US 4,632,513 AGranted

Method of making a polarization-insensitive, evanescent-wave, fused coupler with minimal environmental sensitivity

AssigneeGould Inc.

InventorsDavid W. Stowe, Paul M. Kopera

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Abstract

An optical coupler and method of making same is described. The coupling ratio of the coupler is polarization-insensitive. The optical coupler described herein is made from single-mode optical fibers. Each optical fiber has a length of nearly exposed core which is fused to the exposed core of the other optical fiber while the fibers are maintained in parallel juxtaposition with one another without twisting. By creating a fused core coupler from single-mode optical fibers in which the cores are in parallel juxtaposition with one another, the coupling ratio of the subject invention does not change with changes in polarization of light passing through each single-mode fiber and, thus, is polarization insensitive.

Claims18

Dependent claims

A method of making a polarization-insensitive optical coupler comprising the steps of:

(a) etching first and second longitudinal segments of first and second single-mode optical fibers so that each fiber has an outer cladding having a low index of refraction relative to the index of refraction of a nearly exposed core of each of the first and second single-mode optical fibers;
(b) maintaining the first and second single-mode optical fibers in parallel juxtaposition with one another along a portion of each of the first and second longitudinal segment, said maintaining step comprising the substeps of:
(b1) wrapping portions of the first and second longitudinal segments with a material which will not substantially deform the nearly exposed cores of the first and second single-mode optical fibers;
(b2) gluing the nearly exposed cores of the first and second single-mode optical fibers together with glue while the nearly exposed cores are wrapped;
(b3) curing the glue;
and
(b4) unwrapping the nearly exposed cores;
(c) fusing together the portions of the first and second longitudinal segments maintained in parallel juxtaposition to form a coupling region;
and
(d) rigidly encapsulating the nearly exposed cores of the first and second single-mode optical fibers while maintaining the parallel juxtaposition of the first and second longitudinal segments.

7 more elements

A method of making a polarization-insensitive optical coupler comprising the steps of:

(a) etching first and second longitudinal segments of first and second single-mode optical fibers so that each fiber has an outer cladding have a low index of refraction relative to the index of refraction of a nearly exposed core of each of the first and second single-mode optical fibers;
(b) maintaining the first and second single-mode optical fibers in parallel juxtaposition with one another along a portion of each of the first and second longitudinal segments while placing the first and second longitudinal segments under axial tension;
(c) fusing the parallel juxtaposition portions of the first and second longitudinal segments together while the first and second longitudinal segments are maintained in parallel juxtaposition and remain under axial tension, so that a coupling region is formed.

A method of making a polarization-insensitive optical coupler comprising the steps of:

(a) etching first and second longitudinal segments of first and second single-mode optical fibers so that each fiber has an outer cladding having a low index of refraction relative to the index of refraction of a nearly exposed core of each of the first and second single-mode optical fibers;
(b) maintaining the first and second single-mode optical fibers in parallel juxtaposition with one another along a portion of each of the first and second longitudinal segments, said maintaining step including the substeps of:
(b1) wrapping portions of the first and second longitudinal segments with a material which will not substantially deform the nearly exposed cores of the first and second single-mode optical fibers;
(b2) bonding the nearly exposed cores of the first and second single-mode optical fibers together while the nearly exposed cores of the first and second single-mode optical fibers are wrapped;
and
(b3) unwrapping the nearly exposed cores of the first and second single-mode optical fibers;
and
(c) fusing the parallel juxtaposition portions of the first and second longitudinal segments together to form a coupling region.

5 more elements

Dependencies are inferred from the claim text.

Facts

Application: 06/705,044Filed 25 Feb 1985 · continuation
Priority: 26 May 1983
Granted: 30 Dec 1986
Term ends: Not estimatedThe source records don’t support an estimate.

Classification4 codes

G02B 6/2835
Using lateral coupling between contiguous fibres to split or combine optical signals: formed or shaped by thermal treatment, e.g. couplers
G02B 6/245
Coupling light guides: removing protective coverings of light guides before coupling
G02B 6/2843
Using lateral coupling between contiguous fibres to split or combine optical signals: the couplers having polarisation maintaining or holding…
G02B
Optical elements, systems or apparatus