# US 10,309,769 B2 · Light source device and measuring instrument using change over time of intensity of mode-locked oscillated output light > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,309,769 B2 - Document ID: US10309769B2 - Status: Granted - Kind: B2 - Application number: 15/769,421 - Filed: 2016-06-30 - Published: 2018-10-25 - Granted: 2019-06-04 - Earliest claimed: 2015-10-23 - Assignees: Pusan National University Industry-University Cooperation Foundation - Applicants: Pusan National University Industry-University Cooperation Foundation - Inventors: Changseok Kim; Hwidon Lee; Myungyung Jeong; Gyeonghun Kim - Web page: https://patentgrep.com/patent/US10309769B2 ## CPC - G01B 11/2441: {using interferometry} - G01B 9/02091: Tomographic interferometers, e.g. based on optical coherence - H01S 3/08: Construction or shape of optical resonators or components thereof - H01S 3/094: by coherent light - H01S 3/1109: Active mode locking - H01S 3/083: Ring lasers {(fibre ring lasers H01S3/06791)} - H01S 3/1024: {for pulse generation} - H01S 3/107: using electro-optic devices, e.g. exhibiting Pockels or Kerr effect {(H01S3/1061, H01S3/1063, H01S3/1065 take precedence)} - G01B: MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS - 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 The present invention relates to a light source device and a measuring device which use a change in mode-locked resonated output light over time using a change in a cycle of an electrical signal corresponding to a change in the intensity of the output light according to a mode locking condition for each of different light paths in a resonator. The light source device includes an electrical signal generator configured to control the intensity of an optical signal from the light source device, and an optical gain unit controlled by periodic electrical signals having cycles calculated by dividing a round-trip time of photons corresponding to each of different light paths by an integer multiple. The intensity of the optical signal is controlled by the optical gain unit. ## Claims ### Claim 1 A light source device using a change in intensity of mode-locked oscillated output light over time, the light source device comprising: an electrical signal generator configured to control intensity of an optical signal from the light source device; and an optical gain unit configured to be controlled by a periodic electrical signal having a cycle calculated by dividing a round-trip time of a photon corresponding to each of different light paths by an integer multiple; and a reflector configured to generate a reflective signal at a specific light path distance such that the reflective signal is oscillated at a maximum level when a specific periodic electrical signal corresponding to a mode locking condition is applied, wherein the intensity of the optical signal is controlled by the optical gain unit. ### Claim 2 (depends on 1) The light source device of claim 1, wherein, in a resonator of the light source device, a reflective optical gain unit, a light splitter, and a reflector are linearly located. ### Claim 3 (depends on 1) The light source device of claim 1, wherein, in a resonator of the light source device, a transmissive optical gain unit, a partial reflector, and a reflector are linearly located. ### Claim 4 (depends on 1) The light source device of claim 1, wherein, in a resonator of the light source device, a transmissive optical gain unit, a light circulator, a reflector, and a light splitter are located in a ring structure. ### Claim 5 (depends on 1) The light source device of claim 1, wherein a resonator of the light source device comprises a reflector including a scanning emitter configured to emit and receive light while changing a position thereof over time, the reflector being in a form in which a surface and an inner shape of an object are measured on the basis of a distribution of positions according to a light path distance difference between one or multiple reflective layers of the object. ### Claim 6 (depends on 1) The light source device of claim 1, wherein a resonator of the light source device comprises a reflector including a distribution emitter configured to emit and receive light by simultaneously distributing the light to a plurality of paths, the reflector being in a form in which a surface and an inner shape of an object are measured on the basis of a distribution of positions according to a light path distance difference between one or multiple reflective layers of the object. ### Claim 7 (depends on 1) The light source device of claim 1, wherein a resonator of the light source device comprises a reflector including an optical connector configured to emit and receive light via an optical fiber, the reflector being in a form in which a state of the optical fiber is sensed and measured on the basis of a distribution of positions according to a light path distance difference between one or multiple reflective layers of the optical fiber. ### Claim 8 (depends on 1) The light source device of claim 1, wherein a resonator of the light source device comprises an electro-optic device configured to control intensity of an optical signal by receiving a periodic electrical signal, in place of the optical gain unit. ### Claim 9 A measuring device using a change in intensity of mode-locked oscillated output light over time, the measuring device comprising: an electrical signal generator configured to control intensity of an optical signal from a light source device; an optical gain unit configured to be controlled by a periodic electrical signal having a cycle time calculated by dividing a round-trip time of a photon corresponding to each of different light paths by an integer multiple; and a reflector configured to generate a reflective signal at a specific light path distance such that the reflective signal is oscillated at a maximum level when a specific periodic electrical signal corresponding to a mode locking condition is applied. ### Claim 10 (depends on 9) The measuring device of claim 9, wherein, in a resonator of the light source device, a reflective optical gain unit, a light splitter, and a reflector are linearly located. ### Claim 11 (depends on 9) The measuring device of claim 9, wherein, in a resonator of the light source device, a transmissive optical gain unit, a partial reflector, ad a reflector are linearly located. ### Claim 12 (depends on 9) The measuring device of claim 9, wherein, in a resonator of the light source device, a transmissive optical gain unit, a light circulator, a reflector, and a light splitter are located in a ring structure. ### Claim 13 (depends on 9) The measuring device of claim 9, wherein a resonator of the light source device comprises a reflector including a scanning emitter configured to emit and receive light while changing a position thereof over time, the reflector being in a form in which a surface and an inner shape of an object are measured on the basis of a distribution of positions according to