# US 12,222,541 B2 · Optical fiber bundle structure, optical connector, optical fiber connection structure, and method of manufacturing optical fiber bundle structure

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- Number: US 12,222,541 B2
- Document ID: US12222541B2
- Status: Granted
- Kind: B2
- Application number: 18/410,522
- Filed: 2024-01-11
- Published: 2024-05-09
- Granted: 2025-02-11
- Earliest claimed: 2019-03-27
- Assignees: Furukawa Electric Co., Ltd.
- Applicants: Furukawa Electric Co., Ltd.
- Inventors: Kohei Kawasaki; Ryuichi Sugizaki; Masayoshi Tsukamoto; Masanori Takahashi; Shigehiro Takasaka; Koichi Maeda
- Web page: https://patentgrep.com/patent/US12222541B2

## CPC

- G02B 6/04: formed by bundles of fibres (G02B6/24 takes precedence)
- C03C 25/106: Single coatings
- C03C 25/26: Macromolecular compounds or prepolymers
- G02B 6/02042: {Multicore optical fibres}
- G02B 6/3664: {2D cross sectional arrangements of the fibres}
- G02B 6/368: {with pitch conversion between input and output plane, e.g. for increasing packing density}
- G02B 6/403: {of the ferrule type, connecting a pair of ferrules}
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- C03C: CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS

## Abstract

An optical fiber bundle structure includes: plural optical fiber core wires; a crossing preventing member; and a grasping member. Further, the crossing preventing member has slits and the widths of the slits positioned at the respective sides are each equal to or larger than a difference between: a length of one side of a polygon circumscribing the plural optical fiber core wires at a hindmost end portion of the slits at the trailing end; and a length of one side of a polygon circumscribing the plural optical fiber core wires at the leading end.

## Claims

### Claim 1

An optical fiber bundle structure, comprising:
plural optical fiber core wires;
a crossing preventing member having the plural optical fiber core wires inserted through the crossing preventing member along a longitudinal direction; and
a grasping member that applies a grasping force to the crossing preventing member, wherein
the plural optical fiber core wires have, in order from a leading end of the plural optical fiber core wires, a glass fiber portion, and a resin coated portion having resin coated on glass fibers,
the glass fiber portion has, in order from a leading end of the glass fiber portion, a small diameter portion, a tapered portion, and a large diameter portion,
the crossing preventing member has slits formed therein, the slits each having a width with a width's center at a point equally dividing one of sides of an approximate polygon circumscribing the plural optical fiber core wires, by a number of the optical fiber core wires that are in contact with that side in a cross section of the crossing preventing member, the cross section being orthogonal to the longitudinal direction, the slits extending from a leading end of the crossing preventing member to a midway point closer to a trailing end of the crossing preventing member,
each vertex of the approximate polygon circumscribing the plural optical fiber core wires has a curved shape, and
the sum of the widths of the slits positioned at the respective sides is equal to or larger than a difference between: a length of a shortest perimeter surrounding the plural optical fiber core wires at a hindmost end portion of the slits at the trailing end; and a length of a shortest perimeter surrounding the plural optical fiber core wires at the leading end.

### Claim 2 (depends on 1)

The optical fiber bundle structure according to claim 1, wherein the grasping member is a ring to be fitted closer to the leading end of the crossing preventing member.

### Claim 3 (depends on 1)

The optical fiber bundle structure according to claim 1, wherein the plural optical fiber core wires are provided in a square arrangement at the small diameter portion.

### Claim 4 (depends on 3)

The optical fiber bundle structure according to claim 3, wherein a number of the plural optical fiber core wires is four or nine.

### Claim 5 (depends on 1)

The optical fiber bundle structure according to claim 1, wherein the plural optical fiber core wires are provided in a hexagonal close-packed arrangement at the small diameter portion.

### Claim 6 (depends on 5)

The optical fiber bundle structure according to claim 5, wherein a number of the plural optical fiber core wires is seven or nineteen.

### Claim 7 (depends on 1)

An optical connector, comprising:
the optical fiber bundle structure according to claim 1, wherein
the grasping member is a ferrule having, formed therein, a hole portion that applies the grasping force to the crossing preventing member placed therein.

### Claim 8 (depends on 1)

An optical fiber connection structure, comprising:
the optical fiber bundle structure according to claim 1; and
a multi-core fiber having: plural core portions connected to cores of the plural optical fiber core wires; and a cladding portion formed around the plural core portions.

### Claim 9 (depends on 1)

An optical fiber connection structure, comprising:
the optical fiber bundle structure according to claim 1; and
plural light receiving and emitting portions connected to cores of the plural optical fiber core wires.