# US 2018/0024241 A1 · Lidar system

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- Number: US 2018/0024241 A1
- Document ID: US20180024241A1
- Status: Published application
- Kind: A1
- Application number: 15/470,708
- Filed: 2017-03-27
- Published: 2018-01-25
- Earliest claimed: 2015-11-30
- Assignees: Luminar Technologies, Inc.
- Applicants: Luminar Technologies, Inc.
- Inventors: Jason M. Eichenholz; Austin K. Russell; Scott R. Campbell; Alain Villeneuve; Rodger W. Cleye; Joseph G. LaChapelle; Matthew D. Weed; Lane A. Martin
- Web page: https://patentgrep.com/patent/US20180024241A1

## CPC

- 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
- G01S 7/4804: {Auxiliary means for detecting or identifying lidar signals or the like, e.g. laser illuminators}
- G01S 7/4811: {common to transmitter and receiver}
- G01S 7/4814: {of transmitters alone}
- G01S 7/4815: {using multiple transmitters}
- G01S 7/4816: {of receivers alone}
- G01S 7/4817: {relating to scanning}
- G01S 7/4818: {using optical fibres}
- G01S 7/483: Details of pulse systems
- G01S 7/484: Transmitters
- G01S 7/4861: Circuits for detection, sampling, integration or read-out
- G01S 7/4863: Detector arrays, e.g. charge-transfer gates
- 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)
- G01S 7/4873: {by deriving and controlling a threshold value}
- G01S 7/4876: {by removing unwanted signals (G01S7/495 takes precedence)}
- G01S 17/00: Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
- G01S 17/02: Systems using the reflection of electromagnetic waves other than radio waves (G01S17/66 takes precedence)
- G01S 17/06: Systems determining position data of a target
- G01S 17/08: for measuring distance only (indirect measurement G01S17/46; active triangulation systems G01S17/48)
- G01S 17/10: using transmission of interrupted, pulse-modulated waves (determination of distance by phase measurements G01S17/32)
- G01S 17/26: wherein the transmitted pulses use a frequency-modulated or phase-modulated carrier wave, e.g. for pulse compression of received signals
- G01S 17/42: Simultaneous measurement of distance and other co-ordinates (indirect measurement G01S17/46)
- G01S 17/88: Lidar systems specially adapted for specific applications
- G01S 17/89: for mapping or imaging
- G01S 17/931: of land vehicles
- 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)}
- H01S 3/0078: {Frequency filtering}
- H01S 3/0085: {Modulating the output, i.e. the laser beam is modulated outside the laser cavity}
- H01S 3/06733: {Fibre having more than one cladding}
- H01S 3/0675: {Resonators including a grating structure, e.g. distributed Bragg reflectors [DBR] or distributed feedback [DFB] fibre lasers}
- H01S 3/06754: {Fibre amplifiers (H01S3/06708 takes precedence)}
- H01S 3/06758: {Tandem amplifiers}
- H01S 3/08086: {Multiple-wavelength emission}
- H01S 3/094003: {the pumped medium being a fibre}
- H01S 3/094042: {of a fibre laser}
- H01S 3/094076: {Pulsed or modulated pumping (H01S3/1024 takes precedence)}
- H01S 3/0941: of a laser diode
- H01S 3/10023: {by functional association of additional optical elements, e.g. filters, gratings, reflectors}
- H01S 3/1106: Mode locking
- H01S 5/4012: {Beam combining, e.g. by the use of fibres, gratings, polarisers, prisms}
- H01S 5/4087: {emitting more than one wavelength}
- G01S 17/32: using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated
- H01S 3/1608: {erbium}
- H01S 3/2383: {Parallel arrangements}
- H01S 5/0057: {for temporal shaping, e.g. pulse compression, frequency chirping}
- H01S 5/0085: {for modulating the output, i.e. the laser beam is modulated outside the laser cavity}
- H01S 2301/02: ASE (amplified spontaneous emission), noise; Reduction thereof
- G01S: RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- H01S: DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL

## Abstract

A lidar system with a pulsed laser diode configured to produce an optical seed pulse of light at an operating wavelength between approximately 1400 nm and approximately 1600 nm. The lidar system may also include an optical amplifier configured to amplify the optical seed pulse to produce an eye-safe output optical pulse that is emitted into a field of view. The optical amplifier may produce an amount of amplified spontaneous emission (ASE) associated with the output optical pulse. The lidar system may include an optical filter configured to filter the output optical pulse to reduce the associated ASE. The lidar system may also include a receiver configured to detect at least a portion of the output optical pulse reflected or scattered from the field of view.

## Claims

### Claim 1

A lidar system comprising:
a pulsed laser diode configured to produce a plurality of optical seed pulses of light at an operating wavelength between approximately 1400 nm and approximately 1600 nm;
an optical amplifier configured to amplify the optical seed pulses to produce a plurality of eye-safe output optical pulses that are emitted into a field of view, the optical amplifier producing an amount of amplified spontaneous emission (ASE) associated with the output optical pulses, wherein the plurality of output optical pulses have characteristics comprising:
a pulse repetition frequency of less than or equal to 100 MHz;
a pulse duration of less than or equal to 20 nanoseconds; and
a duty cycle of less than or equal to 1%;
an optical filter configured to filter the output optical pulses to reduce the associated ASE; and
a receiver configured to detect at least a portion of the output optical pulses reflected or scattered from the field of view.

