Exposed core optical fibers, and method of making same
AssigneeAT&T Bell Laboratories
InventorsArthur Ashkin, Rogers H. Stolen
Life of this patent
Estimating the term…
Abstract
The invention provides a method for making an optical fiber with a uniformly thin section of cladding. A preform having a core and at least one cladding layer is first made. The preform is prepared by cutting the preform so that the core is close to the surface of the preform. An optical fiber is pulled from the cut preform so the core is close to the surface of the optical fiber. The fiber may have cladding further removed by etching. A material selective etch may be used to make a protruding core fiber. Etching may be done on the preform before pulling the fiber.
Claims16
A method for making an optical fiber comprising the steps of:
- (a) making a preform, the preform having a length, an axis, a core, at least one cladding layer surrounding the core, a major surface enveloping the core and the cladding layer, and, at any point along the length of the preform, a predetermined distance between the core and the major surface;
- (b) preparing said preform by removing a segment of said preform, thereby producing a first preform surface, extending generally lengthwise for at least part of the length of the prepared preform, with the distance between the core and the first surface at any point along the first surface being less than the predetermined distance at that point;
- and
- (c) drawing an optical fiber from said prepared preform using a draw tension selected to result in the optical fiber having a cross section that is of substantially the same shape as the cross section of the prepared preform.
A method for making an optical fiber comprising the steps of:
- (a) making a preform of substantially circular cross section, the preform having a length, a core and at least one cladding layer;
- (b) preparing said preform by removing a segment of said preform so that the cross section of the prepared preform has, over at least a portion of the length, a boundary comprising a substantially circular arc and a chord drawn between the endpoints of said arc, with the cross section containing the core;
- and
- (c) drawing an optical fiber from said prepared preform using a draw tension selected such that the optical fiber has a cross section that is of substantially the same shape as the cross section of the prepared preform.
A method for making an optical fiber comprising the steps of:
- (a) making a preform, the preform having a length, an axis, a core, at least one cladding layer surrounding the core, a major surface enveloping the core and the cladding layer, and, at any point along the length of the preform, a predetermined distance between the core and the major surface;
- (b) preparing said preform by removing a segment of said preform, thereby producing a first preform surface, extending generally lengthwise for at least part of the length of the prepared preform, with the distance between the core and the first surface at any point along the first surface being less than the predetermined distance at that point;
- and
- (c) drawing an optical fiber from said prepared preform;
- the method further comprising
- (d) contacting, prior to step (c), a part of the first surface with an etching medium, whereby at least one groove is etched into the prepared preform, the groove oriented substantially transversely to the axis of the prepared preform.
A method for making an optical fiber, the method comprising the steps of:
- (a) making a preform, the preform having a length, an axis, a core, at least one cladding layer surrounding the core, a major surface enveloping the core and the cladding layer, and, at any point along the length of the preform, a predetermined distance between the core and the major surface;
- (b) preparing the preform by removing a segment of the preform, thereby producing a first preform surface, extending generally lengthwise for at least part of the length of the prepared preform, with the distance between the core and the first surface at any point along the first surface being less than the predetermined distance at that point, the first surface being inclined with respect to the axis of the preform;
- and
- (c) drawing an optical fiber from the prepared preform.
An optical fiber comprising a core having a circumference and at least one cladding layer contactingly surrounding the core, at least a part of the optical fiber being an exposed core optical fiber wherein the cladding layer partially surrounds the core, and wherein in the exposed core part of the optical fiber the cladding layer has a cross section with an outer boundary comprising an arcuate first portion and two second portions, each second portion extending from an endpoint of the arcuate first portion substantially to the core, and wherein the exposed portion of the core extends above the second portions of the outer boundary of the cladding cross section.
Dependencies are inferred from the claim text.