US 6,208,781 B1Granted

Fiber optic transmission system for high power laser

AssigneeCeramOptec Industries, Inc.

InventorsWolfgang Neuberger, Alexander Kharschak

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Abstract

A fiber optic transmission system for high laser power transmission is described. A micro-structure, whose pre-determined features are characterized by a preferred shape, depth, and peak-to-peak distance, is introduced into an input end surface of an optical fiber. Such micro-structure reduces Fresnel reflection at the modified optical fiber end surface improving the damage threshold at the surface. Micro-structuring of the optical fiber output end surface in a similar fashion further enhances transmission of high laser powers. A method is disclosed where the optical fiber end surfaces are structured into a pre-determined micro-structure by a suitable stamp. The micro-structure increases the damage threshold of each optical fiber end surface, raising it closer to the theoretical damage threshold of the material within the fiber and thereby increases transmission of high laser power density that is available at a work or treatment site.

Claims3

Dependent claims

A fiber optic transmission system for high laser power transmission comprising:

at least one optical fiber having a core, a cladding and a cross sectional area, and having an input end and an output end, and each end having an end surface and a cross sectional area;
said at least one optical fiber consisting of an optical material which is transparent over a spectral region including wavelengths emitted by a chosen laser;
wherein said optical material of said optical fiber is substantially silica;
at least said input end being thermally deformed and having an expanded cross sectional area compared to said cross sectional area of said optical fiber;
at least said input end further having a micro-structured end surface whose features are pre-determined for a pre-selected operating wavelength of said chosen laser;
wherein said end surface of said thermally deformed input end has been polished flat perpendicular to a long axis of said optical fiber and presents an optimally sized flat surface for accepting output from a laser source;
said features being characterized by a preferred depth, a peak to peak distance, and a shape;
and
said preferred depth and said peak to peak distances on said micro-structured end surface being smaller than said pre-selected operating wavelength of said chosen laser.

6 more elements

Dependencies are inferred from the claim text.