Bragg grating optical fiber
AssigneeCorning Incorporated
InventorsMara Bagnasco, Valeria Gusmeroli
Life of this patent
Estimating the term…
Abstract
The present invention provides an optical fiber providing high photosensitivity in the absence of hydrogen loading as well as a low numerical aperture. One aspect of the present invention relates to an optical fiber including a core, the core comprising silica doped with at least about 6 mol % germania and at least about 0.9 wt % fluorine; and a cladding surrounding the core. The optical fiber of the present invention is suitable for the production of fiber Bragg gratings.
Claims27
An optical fiber comprising a core comprising silica and a cladding surrounding the core characterized in that the core is doped with at least about 6 mol % germania and at least about 0.9 wt % fluorine.
The optical fiber of any one of the preceding claims, wherein the core is substantially devoid of boron.
The optical fiber of any one of the preceding claims, wherein the core includes no other dopants in substantial amounts.
The optical fiber of any one of the preceding claims, wherein the optical fiber has a numerical aperture of less than about 0.22 at 1550 nm.
The optical fiber of any one of the preceding claims, wherein the core exhibits an index change of at least about 5.5×10−4 at a wavelength of 1550 nm when exposed to a dose of radiation having a wavelength of 244 nm and an energy of 428 J through a phase mask yielding an interference pattern with a visibility of about 80%, said exposure being performed without hydrogen loading of the optical fiber.
The optical fiber of any one of the preceding claims wherein the core exhibits a ratio of index change at 1550 nm to numerical aperture of at least about 3.0×10−3, the index change being caused by an exposure in the absence of hydrogen loading to a dose of radiation having a wavelength of 244 nm and an energy of 428 J through a phase mask yielding an interference pattern with a visibility of about 80%.
A method of fabricating a fiber Bragg grating, the method comprising the steps of
- providing an optical fiber comprising
- a core, the core comprising silica doped with at least about 6 mol % germanium and at least about 0.9 wt % fluorine, and
- a cladding surrounding the core;
- and
- exposing a section of the optical fiber to patterned UV radiation, thereby writing the grating in the core of the fiber.
An optical fiber comprising
- A core, the core comprising silica doped with at least about 6 mol % germania and with fluorine;
- and
- a cladding surrounding the core, wherein the optical fiber has a numerical aperture of less than about 0.22 at 1550 nm.
Dependencies are inferred from the claim text.