# US 2025/0085488 A1 · Optical circuit, quantum operation device, and method for manufacturing optical circuit > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2025/0085488 A1 - Document ID: US20250085488A1 - Status: Published application - Kind: A1 - Application number: 18/956,990 - Filed: 2024-11-22 - Published: 2025-03-13 - Earliest claimed: 2022-07-13 - Assignees: Fujitsu Limited - Applicants: Fujitsu Limited - Inventors: Tetsuya MIYATAKE; Tetsuro ISHIGURO; Kenichi KAWAGUCHI - Web page: https://patentgrep.com/patent/US20250085488A1 ## CPC - G02B 6/125: Bends, branchings or intersections - G02B 6/4203: {Optical features} - G02B 6/12004: {Combinations of two or more optical elements} - G02B 6/0003: {the light guides being doped with fluorescent agents} - G02B 6/1228: {Tapered waveguides, e.g. integrated spot-size transformers (for coupling with fibres G02B6/305)} - G02B 6/305: {and having an integrated mode-size expanding section, e.g. tapered waveguide} - G02F 3/00: Optical logic elements; Optical bistable devices - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - 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 circuit includes: a first optical waveguide that extends in a first direction and uses diamond as a material; a plurality of second optical waveguides each of which uses diamond as a material, includes a color center, is coupled to the first optical waveguide, and extends in a direction different from the first direction; and a third optical waveguide that includes a material having a refractive index lower than a refractive index of diamond and coupled to the first optical waveguide. ## Claims ### Claim 1 An optical circuit comprising: a first optical waveguide that extends in a first direction and uses diamond as a material; a plurality of second optical waveguides each of which uses diamond as a material, includes a color center, is coupled to the first optical waveguide, and extends in a direction different from the first direction; and a third optical waveguide that includes a material having a refractive index lower than a refractive index of diamond, the third optical wave guide being coupled to the first optical waveguide. ### Claim 2 (depends on 1) The optical circuit according to claim 1, wherein the respective plurality of second optical waveguides are coupled to the first optical waveguide in directions in which traveling directions in the first optical waveguide of light emitted from the color centers are mutually the same. ### Claim 3 (depends on 1) The optical circuit according to claim 1, wherein the plurality of second optical waveguides is coupled to both sides of sides that face each other along the first direction of the first optical waveguide. ### Claim 4 (depends on 3) The optical circuit according to claim 3, wherein at least one of the plurality of second optical waveguides has a tapered portion whose width gradually decreases toward a coupling portion with the first optical waveguide. ### Claim 5 (depends on 1) The optical circuit according to claim 1, wherein the first optical waveguide does not include a color center. ### Claim 6 (depends on 1) The optical circuit according to claim 1, wherein each of the plurality of second optical waveguides includes a single color center. ### Claim 7 (depends on 1) The optical circuit according to claim 1, wherein the first optical waveguide and the second optical waveguides are integrally configured. ### Claim 8 (depends on 1) The optical circuit according to claim 1, wherein a structure in which the first optical waveguide and the third optical waveguide are laminated is included. ### Claim 9 (depends on 8) The optical circuit according to claim 8, wherein the third optical waveguide includes a first portion coupled to one end of the first optical waveguide in the first direction and a second portion coupled to the other end of the first optical waveguide in the first direction, and a support portion that supports the first optical waveguide and the second optical waveguide is further provided between the first portion and the second portion. ### Claim 10 (depends on 1) The optical circuit according to claim 1, wherein at least one of the plurality of second optical waveguides includes: a fourth optical waveguide that is coupled to the first optical waveguide and extends in a second direction different from the first direction; and a plurality of fifth optical waveguides each of which includes a color center and is coupled to the fourth optical waveguide. ### Claim 11 A method for manufacturing an optical circuit, the method comprising: forming a plurality of color centers in a first member that uses diamond as a material by implanting impurities into the first member; and acquiring, from the first member, an optical circuit that includes a first optical waveguide that extends in a first direction and a plurality of second optical waveguides each of which includes at least one of the plurality of color centers, is coupled to the first optical waveguide, and extends in a direction different from the first direction. ### Claim 12 (depends on 11) The method for manufacturing an optical circuit according to claim 11, further comprising specifying, from the plurality of color centers, a color center that satisfies a predetermined condition related to light emission characteristics before the acquiring the optical circuit. ### Claim 13 (depends on 11) The method for manufacturing an optical circuit according to claim 11, further comprising coupling a third optical waveguide that includes a material having a refractive index lower than a refractive index of diamond to the first optical waveguide. ### Claim 14 (depends on 11) The manufacturing method according to claim 11, wherein the impurities are implanted into the first member via a resist that covers a planned formation position of the first optical waveguide of the diamond. ### Claim 15 (depends on 13) The manufacturing method according to claim 13, wherein the optical circuit that includes the first optical waveguide and the second optical waveguides is acquired from a diamond layer of the first member in which the diamond layer and a low refractive index material layer that includes a material having a refractive index lower than the refractive index of diamond are laminated, and the third optical waveguide is acquired from the low refractive index material layer. ### Claim 16 A quantum operation device comprising: an optical circuit that includes a color center; a light source for excitation of the color center; and a photodetector that detects light emitted from the color center, wherein the optical circuit includes: a first optical waveguide that extends in a first direction and uses diamond as a material; a plurality of second optical waveguides each of which uses diamond as a material, includes a color center, is coupled to the first optical waveguide, and extends in a direction different from the first direction; and a third optical waveguide that includes a material having a refractive index lower than a refractive index of diamond, the third optical wave guide being coupled to the first optical waveguide.