# US 2025/0093583 A1 · Isolator, optical switch, optical transmitter and receiver, data center, and isolator manufacturing method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2025/0093583 A1 - Document ID: US20250093583A1 - Status: Published application - Kind: A1 - Application number: 18/571,917 - Filed: 2023-08-07 - Published: 2025-03-20 - Earliest claimed: 2023-06-01 - Assignees: KYOCERA Corporation - Applicants: KYOCERA Corporation - Inventors: Tomoya SUGITA; Reona MOTOJI; Dan MAEDA - Web page: https://patentgrep.com/patent/US20250093583A1 ## CPC - G02B 6/2746: {comprising non-reciprocal devices, e.g. isolators, FRM, circulators, quasi-isolators (magneto-optic non-reciprocal devices G02F1/093)} - G02B 6/264: {with optical elements between opposed fibre ends which perform a function other than beam splitting (having lens focusing means G02B6/32; utilising prism or grating G02B6/34)} - G02F 1/0955: {used as non-reciprocal devices, e.g. optical isolators, circulators} - G02B 2006/12157: {Isolator} - G02B 2006/12159: {Interferometer} - 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 isolator includes a substrate, a waveguide, an insulating layer, and a non-reciprocity member. The insulating layer includes a recess. The recess overlaps at least part of the waveguide. The non-reciprocity member is positioned in the recess. The waveguide includes a first waveguide and a second waveguide. The recess includes a first recess and a second recess. The non-reciprocity member includes a first non-reciprocity member positioned in the first recess and a second non-reciprocity member positioned in the second recess. A propagation direction of the electromagnetic wave in a portion of the first waveguide, the portion overlapping the first non-reciprocity member, and a propagation direction of the electromagnetic wave in a portion of the second waveguide, the portion overlapping the second non-reciprocity member, are different from each other. ## Claims ### Claim 1 An isolator comprising: a substrate with a substrate surface; a first waveguide and a second waveguide each extending on the substrate surface and causing an electromagnetic wave in a TM mode to propagate therethrough along an extension direction; an insulating layer positioned on the substrate surface and surrounding at least part of each of the first waveguide and the second waveguide; and a first non-reciprocity member and a second non-reciprocity member, wherein the insulating layer has a surface positioned above an upper surface of the first waveguide and an upper surface of the second waveguide, the insulating layer including a first recess and a second recess, the first recess is defined by a bottom surface positioned lower than the surface of the insulating layer and by side surfaces positioned between the bottom surface and the surface of the insulating layer the first recess overlapping at least part of the first waveguide in a plan view of the substrate surface, the second recess is defined by a bottom surface positioned lower than the surface of the insulating layer and by side surfaces positioned between the bottom surface and the surface of the insulating layer the second recess overlapping at least part of the second waveguide in the plan view of the substrate surface, the first non-reciprocity member is positioned on the bottom surface of the first recess and overlaps at least part of the first waveguide in the plan view of the substrate surface, the second non-reciprocity member is positioned on the bottom surface of the second recess and overlaps at least part of the second waveguide in the plan view of the substrate surface, and a propagation direction of the electromagnetic wave in a portion of the first waveguide, the portion overlapping the first non-reciprocity member in the plan view of the substrate surface, and a propagation direction of the electromagnetic wave in a portion of the second waveguide, the portion overlapping the second non-reciprocity member in the plan view of the substrate surface, are different from each other. ### Claim 2 (depends on 1) The isolator according to claim 1, wherein at least part of the upper surface of the first waveguide is in contact with the first non-reciprocity member, and at least part of the upper surface of the second waveguide is in contact with the second non-reciprocity member. ### Claim 3 (depends on 1) The isolator according to claim 1, wherein a position of the bottom surface of the first recess in a direction vertical to the substrate surface is lower than a position of the upper surface of the first waveguide, and a position of the bottom surface of the second recess in the direction vertical to the substrate surface is lower than a position of the upper surface of the second waveguide. ### Claim 4 (depends on 1) The isolator according to claim 1, wherein the insulating layer is positioned between the upper surface of the first waveguide and the first non-reciprocity member, and the insulating layer is positioned between the upper surface of the second waveguide and the second non-reciprocity member. ### Claim 5 (depends on 4) The isolator according to claim 4, wherein a thickness of the insulating layer positioned between the upper surface of the first waveguide and the first non-reciprocity member and a thickness of the insulating layer positioned between the upper surface of the second waveguide and the second non-reciprocity member are respectively less than ½ of values resulting from subtracting heights of the first waveguide and the second waveguide in cross-sections thereof from mode field diameters for the first waveguide and the second waveguide in a direction vertical to the substrate surface. ### Claim 6 (depends on 1) The isolator according to claim 1, wherein a length of the first recess in a width direction of the first waveguide is longer than a crystal size of the first non-reciprocity member, and a length of the second recess in a width direction of the second waveguide is longer than a crystal size of the second non-reciprocity member. ### Claim 7 (depends on 1) The isolator according to claim 1, wherein the first non-reciprocity member and the second non-reciprocity member contain YIG (yttrium iron garnet). ### Claim 8 (depends on 1) The isolator according to claim 1, wherein, of the side surfaces defining the first recess, the side surfaces positioned at ends of the first waveguide in an extension direction thereof are inclined relative to a plane perpendicular to the extension direction of the first waveguide, and of the side surfaces defining the second recess, the side surfaces positioned at ends of the second waveguide in an extension direction thereof are inclined relative to the plane perpendicular to the extension direction of the second waveguide. ### Claim 9 (depends on 1) The isolator according to claim 1, wherein, of the side surfaces defining the first recess, the side surfaces positioned at ends of the first waveguide in an extension direction thereof are inclined toward an outer side of the first recess relative to the direction vertical to the substrate surface, and of the side surfaces defining the second recess, the side surfaces positioned at ends of the second waveguide in an extension direction thereof are inclined toward an outer side of the second recess relative to the direction vertical to the substrate surface. ### Claim 10 (depends on 1) The isolator according to claim 1, wherein the first waveguide and the second waveguide are positioned within a substantially circular region in the plan view of the substrate surface. ### Claim 11 (depends on 1) The isolator according to claim 1, wherein a distance through which the first waveguide overlaps the first non-reciprocity member and a distance through which the second waveguide overlaps the second non-reciprocity member are equal to each other. ### Claim 12 (depends on 1) The isolator according to claim 1, further comprising a heater arranged to control a temperature of each of the first waveguide and the second waveguide. ### Claim 13 (depends on 1) An optical switch comprising: the isolator according to claim 1. ### Claim 14 (depends on 1) An optical transmitter and receiver comprising: the isolator according to claim 1; and a light source optically connected to the isolator. ### Claim 15 (depends on 1) A data center configured to perform communication by a device comprising the isolator according to claim 1. ### Claim 16 An isolator manufacturing method comprising: forming, on a substrate, a first waveguide and a second waveguide through each of which an electromagnetic wave in a TM mode propagates; forming an insulating layer on the first waveguide and the second waveguide; etching the insulating layer and forming a first recess overlapping at least a portion of the first waveguide and a second recess overlapping at least a portion of the second waveguide such that a propagation direction of the electromagnetic wave in the portion of the first waveguide overlapping the first recess and a propagation direction of the electromagnetic wave in the portion of the second waveguide overlapping the second recess are different from each other; forming a first non-reciprocity member on a bottom surface of the first recess; forming a second non-reciprocity member on a bottom surface of the second recess; and irradiating the first non-reciprocity member and the second non-reciprocity member with laser light.