### Claim 2 (depends on 1)

The lidar system of claim 1, wherein the receiver is provided in a sensor head remotely located from the pulsed laser diode, and wherein the sensor head is coupled to the pulsed laser diode or the optical amplifier by an optical link.

### Claim 3 (depends on 2)

The lidar system of claim 2, wherein:
the lidar system further comprises one or more additional sensor heads, wherein the pulsed laser diode or the optical amplifier is coupled to each of the additional sensor heads by a respective optical link which conveys a respective portion of the optical seed pulses or the output optical pulses to each of the additional sensor heads.

### Claim 4 (depends on 3)

The lidar system of claim 3, wherein the lidar system is incorporated into a vehicle, and wherein the sensor head and the one or more additional sensor heads are positioned about the vehicle to provide at least a 180-degree view of an environment around the vehicle.

### Claim 5 (depends on 1)

The lidar system of claim 1, wherein the lidar system has a maximum range of at least 50 meters.

### Claim 6 (depends on 1)

The lidar system of claim 1, wherein:
the lidar system comprises a scanner configured to scan at least a portion of the output optical pulses across a horizontal field of regard of at least 25 degrees and a vertical field of regard of at least 5 degrees.

### Claim 7 (depends on 1)

The lidar system of claim 1, wherein:
the lidar system comprises a scanner configured to scan at least a portion of the output optical pulses with a horizontal resolution of at least 100 pixels and a vertical resolution of at least 4 pixels.

### Claim 8

(canceled)

### Claim 9 (depends on 1)

The lidar system of claim 1, wherein the pulsed laser diode comprises a distributed-feedback (DFB) laser or a distributed-Bragg reflector (DBR) laser.

### Claim 10 (depends on 1)

The lidar system of claim 1, wherein the optical amplifier comprises a booster amplifier with a double-clad gain fiber having erbium dopants or erbium and ytterbium dopants.

### Claim 11

(canceled)

### Claim 12

(canceled)

### Claim 13 (depends on 1)

The lidar system of claim 1, wherein the characteristics further comprise:
a pulse energy of at least 10 nanojoules;
a peak power of at least 1 watt; and
an average power of no more than 50 watts.

### Claim 14 (depends on 1)

The lidar system of claim 1, wherein the optical filter is configured to transmit light at one or more wavelengths comprising the operating wavelength and to attenuate light away from the transmitted wavelengths by at least 10 dB.

### Claim 15

(canceled)

### Claim 16

A lidar system comprising:
a pulsed laser diode configured to produce a plurality of optical seed pulses of light at an operating wavelength between approximately 1400 nm and approximately 1600 nm;
an optical amplifier configured to amplify the optical seed pulses to produce a plurality of output optical pulses comprising an eye-safe output optical pulse that is emitted into a field of view, the optical amplifier producing an amount of amplified spontaneous emission (ASE) associated with the output optical pulses;
an optical filter configured to filter the output optical pulses to reduce the associated ASE;
a scanner configured to scan at least a portion of the output optical pulses; and
a receiver configured to detect at least a portion of the output optical pulses reflected or scattered from the field of view,
wherein the lidar system is configured to generate point clouds of distance measurements at a rate between approximately 0.1 frames per second and approximately 1,000 frames per second.

### Claim 17 (depends on 16)

The lidar system of claim 16, wherein the receiver is provided in a sensor head remotely located from the pulsed laser diode, and wherein the sensor head is coupled to the pulsed laser diode or the optical amplifier by an optical link.

### Claim 18 (depends on 16)

The lidar system of claim 16, wherein the scanner is configured to scan the portion of the output optical pulses across a horizontal field of regard of at least 25 degrees and a vertical field of regard of at least 5 degrees.

### Claim 19 (depends on 16)

The lidar system of claim 16, wherein the scanner is configured to scan the portion of the output optical pulses with a horizontal resolution of at least 100 pixels and a vertical resolution of at least 4 pixels.

### Claim 20

A lidar system comprising:
a plurality of pulsed laser diodes, each pulsed laser diode being configured to produce optical seed pulses of light at a different operating wavelength between approximately 1400 nm and approximately 1600 nm;
an optical multiplexer configured to combine the optical seed pulses produced by each laser diode into a single optical fiber;
an optical amplifier configured to amplify the combined optical seed pulses to produce a plurality of output optical pulses comprising an eye-safe output optical pulse that is emitted into a field of view, the optical amplifier producing an amount of amplified spontaneous emission (ASE) associated with the output optical pulses;
an optical filter configured to filter the output optical pulses to reduce the associated ASE; and
a receiver configured to detect at least a portion of the output optical pulses reflected or scattered from the field of view.

### Claim 21 (depends on 20)

The lidar system of claim 20, wherein the receiver is provided in a sensor head remotely located from the plurality of pulsed laser diodes, and wherein the sensor head is coupled to the pulsed laser diodes or the optical amplifier by an optical link.

### Claim 22 (depends on 21)

The lidar system of claim 21, wherein the lidar system further comprises one or more additional sensor heads, wherein the optical amplifier is coupled to each of the additional sensor heads by a respective optical link which conveys a respective portion of the optical seed pulses or the output optical pulses to each of the additional sensor heads.

### Claim 23 (depends on 20)

The lidar system of claim 20, further comprising a scanner configured to scan at least a portion of the output optical pulses across a horizontal field of regard of at least 25 degrees and a vertical field of regard of at least 5 degrees.

### Claim 24 (depends on 20)

The lidar system of claim 20, wherein the optical amplifier comprises a booster amplifier with a double-clad gain fiber having erbium dopants or erbium and ytterbium dopants.