Bridge fiber, combiner, and fiber laser device

Patent metadata

Field	Value
Publication number	US-10014648-B2
Application number	US-201514740590-A
Country	US
Kind code	B2
Filing date	Jun 16, 2015
Priority date	Dec 21, 2012
Publication date	Jul 3, 2018
Grant date	Jul 3, 2018

Abstract

A bridge fiber includes a core layer and an outer layer which has an index of refraction higher than that of the core layer and covers the outer peripheral surface of the core layer. The outer layer is surrounded by a substance such as the atmosphere having an index of refraction lower than an index of refraction n 2 of the outer layer. An area AR 1 of the outer layer at one end face of the bridge fiber is an area that is to be optically coupled to an end face of a core of each of a plurality of pumping light inputting optical fibers, while an area AR 2 of the core layer at another end face of the bridge fiber is an area that is to be optically coupled to an end face of a core of an amplification optical fiber.

First claim

What is claimed is:

1. A bridge fiber comprising:
a core layer; and
an outer layer which has an index of refraction higher than an index of refraction of the core layer and covers an outer peripheral surface of the core layer, wherein
the outer layer is covered with a layer having an index of refraction lower than the index of refraction of the outer layer,
an area of the outer layer at one end face of the bridge fiber is an area that is to be optically coupled to an end face of a core of each of a plurality of pumping light inputting optical fibers,
an area of the core layer at another end face of the bridge fiber is an area that is to be optically coupled to an end face of a core of an amplification optical fiber, and
the layer does not have a hole,
wherein an index of refraction of the layer is lower than the index of refraction of the core layer.

2. The bridge fiber according to claim 1 , wherein an outer diameter of the core layer at the other end face of the bridge fiber is larger than an outer diameter of a core of an optical fiber fused to the core layer.

3. The bridge fiber according to claim 1 , further comprising a tapered portion, a diameter of which decreases from a side corresponding to the one end face of the bridge fiber toward a side corresponding to the other end face of the bridge fiber.

4. A combiner comprising:
a plurality of pumping light inputting optical fibers; and
a bridge fiber including:
a core layer; and
an outer layer which has an index of refraction higher than an index of refraction of the core layer and covers an outer peripheral surface of the core layer, wherein

the outer layer is covered with a layer having an index of refraction lower than the index of refraction of the outer layer,
an area of the outer layer at one end face of the bridge fiber is optically coupled to an end face of each of the plurality of pumping light inputting optical fibers,
an area of the core layer at another end face of the bridge fiber is an area that is to be optically coupled to an end face of a core of an amplification optical fiber,
the layer does not have a hole, and
wherein an index of refraction of the layer is lower than the index of refraction of the core layer.

5. A fiber laser device comprising:
a plurality of pumping light inputting optical fibers;
an amplification optical fiber;
a bridge fiber including:
a core layer; and
an outer layer which has an index of refraction higher than an index of refraction of the core layer and covers an outer peripheral surface of the core layer; and

a pair of mirrors which is disposed at a predetermined distance from each other in the amplification optical fiber, wherein
the outer layer is covered with a layer having an index of refraction lower than the index of refraction of the outer layer,
an area of the outer layer at one end face of the bridge fiber is optically coupled to an end face of each of the plurality of pumping light inputting optical fibers,
an area of the core layer at another end face of the bridge fiber is optically coupled to an end face of a core of the amplification optical fiber,
the layer does not have a hole, and
wherein an index of refraction of the layer is lower than the index of refraction of the core layer.

6. The bridge fiber according to claim 1 , wherein an outer diameter of the core layer at the other end face of the bridge fiber is larger than an outer diameter of a core of an optical fiber fused to the core layer.

7. The bridge fiber according to claim 1 , further comprising a tapered portion, a diameter of which decreases from a side corresponding to the one end face of the bridge fiber toward a side corresponding to the other end face of the bridge fiber.

8. The bridge fiber according to claim 2 , further comprising a tapered portion, a diameter of which decreases from a side corresponding to the one end face of the bridge fiber toward a side corresponding to the other end face of the bridge fiber.

9. The bridge fiber according to claim 6 , further comprising a tapered portion, a diameter of which decreases from a side corresponding to the one end face of the bridge fiber toward a side corresponding to the other end face of the bridge fiber.

10. The bridge fiber according to claim 1 , wherein the layer is an outermost layer.

11. The combiner according to claim 4 , wherein the layer is an outermost layer.

12. The fiber laser device according to claim 5 , wherein the layer is an outermost layer.

Assignees

• Fujikura Ltd

Inventors

• Kashiwagi Masahiro

Classifications

• H01S3/06745

  Tapering of the fibre, core or active region · CPC title

• H01S3/06783 Primary

  Amplifying coupler · CPC title

• G02B6/2821

  using lateral coupling between contiguous fibres to split or combine optical signals · CPC title

• H01S3/0675

  Resonators including a grating structure, e.g. distributed Bragg reflectors [DBR] or distributed feedback [DFB] fibre lasers · CPC title

• G02B6/2852

  using tapping light guides arranged sidewardly, e.g. in a non-parallel relationship with respect to the bus light guides (light extraction or launching through cladding, with or without surface discontinuities, bent structures) · CPC title