a light path distance difference between one or multiple reflective layers of the object. ### Claim 14 (depends on 9) The measuring device of claim 9, wherein a resonator of the light source device comprises a reflector including a distribution emitter configured to emit and receive light by simultaneously distributing the light to a plurality of paths, the reflector being in a form in which a surface and an inner shape of an object are measured on the basis of a distribution of positions according to a light path distance difference between one or multiple reflective layers of the object. ### Claim 15 (depends on 9) The measuring device of claim 9, wherein a resonator of the light source device comprises a reflector including an optical connector configured to emit and receive light via an optical fiber, the reflector being in a form in which a state of the optical fiber is sensed and measured on the basis of a distribution of positions according to a light path distance difference between one or multiple reflective layers of the optical fiber. ### Claim 16 (depends on 9) The measuring device of claim 9, wherein a resonator of the light source device comprises an electro-optic device configured to control intensity of an optical signal by receiving a periodic electrical signal, in place of the optical gain unit. ### Claim 17 A measuring device using a change in intensity of mode-locked oscillated output light over time, the measuring device comprising: an electrical signal generator configured to output periodic electrical signals having cycles calculated by dividing a round-trip time of photons corresponding to each of different light paths by an integer multiple such that the cycles change over time; an optical gain unit configured to generate light and amplify intensity of the light, under periodic control of a periodic electrical signal; a light splitter configured to split the intensity of light at a certain ratio; and a reflector configured to generate a reflective signal at a specific light path distance such that the reflective signal is oscillated at a maximum level when a specific periodic electrical signal corresponding to a mode locking condition is applied. ### Claim 18 A measuring device using a change in intensity of mode-locked oscillated output light over time, the measuring device comprising: an electrical signal generator configured to output periodic electrical signals having cycles calculated by dividing a round-trip time of photons corresponding to each of different light paths by an integer multiple such that the cycles change over time; an optical gain unit configured to generate light and amplify intensity of the light, under periodic control of a periodic electrical signal from the electrical signal generator; a reflector configured to generate a reflective signal at a specific light path distance such that the reflective signal is oscillated at a maximum level when a specific periodic electrical signal corresponding to a mode locking condition is applied; and a partial reflector configured to transmit a part of the intensity of light and reflect the remainder. ### Claim 19 A measuring device using a change in intensity of mode-locked oscillated output light over time, the measuring device comprising: an electrical signal generator configured to output periodic electrical signals having cycles calculated by dividing a round-trip time of photons corresponding to each of different light paths by an integer multiple such that the cycles change over time; an optical gain unit configured to generate light and amplify intensity of the light, under periodic control of a periodic electrical signal from the electrical signal generator; a light circulator configured to change a propagation path of the light output from optical gain unit; a reflector configured to generate a reflective signal at a specific light path distance such that the reflective signal is oscillated at a maximum level when a specific periodic electrical signal corresponding to a mode locking condition is applied; and a light splitter configured to split the intensity of light at a certain ratio. ### Claim 20 A measuring device using a change in intensity of mode-locked oscillated output light over time, the measuring device comprising: an electrical signal generator configured to output periodic electrical signals having cycles calculated by dividing a round-trip time of photons corresponding to each of different light paths by an integer multiple such that the cycles change over time; an electro-optic device configured to be controlled by a periodic electrical signal from the electrical signal generator; an optical gain unit configured to generate light and amplify intensity of the light; a light splitter configured to split the intensity of light at a certain ratio; and a reflector configured to generate a reflective signal at a specific light path distance such that the reflective signal is oscillated at a maximum level when a specific periodic electrical signal corresponding to a mode locking condition is applied. ### Claim 21 A measuring device using a change in intensity of mode-locked oscillated output light over time, the measuring device comprising: an electrical signal generator configured to output periodic electrical signals having cycles calculated by dividing a round-trip time of photons corresponding to each of different light paths by an integer multiple such that the cycles change over time; an electro-optic device configured to be controlled by a periodic electrical signal from the electrical signal generator; an optical gain unit configured to generate light and amplify intensity of the light; a reflector configured to generate a reflective signal at a specific light path distance such that the reflective signal is oscillated at a maximum level when a specific periodic electrical signal corresponding to a mode locking condition is applied; and a partial reflector configured to transmit a part of the intensity of light and reflect the remainder. ### Claim 22 A measuring device using a change in intensity of mode-locked oscillated output light, the measuring device comprising: an electrical signal generator configured to output periodic electrical signals having cycles calculated by dividing a round-trip time of photons corresponding to each of different light paths by an integer multiple such that the cycles change over time; an electro-optic device configured to be controlled by a periodic electrical signal from the electrical signal generator; an optical gain unit configured to generate light and amplify intensity of the light; a light circulator configured to change a propagation path of the light; a reflector configured to generate a reflective signal at a specific light path distance such that the reflective signal is oscillated at a maximum level when a specific periodic electrical signal corresponding to a mode locking condition is applied; and a light splitter configured to split the intensity of light at a certain ratio.