# US 2025/0093574 A1 · Optical fiber with reduced attenuation

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- Number: US 2025/0093574 A1
- Document ID: US20250093574A1
- Status: Published application
- Kind: A1
- Application number: 18/809,457
- Filed: 2024-08-20
- Published: 2025-03-20
- Earliest claimed: 2023-09-18
- Assignees: Corning Incorporated
- Applicants: Corning Incorporated
- Inventors: Rostislav Radiyevich Khrapko; Ming-Jun Li; Stephan Lvovich Logunov; Craig Daniel Nie
- Web page: https://patentgrep.com/patent/US20250093574A1

## CPC

- G02B 6/02009: {Large effective area or mode field radius, e.g. to reduce nonlinear effects in single mode fibres}
- G02B 6/0365: {arranged - - +}
- G02B 6/03627: {arranged - +}
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS

## Abstract

An optical fiber that includes a silica core and a cladding surrounding the core is disclosed, the optical fiber having a low attenuation. In embodiments, the optical fiber has an attenuation at 1550 nm of about 0.1420 dB/km. Furthermore, the diameter of the core may be larger than a fundamental mode field diameter of the optical fiber at a wavelength of 1550 nm. In embodiments, the core is doped with an alkali dopant.

## Claims

### Claim 1

An optical fiber comprising:
a core comprised of silica and cladding surrounding the core,
wherein the optical fiber has an attenuation at 1550 nm of about 0.1420 dB/km or less.

### Claim 2 (depends on 1)

The optical fiber of claim 1, wherein the attenuation of the optical fiber at 1550 nm is about 0.1410 dB/km or less.

### Claim 3 (depends on 1)

The optical fiber of claim 1, wherein the optical fiber has the attenuation at 1550 nm of about 0.1420 dB/km or less over at least 22 km of continuous optical fiber.

### Claim 4 (depends on 1)

The optical fiber of claim 1, wherein a diameter of the core is larger than a fundamental mode field diameter of the optical fiber at a wavelength of 1550 nm.

### Claim 5 (depends on 4)

The optical fiber of claim 4, wherein a ratio of the core diameter to the fundamental mode field diameter is about 1.05 or greater.

### Claim 6 (depends on 5)

The optical fiber of claim 5, wherein the ratio is about from about 1.05 to about 1.20.

### Claim 7 (depends on 5)

The optical fiber of claim 5, wherein the ratio is from about 1.10 to about 1.20.

### Claim 8 (depends on 1)

The optical fiber of claim 1, wherein a diameter of the core is in a range from about 12 microns to about 25 microns.

### Claim 9 (depends on 1)

The optical fiber of claim 1, wherein a fundamental mode field diameter of the optical fiber at 1550 nm is in a range from about 11 microns to about 16 microns.

### Claim 10 (depends on 1)

The optical fiber of claim 1, wherein the cable cutoff wavelength of the optical fiber is from about 1500 nm to about 3000 nm.

### Claim 11 (depends on 1)

The optical fiber of claim 1, wherein the total Rayleigh scattering loss of the optical fiber at 1550 nm is about 0.135 dB/km or less.

### Claim 12 (depends on 1)

The optical fiber of claim 1, wherein the small angle scattering loss of the optical fiber at 1550 nm is about 0.004 dB/km or less.

### Claim 13 (depends on 1)

The optical fiber of claim 1, wherein the fiber is a single mode fiber.

### Claim 14 (depends on 1)

The optical fiber of claim 1, wherein the fiber is a quasi-single mode fiber.

### Claim 15

An optical fiber comprising:
a core comprised of silica doped with an alkali dopant; and
cladding surrounding the core,
wherein a diameter of the core is larger than a fundamental mode field diameter of the optical fiber at a wavelength of 1550 nm, and
wherein the optical fiber has an attenuation at 1550 nm of about 0.1460 dB/km or less.

### Claim 16 (depends on 15)

The optical fiber of claim 15, wherein the attenuation of the optical fiber at 1550 nm is about 0.1450 dB/km or less.

### Claim 17 (depends on 15)

The optical fiber of claim 15, wherein the attenuation of the optical fiber at 1550 nm is about 0.1420 dB/km or less.

### Claim 18 (depends on 15)

The optical fiber of claim 15, wherein the alkali dopant comprises potassium.

### Claim 19 (depends on 18)

The optical fiber of claim 18, wherein the alkali dopant comprises potassium at a concentration greater than or equal to about 10 ppm.

### Claim 20 (depends on 19)

The optical fiber of claim 19, wherein the cladding comprise a fluorine dopant.