# US 11,079,536 B2 · Suppressing surface modes in fibers

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

- Number: US 11,079,536 B2
- Document ID: US11079536B2
- Status: Granted
- Kind: B2
- Application number: 16/858,355
- Filed: 2020-04-24
- Published: 2020-08-13
- Granted: 2021-08-03
- Earliest claimed: 2017-10-11
- Assignees: OFS Fitel, LLC
- Applicants: Ofs Fitel, LLC
- Inventors: Tristan Kremp; Brian Mangan; Robert S. Windeler
- Web page: https://patentgrep.com/patent/US11079536B2

## CPC

- G02B 6/02328: {Hollow or gas filled core}
- C03B 37/01208: {for making preforms of microstructured, photonic crystal or holey optical fibres}
- C03B 37/0122: {for making preforms of photonic crystal, microstructured or holey optical fibres}
- C03B 37/02781: {Hollow fibres, e.g. holey fibres}
- G02B 6/02338: {Structured core, e.g. core contains more than one material, non-constant refractive index distribution in core, asymmetric or non-circular elements in core unit, multiple cores, insertions between core and clad}
- G02B 6/02357: {Property of longitudinal structures or background material varies radially and/or azimuthally in the cladding, e.g. size, spacing, periodicity, shape, refractive index, graded index, quasiperiodic, quasicrystals}
- G02B 6/0239: {Comprising means for varying the guiding properties, e.g. tuning means}
- C03B 2203/16: Hollow core
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- C03B: MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES

## Abstract

A hollow core fiber (HCF) has a cross section with a substantially-circular hollow core in a cladding lattice, an axial center and a reference direction that extends radially in one direction from the axial center. The HCF comprises modified holes that are located along linear paths that extend radially outward from the axial center. The modified holes, which are located at various radial distances from the axial center and at various azimuthal angles from the reference direction, have non-uniform modified properties. These non-uniform modified properties include radially-varying properties, azimuthally-varying properties, or a combination of radially-varying and azimuthally-varying properties.

## Claims

### Claim 1

An optical fiber having an axial cross section, the axial cross section having an axial center, the axial cross section further having a reference direction that extends radially in one direction from the axial center, the optical fiber comprising:
a hollow core located substantially at the axial center; and
a cladding matrix surrounding the hollow core, the cladding matrix comprising:
cladding holes having cladding-hole properties;
struts located between cladding holes, the struts having substantially uniform properties; and
n non-uniform modified holes disposed in the cladding matrix at various radial distances from the axial center, n being an integer multiple of 6, the non-uniform modified holes further being disposed in the cladding matrix at approximately sixty degree (60°) angle increments from the reference direction, wherein the non-uniform modified holes have modified properties that differ from the cladding-hole properties, and wherein at least one modified hole has at least one modified property that differs from that of a second modified hole.

### Claim 2 (depends on 1)

The optical fiber of claim 1, n being 6.

### Claim 3 (depends on 1)

The optical fiber of claim 1, n being 12.

### Claim 4 (depends on 1)

The optical fiber of claim 1, n being 18.

### Claim 5 (depends on 1)

The optical fiber of claim 1, further comprising a shunt core located in the cladding matrix.

### Claim 6 (depends on 1)

The optical fiber of claim 1, the modified holes being located along linear paths that extend radially outward from the axial center.

### Claim 7 (depends on 1)

The optical fiber of claim 1, wherein the non-uniform modified holes vary radially and do not vary azimuthally.

### Claim 8 (depends on 1)

The optical fiber of claim 1, wherein the non-uniform modified holes vary azimuthally and do not vary radially.

### Claim 9 (depends on 1)

The optical fiber of claim 1, wherein the non-uniform modified holes vary both radially and azimuthally.

### Claim 10

In a manufacturing process using an outer tube having a substantially circular axial cross section, the axial cross section having an axial center, the axial cross section further having a reference direction that extends radially in one direction from the axial center, a process comprising the steps of:
arranging capillary tubes in the outer tube to form a matrix having a hollow region at the axial center; and
positioning n non-uniform modified tubes among the capillary tubes, the non-uniform modified tubes having modified properties, n being an integer multiple of 6, the non-uniform modified tubes being positioned at various radial distances from the axial center, the non-uniform modified tubes further being positioned at approximately sixty degree (60°) angle increments from the reference direction, and wherein at least one modified hole has at least one modified property that differs from that of a second modified hole.

### Claim 11 (depends on 10)

The process of claim 10, each modified tube having its respective hole diameter, wall thickness, node glass area, surface roughness, material composition, dopant type, and dopant concentration.

### Claim 12 (depends on 10)

The process of claim 10, n being 6.

### Claim 13 (depends on 10)

The process of claim 10, n being 12.

### Claim 14 (depends on 10)

The process of claim 10, n being 18.

### Claim 15 (depends on 10)

The process of claim 10, wherein the non-uniform modified holes vary radially and do not vary azimuthally.

### Claim 16 (depends on 10)

The process of claim 10, wherein the non-uniform modified holes vary azimuthally and do not vary radially.

### Claim 17 (depends on 10)

The process of claim 10, wherein the non-uniform modified holes vary both radially and azimuthally.