# US 11,994,539 B2 · Optical voltage probe > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,994,539 B2 - Document ID: US11994539B2 - Status: Granted - Kind: B2 - Application number: 17/770,292 - Filed: 2021-03-26 - Published: 2022-09-15 - Granted: 2024-05-28 - Earliest claimed: 2020-04-07 - Assignees: Seikoh Giken Co., Ltd.; Rohm Co., Ltd. - Applicants: SEIKOH GIKEN Co., Ltd.; Rohm Co., Ltd. - Inventors: Ryuji Osawa; Noriaki Hiraga - Web page: https://patentgrep.com/patent/US11994539B2 ## CPC - G01R 15/22: using light-emitting devices, e.g. LED, optocouplers {(G01R31/31901 takes precedence)} - G01R 1/071: {containing electro-optic elements} - G01R 15/241: {using electro-optical modulators, e.g. electro-absorption (probes containing electro-optic elements G01R1/071)} - G01R 19/0084: {Measuring voltage only} - G02F 1/0327: {Operation of the cell; Circuit arrangements (G02F1/05 takes precedence)} - G02F 1/035: in an optical waveguide structure - G02F 1/2252: {in optical fibres} - G02F 2201/02: fibre - G02F 2202/20: LiNbO3, LiTaO3 - G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12) - G02F: OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS ## Abstract An optical voltage probe includes: an optical modulator 1 having two modulation electrodes 11 and 12, the optical modulator 1 being configured to modulate an intensity of an incident light depending on a voltage between the two modulation electrodes and output the incident light which is modulated; an input/output optical fiber 2 connected with the optical modulator 1; two contact terminal attachment portions 5, 6 to which contact terminals 3, 4 can be detachably attached and contacted, the two contact terminals 3, 4 being configured to be in contact with the points to be measured, the two contact terminal attachment portions 5, 6 being respectively connected with the modulation electrodes 11, 12; and a package 8 that houses the optical modulator 1 and a part of the input/output optical fiber 2. A voltage signal induced via the contact terminals 3, 4 is converted into an optical intensity modulation signal. When an electric wave having a measurement frequency is applied while the contact terminal attachment portions 5, 6 are opened, the package 8 exhibits a shielding effect of attenuating the electric wave by 15 dB or more compared to an output signal intensity measured without providing the package. ## Claims ### Claim 1 An optical voltage probe comprising: an optical modulator having at least two modulation electrodes, the optical modulator being configured to modulate an intensity of an incident light depending on a voltage between the two modulation electrodes and output the incident light which is modulated; an input optical fiber that is connected with the optical modulator; an output optical fiber that is connected with the optical modulator; two contact terminals or two contact terminal attachment portions to which the two contact terminals can be detachably attached and contacted, the two contact terminals being connected with the two modulation electrodes and configured to be in contact with points to be measured; a package that houses the optical modulator, a part of the input optical fiber and a part of the output optical fiber, wherein a voltage signal induced between the two modulation electrodes via the two contact terminals is converted into an optical intensity modulation signal by the optical modulator and the optical intensity modulation signal is outputted through the output optical fiber so that the voltage signal induced between the two modulation electrodes is measured based on the optical intensity modulation signal, the package has a layered or sheet-shaped metal body covering an inside of the package, and when an electric wave having a measurement frequency is applied while the two contact terminals or the two contact terminal attachment portions are opened, the package exhibits a shielding effect of attenuating the electric wave by 15 dB or more compared to an output signal intensity measured without providing the package. ### Claim 2 An optical voltage probe comprising: an optical modulator having at least two modulation electrodes, the optical modulator being configured to modulate an intensity of an incident light depending on a voltage between the two modulation electrodes and output the incident light which is modulated; an input optical fiber that is connected with the optical modulator; an output optical fiber that is connected with the optical modulator; two contact terminal attachment portions to which two contact terminals can be detachably attached and contacted, the two contact terminals being connected with the two modulation electrodes and configured to be in contact with the points to be measured; and a package that houses the optical modulator, a part of the input optical fiber and a part of the output optical fiber, wherein the two contact terminal attachment portions are installed inner than a position of a surface of the package, a voltage signal induced between the two modulation electrodes via the two contact terminal is converted into an optical intensity modulation signal by the optical modulator and the optical intensity modulation signal is outputted through the output optical fiber so that the voltage signal induced between the two modulation electrodes is measured based on the optical intensity modulation signal, and when an electric wave having a measurement frequency is applied while the two contact terminal attachment portions are opened, the package exhibits a shielding effect of attenuating the electric wave by 15 dB or more compared to an output signal intensity measured without providing the package. ### Claim 3 An optical voltage probe comprising: