Triple-sheathed monomode optical fiber

Patent metadata

Field	Value
Publication number	US-9256025-B2
Application number	US-201214113663-A
Country	US
Kind code	B2
Filing date	Apr 24, 2012
Priority date	Apr 26, 2011
Publication date	Feb 9, 2016
Grant date	Feb 9, 2016

Abstract

According to the invention, the intermediate sheath ( 13 ) is formed by assembling longitudinal elements ( 13 A) and includes: a first optical material, the refractive index of which differs from the refractive index of the monomode core by at most 10 −3 ; and a second optical material, the refractive index of which is lower than the refractive index of said monomode core and differs therefrom by at least 10 −3 .

First claim

The invention claimed is:

1. Monomode optical fiber comprising, from center to periphery:
a monomode core doped at least partly with a rare earth,
an optically inactive intermediate sheath,
a multimode pumping sheath, and
an outer sheath,
wherein the intermediate sheath is formed by an assembly of solid bars, and
said assembly of solid bars comprises first solid bars made of a first optical material with a refractive index that differs from the refractive index of said monomode core by at most 10.sup.-3, and second solid bars made of a second optical material with a refractive index that differs from the refractive index of said monomode core by at least 10.sup.-3.

2. Monomode optical fiber according to claim 1 , wherein
the refractive index of said first optical material is equal or as close as possible to the refractive index of said monomode core, and
intermediate sheath has an effective refractive index lower than the refractive index of the monomode core, the refractive index of said second optical material being much lower than the refractive index of said monomode core.

3. Monomode optical fiber according to claim 1 , wherein
the refractive index of said first optical material is equal or as close as possible to the refractive index of said monomode core, and
the intermediate sheath has an effective refractive index higher than the refractive index of the monomode core, the refractive index of said second optical material being much higher than the refractive index of said monomode core.

4. Monomode optical fiber according to claim 1 , wherein, in said assembly, said solid bars of the intermediate sheath are arranged in a matrix arrangement.

5. Monomode optical fiber according to claim 1 , wherein the solid bars of the intermediate sheath have a transverse dimension greater than the monomode emission wavelength of said monomode optical fiber by a factor of at least 10.

6. Monomode optical fiber according to claim 1 , wherein the solid bars of the intermediate sheath have a transverse dimension less than the monomode emission wavelength of said monomode optical fiber.

7. Monomode optical fiber according to claim 1 , wherein modal filtering means are arranged at the monomode core and/or the intermediate sheath.

8. Monomode optical fiber according to claim 1 , wherein the intermediate sheath has an effective refractive index that differs from the refractive index of the monomode core by 10.sup.-4 at most.

Assignees

• Roy Philippe
• Schuster Kay
• Grimm Stephan
• Centre Nat Rech Scient
• Univ Limoges

Inventors

• Roy Philippe
• Schuster Kay
• Grimm Stephan

Classifications

• H01S3/06733

  Fibre having more than one cladding · CPC title

• G02B6/02333

  Core having higher refractive index than cladding, e.g. solid core, effective index guiding · CPC title

• H01S3/06741

  Photonic crystal fibre, i.e. the fibre having a photonic bandgap · CPC title

• G02B6/02314

  Plurality of longitudinal structures extending along optical fibre axis, e.g. holes · CPC title

• G02B6/02357

  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 · CPC title