# US 12,111,400 B2 · FMCW LIDAR system with passive amplitude modulation for simultaneous determination of range and velocity > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,111,400 B2 - Document ID: US12111400B2 - Status: Granted - Kind: B2 - Application number: 17/881,431 - Filed: 2022-08-04 - Published: 2022-11-24 - Granted: 2024-10-08 - Earliest claimed: 2021-04-15 - Assignees: Aeva, Inc. - Applicants: Aeva, Inc. - Inventors: Behsan Behzadi; Mina Rezk; Kumar Bhargav Viswanatha; Esha John - Web page: https://patentgrep.com/patent/US12111400B2 ## CPC - G01S 7/4812: {transmitted and received beams following a coaxial path} - G01S 17/931: of land vehicles - G01S 7/4816: {of receivers alone} - G01S 7/4817: {relating to scanning} - 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 7/4911: Transmitters - G01S 7/4913: Circuits for detection, sampling, integration or read-out - G01S 7/4915: Time delay measurement, e.g. operational details for pixel components (signal extraction and conditioning G01S7/493); Phase measurement - G01S 7/499: using polarisation effects - G01S 17/06: Systems determining position data of a target - 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 17/32: using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated - G01S 17/34: using transmission of continuous, frequency-modulated waves while heterodyning the received signal, or a signal derived therefrom, with a locally-generated signal related to the contemporaneously transmitted signal - G01S 17/36: with phase comparison between the received signal and the contemporaneously transmitted signal - G01S 17/42: Simultaneous measurement of distance and other co-ordinates (indirect measurement G01S17/46) - G01S 17/58: Velocity or trajectory determination systems; Sense-of-movement determination systems - G01S 17/86: Combinations of lidar systems with systems other than lidar, radar or sonar, e.g. with direction finders - G01S 17/89: for mapping or imaging - G01S 17/933: of aircraft or spacecraft - G05D 1/0231: {using optical position detecting means (position-fixing by using electromagnetic waves other than radio waves, e.g. optical position detecting means G01S5/16)} - G05D 1/249: from positioning sensors located off-board the vehicle, e.g. from cameras - 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 - G05D: SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES ## Abstract A light detection and ranging (LIDAR) system has a passive modulator to modulate a light signal from an optical source with a low-power mode at a section of a sweep signal to generate a pulsed light signal transmitted towards a target. The LIDAR system has a photodetector to receive a return beam from the target with an amplitude modulated (AM) signal portion and a frequency modulated (FM) signal portion. The LIDAR system determines a target range value for the target based on the AM signal portion and determines a target velocity value for the target based on the FM signal portion. ## Claims ### Claim 1 A frequency modulated continuous wave (FMCW) light detection and ranging (LIDAR) system, comprising: a frequency modulated continuous wave (FMCW) optical source to transmit a light signal; a passive modulator to modulate the light signal with a low-power mode at a section of a sweep signal to generate a pulsed light signal transmitted towards a target; a photodetector to receive a return beam from the target based on the pulsed light signal, the return beam including an amplitude modulated (AM) signal portion and a frequency modulated (FM) signal portion; and a processor coupled to the photodetector configured to: determine a target range value for the target based on the AM signal portion; and determine a target velocity value for the target based on the AM signal portion and based on the FM signal portion. ### Claim 2 (depends on 1) The FMCW LIDAR system of claim 1, wherein the FM signal portion comprises a first FM signal portion, and further comprising: the passive modulator to modulate a portion of the light signal to produce a second FM signal portion transmitted towards a local oscillator; and the photodetector to combine the second FM signal portion with the first FM signal portion to determine the target velocity value. ### Claim 3 (depends on 1) The FMCW LIDAR system of claim 1, wherein the passive modulator is further to: modulate, for a period of time, the light signal at the section of the sweep signal, wherein the section is after a transition from an upsweep signal to a downsweep signal. ### Claim 4 (depends on 1) The FMCW LIDAR system of claim 1, wherein the passive modulator is further to: modulate, for a period of time, the light signal at the section of the sweep signal, wherein the section is after a transition from a downsweep signal to an upsweep signal. ### Claim 5 (depends on 1) The FMCW LIDAR system of claim 1, wherein the passive modulator is further to: modulate, for a period of time, the light signal at the section of the sweep signal, wherein the section is