produced by the one or more optical amplifiers.

2. The lidar system of claim 1, wherein the plurality of sensor heads respectively comprise a plurality of scanners, each of the plurality of scanners being configured to scan at least one of the sub-portions of the one or more optical signals within a corresponding field of regard that includes at least one of the plurality of fields of view.

3. The lidar system of claim 1, wherein the plurality of sensor heads respectively comprise a plurality of receivers to detect the reflected or scattered light.

4. The lidar system of claim 1, wherein the plurality of sensor heads respectively comprise a plurality of processors, each of the plurality of processors being configured to determine a distance to a target based on at least a portion of the reflected or scattered light.

5. The lidar system of claim 4, wherein each of the plurality of processors is configured to determine the distance to the target based at least in part on a roundtrip time of flight for a pulse of light traveling between the sensor head and the target.

6. The lidar system of claim 1, wherein the lidar system is incorporated into a vehicle.

7. The lidar system of claim 6, wherein the sensor heads are positioned about the vehicle to provide at least a 180-degree view of an environment around the vehicle.

8. The lidar system of claim 1, further comprising the plurality of optical links.

9. The lidar system of claim 8, where at least one of the optical links comprises a fiber-optic cable having a length greater than or equal to 1 meter.

10. The lidar system of claim 8, further comprising a plurality of electrical links respectively corresponding to the plurality of optical links, the plurality of electrical links being configured to convey electrical signals to the plurality of sensor heads.

11. The lidar system of claim 1, wherein the one or more light sources comprise one or more seed lasers configured to produce the one or more optical signals.

12. The lidar system of claim 11, wherein:

the plurality of pulses comprises a first pulse and a second pulse; and

the one or more light sources further comprise one or more supplemental light sources whose light is combined with that of the one or more seed lasers prior to amplification in order to reduce the likelihood of at least one of the one or more optical amplifiers spontaneously emitting amplified light during a time between the first pulse and the second pulse.

13. The lidar system of claim 1, wherein the one or more light sources are configured to produce light at a plurality of different operating wavelengths.

14. The lidar system of claim 1, further comprising an optical multiplexer configured to combine a plurality of the one or more optical signals from a plurality of the one or more light sources into a single optical fiber.

15. The lidar system of claim 14, wherein the output of the optical multiplexer is provided to the one or more optical amplifiers to amplify the plurality of the one or more optical signals.

16. The lidar system of claim 1, wherein the plurality of sub-portions of the one or more optical signals comprise a plurality of wavelengths of light, and wherein the plurality of sub-portions of the one or more optical signals are respectively distributed to the plurality of sensor heads.

17. The lidar system of claim 16, wherein the plurality of sub-portions of the one or more optical signals comprising a plurality of wavelengths of light are emitted by a plurality of the one or more light sources respectively operating at the plurality of wavelengths or by a tunable light source operating at the plurality of wavelengths.

18. The lidar system of claim 1, wherein the demultiplexer comprises an optical power splitter, an optical switch, or a wavelength demultiplexer.

19. The lidar system of claim 1, wherein:

the plurality of sensor heads are provided about a vehicle; and

stronger ones of the sub-portions of each of the plurality of pulses are provided to forward-facing sensor heads on the vehicle.

20. The lidar system of claim 1, wherein:

the plurality of sensor heads are provided about a vehicle; and

weaker ones of the sub-portions of each of the plurality of pulses are provided to rear-facing sensor heads on the vehicle.

21. The lidar system of claim 1, wherein a plurality of the one or more optical amplifiers respectively comprise the plurality of optical links.

22. A lidar system comprising:

one or more light sources configured to produce one or more optical signals, wherein;

the one or more light sources comprise one or more seed lasers configured to produce the one or more optical signals; and

the one or more optical signals comprise a first pulse and a second pulse;

a demultiplexer configured to separate the one or more optical signals into a plurality of sub-portions and to distribute the plurality of sub-portions of the one or more optical signals via a plurality of optical links;

a plurality of sensor heads configured to respectively receive the plurality of sub-portions of the one or more optical signals via the plurality of optical links, the plurality of sensor heads further being configured to emit the plurality of sub-portions of the one or more optical signals into a plurality of fields of view and to detect reflected or scattered light from the plurality of fields of view;

one or more optical amplifiers configured to amplify the one or more optical signals or the plurality of sub-portions of the one or more optical signals, wherein the one or more light sources further comprise one or more supplemental light sources whose light is combined with that of the one or more seed lasers prior to amplification in order to reduce the likelihood of at least one of the one or more optical amplifiers spontaneously emitting amplified light during a time between the first pulse and the second pulse; and

one or more filters configured to reduce amplified spontaneous emission produced by the one or more optical amplifiers.

23. The lidar system of claim 22, wherein the plurality of sensor heads respectively comprise a plurality of processors, each of the plurality of processors being configured to determine a distance to a target based on at least a portion of the reflected or scattered light.

24. The lidar system of claim 22, wherein the lidar system is incorporated into a vehicle.

25. The lidar system of claim 22, wherein the demultiplexer comprises an optical power splitter, an optical switch, or a wavelength demultiplexer.