# US 12,111,522 B2 · Isolator, light source apparatus, optical transceiver, optical switch, optical amplifier, and data center

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 12,111,522 B2
- Document ID: US12111522B2
- Status: Granted
- Kind: B2
- Application number: 17/296,418
- Filed: 2019-11-01
- Published: 2022-01-27
- Granted: 2024-10-08
- Earliest claimed: 2018-11-28
- Assignees: KYOCERA Corporation
- Applicants: KYOCERA Corporation
- Inventors: Naoki Matsui; Hiromichi Yoshikawa; Tomoya Sugita
- Web page: https://patentgrep.com/patent/US12111522B2

## CPC

- G02F 1/0955: {used as non-reciprocal devices, e.g. optical isolators, circulators}
- G02B 6/125: Bends, branchings or intersections
- G02B 6/2746: {comprising non-reciprocal devices, e.g. isolators, FRM, circulators, quasi-isolators (magneto-optic non-reciprocal devices G02F1/093)}
- G02B 6/29338: {Loop resonators}
- G02B 27/281: {used for attenuating light intensity, e.g. comprising rotatable polarising elements}
- H04B 10/40: Transceivers
- G02B 6/126: using polarisation effects {(G02B6/1226 takes precedence)}
- G02B 2006/12157: {Isolator}
- H04B 10/50: Transmitters
- H04B 10/802: {for isolation, e.g. using optocouplers}
- 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
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- H04B: TRANSMISSION

## Abstract

An isolator includes a first waveguide with a linear shape and a second waveguide with an annular shape on a substrate including a substrate surface, the first waveguide being positioned along the substrate surface. The first waveguide and the second waveguide each include a core and a cladding. The first waveguide includes a first end, a second end, and a port at each of the first end and the second end for input and output of electromagnetic waves. The core of the second waveguide includes a non-reciprocal member in at least a portion of a cross-section intersecting a direction in which the second waveguide extends.

## Claims

### Claim 1

An isolator comprising:
a first waveguide with a linear shape positioned on a substrate surface of a substrate, and a second waveguide with an annular shape positioned adjacent the first waveguide, wherein
the first waveguide and the second waveguide each include a core and a cladding,
the first waveguide and the second waveguide each are positioned along each other at least at a portion thereof in a direction of extension as a parallel waveguide,
the second waveguide includes a straight part, at least a portion of the straight part being parallel with the first waveguide as the parallel waveguide,
the first waveguide includes a first end, a second end, and a port at each of the first end and the second end for input and output of electromagnetic waves, and
the core of the second waveguide includes, in at least a portion of parts being the parallel waveguide, a non-reciprocal member in at least a portion of a cross-section intersecting a direction in which the second waveguide extends.

### Claim 2 (depends on 1)

The isolator of claim 1, wherein the second waveguide is optically connected without interruption.

### Claim 3 (depends on 1)

The isolator of claim 1, wherein the first waveguide and the second waveguide are positioned side by side in parallel on the substrate surface.

### Claim 4 (depends on 1)

The isolator of claim 1, wherein the first waveguide and the second waveguide are positioned to overlap each other in a plan view of the substrate surface.

### Claim 5 (depends on 1)

The isolator of claim 1, wherein a polarization direction of electromagnetic waves inputted to the port at the first end is parallel to the substrate surface.

### Claim 6 (depends on 1)

The isolator of claim 1, wherein
the non-reciprocal member includes a non-reciprocal material at a predetermined concentration, and
the predetermined concentration changes in at least a portion of the non-reciprocal member as viewed from a direction along a polarization direction of electromagnetic waves inputted to the port at the first end.

### Claim 7 (depends on 1)

The isolator of claim 1, wherein the electromagnetic waves inputted to the first end and the second end are propagated in a single mode.

### Claim 8 (depends on 1)

The isolator of claim 1, wherein a length of the second waveguide is an odd multiple of a coupling length of the first waveguide and the second waveguide with respect to electromagnetic waves propagating from the second end to the first end.

### Claim 9 (depends on 1)

The isolator of claim 1, wherein L representing a length of the second waveguide is calculated by
L=mλ0/2|(neven−nodd)|
where neven represents an even mode refractive index and nodd represents an odd mode refractive index with respect to electromagnetic waves propagating from the second end to the first end in a coupling between the first waveguide and the second waveguide, m is an odd number, and λ0 is a wavelength in a vacuum.

### Claim 10 (depends on 1)

The isolator of claim 1, wherein a length of the second waveguide is an even multiple of a coupling length of the first waveguide and the second waveguide with respect to electromagnetic waves propagating from the first end to the second end.

### Claim 11 (depends on 1)

The isolator of claim 1, wherein
the core of the first waveguide includes a first surface positioned on a substrate side of the first waveguide, a second surface positioned on an opposite side from the first surface, and a plurality of holes passing through from the first surface to the second surface, and
the plurality of holes are side by side in a direction in which the core of the first waveguide extends.

### Claim 12 (depends on 1)

The isolator of claim 1, further comprising
a connection waveguide configured to connect to the port, wherein
a relative permittivity of a core of the connection waveguide is substantially equal to a relative permittivity of at least a portion of the core of the first waveguide, and
a width of the core of the connection waveguide as viewed from a direction that lies along the substrate surface and intersects a direction in which the first waveguide extends is substantially equal to a width of the core of the first waveguide.

### Claim 13

An isolator comprising:
a first waveguide including a first end, a second end, and a port at each of the first end and the second end for input and output of electromagnetic waves; and
a second waveguide with an annular shape positioned along the first waveguide, wherein
the first waveguide and the second waveguide each are positioned along each other at least at a portion thereof in a direction of extension as a parallel waveguide,
the second waveguide includes a straight part, at least a portion of the straight part being parallel with the first waveguide as the parallel waveguide,
the first waveguide and the second waveguide are coupled so that, at any operating frequency of the isolator, a coupling coefficient when electromagnetic waves inputted from the second end propagate towards the first end is greater than a coupling coefficient when electromagnetic waves inputted from the first end propagate towards the second end, and
a core of the second waveguide includes, in at least a portion of parts being the parallel waveguide, a non-reciprocal member in at least a portion of a cross-section intersecting a direction in which the second waveguide extends.

### Claim 14 (depends on 13)

The isolator of claim 13, wherein a length over which the first waveguide and the second waveguide lie along each other is substantially equal to a coupling length of the first waveguide and the second waveguide with respect to electromagnetic waves propagating from the second end towards the first end.

### Claim 15 (depends on 13)

The isolator of claim 13, wherein the first waveguide includes a matching adjustment circuit at a portion of the first waveguide where the first waveguide couples with the second waveguide.

### Claim 16 (depends on 1)

A light source apparatus comprising:
the isolator of claim 1; and
a light source, wherein
the light source optically connects to the port.

### Claim 17 (depends on 1)

An optical transceiver comprising:
a light source apparatus including
the isolator of claim 1; and
a light source configured to connect optically to the port; and
a light modulation function that modulates the light source.

### Claim 18 (depends on 1)

An optical switch comprising the isolator of claim 1.

### Claim 19 (depends on 1)

An optical amplifier comprising the isolator of claim 1.

### Claim 20 (depends on 1)

A data center configured to communicate via a device comprising the isolator of claim 1.