# US 2025/0147262 A1 · Feedthrough and method for manufacturing feedthrough

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- Number: US 2025/0147262 A1
- Document ID: US20250147262A1
- Status: Published application
- Kind: A1
- Application number: 18/923,864
- Filed: 2024-10-23
- Published: 2025-05-08
- Earliest claimed: 2023-11-07
- Assignees: NEC Corporation
- Applicants: NEC Corporation
- Inventors: Toshihide NAGASAWA
- Web page: https://patentgrep.com/patent/US20250147262A1

## CPC

- G02B 6/44775: {Cable seals e.g. feed-through (cable seals integrated to the box seals G02B6/4444; pulling eyes G02B6/44465)}
- G02B 6/4479: {Manufacturing methods of optical cables}
- G02B 6/4248: {Feed-through connections for the hermetical passage of fibres through a package wall (see provisionally also G02B6/4428)}
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS

## Abstract

To provide a feedthrough and a method for manufacturing the feedthrough that make it possible to achieve high reliability and reduce optical loss of an optical fiber. The feedthrough includes: a sleeve including an upper sleeve portion, a sleeve central portion, and a sleeve lower portion; a guide fitted to at least an inner peripheral surface of the sleeve central portion; an optical fiber inserted through a through hole formed in the sleeve; and a sealing material being formed between the sleeve upper portion and the guide and hermetically sealing a part of the optical fiber to a sealing groove communicating with the through hole. In the sleeve, a thermal conductivity of the sleeve lower portion is lower than a thermal conductivity of the sleeve upper portion.

## Claims

### Claim 1

A feedthrough comprising:
a sleeve including a sleeve upper portion, a sleeve central portion, and a sleeve lower portion;
a guide fitted to at least an inner peripheral surface of the sleeve central portion;
an optical fiber inserted through a through hole formed in the sleeve;
and a sealing material being formed between the sleeve upper portion and the guide and hermetically sealing a part of the optical fiber in a sealing groove communicating with the through hole,
Wherein, in the sleeve, a thermal conductivity of the sleeve lower portion is lower than a thermal conductivity of the sleeve upper portion.

### Claim 2 (depends on 1)

The feedthrough according to claim 1, wherein the sleeve lower portion has a thickness greater than a thickness of the sleeve upper portion in such a way as to expand radially outward.

### Claim 3 (depends on 1)

The feedthrough according to claim 1, wherein a heat dissipation member is attached to at least one of an inner peripheral surface and an outer peripheral surface of the sleeve lower portion.

### Claim 4 (depends on 1)

The feedthrough according to claim 1, wherein the sleeve lower portion has a fin shape.

### Claim 5 (depends on 1)

The feedthrough according to claim 1, wherein a heat adjustment groove recessed from an outer peripheral surface toward an inner side in a radial direction is formed in the sleeve central portion.

### Claim 6 (depends on 1)

The feedthrough according to claim 1, wherein a heat adjustment groove recessed from an upper end surface toward a lower side is formed in a guide upper portion of the guide.

### Claim 7 (depends on 1)

The feedthrough according to claim 1, wherein a submarine cable using the optical fiber as a transmission line is connected to a submarine repeater.

### Claim 8

A method for manufacturing a feedthrough, comprising,
by means of a heat-melted and solidified sealing material, hermetically sealing a part of an optical fiber inserted into a through hole formed in a sleeve including a sleeve upper portion, a sleeve central portion, and a sleeve lower portion to a sealing groove being formed between the sleeve upper portion and a guide fitted to at least an inner peripheral surface of the sleeve central portion and communicating with the through hole,
wherein, in the sleeve, a thermal conductivity of the sleeve lower portion is lower than a thermal conductivity of the sleeve upper portion.