# US 11,079,323 B2 · Method of frequency comb generation, associated generation module, remote spectroscopy method and associated spectroscopy device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,079,323 B2 - Document ID: US11079323B2 - Status: Granted - Kind: B2 - Application number: 15/986,499 - Filed: 2018-05-22 - Published: 2018-11-29 - Granted: 2021-08-03 - Earliest claimed: 2017-05-23 - Assignees: Centre National D'Etudes Spatiales; Office National d'Etudes et de Recherches Aerospatiales - Applicants: Centre National D'Etudes Spatiales; Office National d'Etudes et de Recherches Aérospatiales - Inventors: Philippe Hébert; François Lemaître; Xavier Orlik; Thibault Dartigalongue - Web page: https://patentgrep.com/patent/US11079323B2 ## CPC - G01N 21/39: using tunable lasers - G01S 7/4802: {using analysis of echo signal for target characterisation; Target signature; Target cross-section} - G01S 7/484: Transmitters - G01S 17/88: Lidar systems specially adapted for specific applications - G01N 2021/1795: {Atmospheric mapping of gases} - G01N 2021/394: {DIAL method} - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) - 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 ## Abstract A method of generating frequency combs composed of a predetermined number of rays, wherein the method includes the modulation of a main ray generated by a laser source (20), by a first radiofrequency signal at a first frequency value, by a second radio frequency signal at a second frequency value, and by a third radio frequency signal at a third frequency value. The second frequency value is equal to twice the first frequency value. The third frequency value is equal to three times the first frequency value. ## Claims ### Claim 1 A method of generating frequency combs composed of a predetermined number of rays, the method comprising: modulation of a main ray generated by a laser source, by a first radiofrequency signal at a first frequency value, by a second radiofrequency signal at a second frequency value, and by a third radiofrequency signal at a third frequency value; the second frequency value being equal to twice the first frequency value; the third frequency value being equal to three times the first frequency value; and wherein the modulation by the first radiofrequency signal is performed with a modulation amplitude substantially equal to 1.6418 radians and a relative phase shift substantially equal to 21.8°. ### Claim 2 (depends on 1) The method according to claim 1, wherein the frequency comb is composed of thirteen rays regularly spaced from each other by the first frequency value and substantially equal to each other in power. ### Claim 3 (depends on 1) The method according to claim 1, wherein the modulation by the second radiofrequency signal is performed with a modulation amplitude substantially equal to 1.3549 radians and a relative phase shift substantially equal to 43.6°. ### Claim 4 (depends on 1) The method according to claim 1, wherein the modulation by the third radiofrequency signal is performed with a modulation amplitude substantially equal to 2.2829 radians and a relative phase shift substantially equal to 245.4°. ### Claim 5 (depends on 1) The method according to claim 1, comprising the following steps: A) generation of the main ray by the laser source; B) generation of a first plurality of rays by modulating the main ray by one of the first radiofrequency signal, the second radiofrequency signal, or the third radiofrequency signal; C) generation of a second plurality of rays by modulating each ray of the first plurality of rays with one of the first radiofrequency signal, the second radiofrequency signal, or the third radiofrequency signal other than the radiofrequency signal used in step B); D) generation of a third plurality of rays by modulating each ray of the second plurality of rays with one of the first radiofrequency signal, the second radiofrequency signal, or the third radiofrequency signal other than the radiofrequency signals used in steps B) and C); and E) formation of a comb from the rays of the third plurality of rays. ### Claim 6 (depends on 1) The method according to claim 1, comprising the following steps: A′) generation of the main ray by the laser source; B′) generation of a complex signal corresponding to a sum of the first radiofrequency signal, the second radiofrequency signal, or the third radiofrequency signal; C′) generation of a main plurality of rays by modulating the main ray by the complex signal; and D′) formation of a comb from the rays of the main plurality of rays. ### Claim 7 (depends on 5) The method according to claim 5, further comprising a step of modulating comb rays at an additional frequency value greater than the third frequency value. ### Claim 8 (depends on 6) The method according to claim 6, further comprising a step of modulating comb rays at an additional frequency value greater than the third frequency value. ### Claim 9 (depends on 7) The method according to claim 7, wherein the additional frequency value is between 20 and 40 GHz. ### Claim 10 (depends on 1) A frequency comb generation module, the comb being composed of the predetermined number of rays, the module being configured to implement the method according to claim 1. ### Claim 11 (depends on 1) A method of LIDAR-type remote spectroscopy of a targeted material, comprising the following steps: generation of a transmission signal comprising at least one comb generated according to the method according to claim 1; transmission of the transmission signal to the targeted material; reception of a response signal corresponding to the transmission signal reflected by the targeted material; and analysis of the response signal. ### Claim 12 (depends on 11) The method according to claim 11, wherein the first frequency value is selected based on the physical characteristics of the targeted material. ### Claim 13 (depends on 11) A LIDAR remote spectroscopy device configured to implement the method according to claim 11.