an optical modulator having at least two modulation electrodes, the optical modulator being configured to modulate an intensity of an incident light depending on a voltage between the two modulation electrodes and output the incident light which is modulated; an input optical fiber that is connected with the optical modulator; an output optical fiber that is connected with the optical modulator; two contact terminals or two contact terminal attachment portions to which the two contact terminals can be detachably attached and contacted, the two contact terminals being connected with the two modulation electrodes and configured to be in contact with points to be measured; a package that houses the optical modulator, a part of the input optical fiber and a part of the output optical fiber, wherein a voltage signal induced between the two modulation electrodes via the two contact terminals is converted into an optical intensity modulation signal by the optical modulator and the optical intensity modulation signal is outputted through the output optical fiber so that the voltage signal induced between the two modulation electrodes is measured based on the optical intensity modulation signal, the package includes an electric wave absorber for reducing a reflection of an electromagnetic wave arrived from an outside of the package and reflected by the package, and when an electric wave having a measurement frequency is applied while the two contact terminals or the two contact terminal attachment portions are opened, the package exhibits a shielding effect of attenuating the electric wave by 15 dB or more compared to an output signal intensity measured without providing the package. ### Claim 4 (depends on 3) The optical voltage probe according to claim 3, wherein the electric wave absorber is a sheet-shaped electric wave absorber provided on a surface of the package. ### Claim 5 (depends on 3) The optical voltage probe according to claim 3, wherein the package exhibits the shielding effect by reducing a transmission of the electric wave by the electric wave absorber. ### Claim 6 (depends on 1) The optical voltage probe according to claim 1, wherein an interval between the two contact terminals or between the two contact terminal attachment portions is 3 mm or more. ### Claim 7 (depends on 1) The optical voltage probe according to claim 1, wherein the optical modulator is a branch interference type optical modulator using an optical waveguide formed on a lithium niobate crystal substrate. ### Claim 8 (depends on 7) The optical voltage probe according to claim 7, wherein the optical modulator is a reflection type optical modulator where the incident light is reflected inside the optical modulator to change a direction of the incident light, and the input optical fiber and the output optical fiber are formed by one input/output optical fiber. ### Claim 9 (depends on 7) The optical voltage probe according to claim 7, wherein at least one electrode capacitively coupled with the two modulation electrodes is provided between the two modulation electrodes. ### Claim 10 (depends on 4) The optical voltage probe according to claim 4, wherein the package exhibits the shielding effect by reducing a transmission of the electric wave by the electric wave absorber. ### Claim 11 (depends on 2) The optical voltage probe according to claim 2, wherein an interval between the two contact terminals or between the two contact terminal attachment portions is 3 mm or more. ### Claim 12 (depends on 3) The optical voltage probe according to claim 3, wherein an interval between the two contact terminals or between the two contact terminal attachment portions is 3 mm or more. ### Claim 13 (depends on 2) The optical voltage probe according to claim 2, wherein the optical modulator is a branch interference type optical modulator using an optical waveguide formed on a lithium niobate crystal substrate. ### Claim 14 (depends on 3) The optical voltage probe according to claim 3, wherein the optical modulator is a branch interference type optical modulator using an optical waveguide formed on a lithium niobate crystal substrate. ### Claim 15 (depends on 4) The optical voltage probe according to claim 4, wherein the optical modulator is a branch interference type optical modulator using an optical waveguide formed on a lithium niobate crystal substrate. ### Claim 16 (depends on 5) The optical voltage probe according to claim 5, wherein the optical modulator is a branch interference type optical modulator using an optical waveguide formed on a lithium niobate crystal substrate. ### Claim 17 (depends on 13) The optical voltage probe according to claim 13, wherein the optical modulator is a reflection type optical modulator where the incident light is reflected inside the optical modulator to change a direction of the incident light, and the input optical fiber and the output optical fiber are formed by one input/output optical fiber. ### Claim 18 (depends on 14) The optical voltage probe according to claim 14, wherein the optical modulator is a reflection type optical modulator where the incident light is reflected inside the optical modulator to change a direction of the incident light, and the input optical fiber and the output optical fiber are formed by one input/output optical fiber. ### Claim 19 (depends on 13) The optical voltage probe according to claim 13, wherein at least one electrode capacitively coupled with the two modulation electrodes is provided between the two modulation electrodes. ### Claim 20 (depends on 14) The optical voltage probe according to claim 14, wherein at least one electrode capacitively coupled with the two modulation electrodes is provided between the two modulation electrodes.