after a transition between an upsweep signal and a downsweep signal. ### Claim 6 (depends on 1) The FMCW LIDAR system of claim 1, wherein the low-power mode comprises the passive modulator to turn off frequency modulation of the light signal for a period of time. ### Claim 7 (depends on 1) The FMCW LIDAR system of claim 1, wherein the passive modulator comprises a Mach-Zehnder interferometer (MZI). ### Claim 8 (depends on 1) The FMCW LIDAR system of claim 1, wherein the passive modulator comprises a saturable absorber. ### Claim 9 (depends on 1) The FMCW LIDAR system of claim 1, wherein the passive modulator comprises a ring resonator. ### Claim 10 A method for light detection and ranging (LIDAR), comprising: transmitting a light signal from a frequency modulated continuous wave (FMCW) source; modulating, with a passive modulator, the light signal with a low-power mode at a section of a sweep signal to generate a pulsed light signal transmitted towards a target; receiving a return beam from the target based on the pulsed light signal, the return beam including an amplitude modulated (AM) signal portion and a frequency modulated (FM) signal portion; and determining a target range value for the target based on the AM signal portion; and determining a target velocity value for the target based on the AM signal portion and based on the FM signal portion. ### Claim 11 (depends on 10) The method of claim 10, wherein the FM signal portion comprises a first FM signal portion, and further comprising: modulating a portion of the light signal to produce a second FM signal portion transmitted towards a local oscillator; and combining the second FM signal portion with the first FM signal portion to determine the target velocity value. ### Claim 12 (depends on 10) The method of claim 10, wherein modulating the light signal at the section of the sweep signal comprises: modulating, for a period of time, the light signal at the section of the sweep signal, wherein the section is after a transition from an upsweep signal to a downsweep signal. ### Claim 13 (depends on 10) The method of claim 10, wherein modulating the light signal at the section of the sweep signal comprises: modulating, for a period of time, the light signal at the section of the sweep signal, wherein the section is after a transition from a downsweep signal to an upsweep signal. ### Claim 14 (depends on 10) The method of claim 10, wherein modulating the light signal at the section of the sweep signal comprises: modulating, for a period of time, the light signal at the section of the sweep signal, wherein the section is after a transition between an upsweep signal and a downsweep signal. ### Claim 15 (depends on 10) The method of claim 10, wherein modulating the light signal with the low-power mode comprises: turning off FM modulation of the light signal for a period of time. ### Claim 16 A light detection and ranging (LIDAR) system, comprising: a frequency modulated continuous wave (FMCW) light source to generate a light signal; an optical circuit including: an optical source to transmit the light signal; a passive modulator to modulate the light signal with a low-power mode at a section of a sweep signal to generate a pulsed light signal transmitted towards a target; and a photodetector to receive a return beam from the target based on the pulsed light signal, the return beam including an amplitude modulated (AM) signal portion and a frequency modulated (FM) signal portion; a processing device coupled to the photodetector configured to: determine a target range value for the target based on the AM signal portion; and determine a target velocity value for the target based on the AM signal portion and based on the FM signal portion; and optics to transmit the pulsed light signal from the optical circuit and direct the return beam to the photodetector. ### Claim 17 (depends on 16) The LIDAR system of claim 16, wherein the FM signal portion comprises a first FM signal portion, and further comprising: the passive modulator to modulate a portion of the light signal to produce a second FM signal portion transmitted towards a local oscillator; and the photodetector to combine the second FM signal portion with the first FM signal portion to determine the target velocity value. ### Claim 18 (depends on 16) The LIDAR system of claim 16, wherein the passive modulator is further to: modulate, for a period of time, the light signal at the section of the sweep signal, wherein the section is after a transition between an upsweep signal and a downsweep signal. ### Claim 19 (depends on 16) The LIDAR system of claim 16, wherein the passive modulator is further to: modulate, for a period of time, the light signal at the section of the sweep signal, wherein the section is after a transition between an upsweep signal and a downsweep signal. ### Claim 20 (depends on 16) The LIDAR system of claim 16, wherein the low-power mode comprises the passive modulator to stop frequency modulation of the light signal for a period of time.