Mode filter with refractive index modification

摘要

The invention relates to a mode filter for reducing higher-order modes, with an optical fiber (1), which has a core (2) and a cladding (3) surrounding the latter, wherein the cladding (3) and core (2) have refractive indices that differ from one another. In order to develop an alternative to the prior art, the mode filter according to the invention is designed in such a manner that the fiber (1) has, in a transition region (4) between core (2) and cladding (3), at least one local refractive index modification region (5) which is arranged in the radially outer region of the core (2) and extends into the region of the cladding (3).

主权项

1. A mode filter for reducing higher-order modes, the mode filter comprising:
an optical fiber having
a core having a core refractive index,a cladding surrounding the core and having a cladding refractive index, anda transition region between the core and the cladding, wherein the cladding refractive index is different from the core refractive index, wherein the optical fiber has in the transition region at least one local refractive index modification region arranged in a radially outer region of the core and extending into the cladding, and wherein the at least one local refractive index modification region comprises:
a first refractive index modification region touching the core only along a first tangential touching region, the first tangential touching region being along a first side of the core anda second refractive index modification region running parallel to the first refractive index modification region and touching the core only along a second tangential touching region, the second tangential touching region being along a second side of the core, the second side of the core being disposed opposite from the first side of the core.