Spun round core fiber

Patent metadata

Field	Value
Publication number	US-9784913-B2
Application number	US-201515115392-A
Country	US
Kind code	B2
Filing date	Jan 29, 2015
Priority date	Jan 30, 2014
Publication date	Oct 10, 2017
Grant date	Oct 10, 2017

Abstract

Optical waveguide cores having refractive index profiles that vary angularly about a propagation axis of the core can provide single-mode operation with larger core diameters than conventional waveguides. An optical waveguide includes a core that extends along a propagation axis and has a refractive index profile that varies angularly about the propagation axis. The optical waveguide also includes a cladding disposed about the core and extending along the propagation axis. The refractive index profile of the core varies angularly along a length of the propagation axis.

First claim

What is claimed is:

1. A method of making a core rod preform, comprising:
situating one or more silica rods having a first index of refraction in a silica tube;
situating one or more silica rods having a second index of refraction in the silica tube;
collapsing the silica tube to form a core rod preform; wherein
the core rod preform has a refractive index profile that varies angularly about a longitudinal axis of the preform.

2. A method, comprising:
situating a core rod within a cladding tube to obtain an optical fiber preform, the core rod having a refractive index profile that varies angularly about a longitudinal axis of the core rod; and
drawing the optical fiber preform to create an optical fiber; wherein
the optical fiber preform is rotated while being drawn such that the refractive index profile of a core of the resultant optical fiber varies angularly along the longitudinal axis of the core.

3. The method of claim 2 , wherein the angular variation of the refractive index profile of the core is periodic along the longitudinal axis of the core.

4. The method of claim 2 , wherein the angular variation of the refractive index profile of the core is aperiodic along the longitudinal axis of the core.

5. An optical waveguide, comprising:
a core that extends along a propagation axis, the core having a refractive index profile that varies angularly about the propagation axis; and
a cladding disposed about the core and extending along the propagation axis, the cladding having a refractive index profile that varies angularly about the propagation axis;
wherein the refractive index profile of the cladding and the refractive index profile of the core vary angularly along the propagation axis;
wherein the cladding further comprises one or more mode-discriminating regions, and the one or more mode-discriminating regions are situated a radial distance from the core, the radial distance corresponding to a wavelength of optical radiation to be propagated through the optical waveguide.

6. The optical waveguide of claim 5 , wherein:
the core has a round cross-section; and
the cladding has a polygonal cross-section.

Assignees

• Nlight Inc

Inventors

• Koponen Joona
• Ye Changgeng
• Kimmelma Ossi

Classifications

• G02B6/02338

  Structured core, e.g. core contains more than one material, non-constant refractive index distribution in core, asymmetric or non-circular elements in core unit, multiple cores, insertions between core and clad · CPC title

• G02B6/0286 Primary

  Combination of graded index in the central core segment and a graded index layer external to the central core segment (G02B6/0288 takes precedence) · CPC title

• C03B2205/07

  Rotating the preform about its longitudinal axis · CPC title

• C03B2203/34

  Plural core other than bundles, e.g. double core · CPC title

• G02B6/02

  Optical fibres with cladding {with or without a coating} · CPC title