Ofs Fitel, LLC

Furukawa Electric North America, Inc.

Xinli Jiang

George Edward Oulundsen, Iii

Jinkee Kim

Durgesh Vaidya

David John DiGiovanni

Man Fei Yan

Yi Sun

Frank Vincent DiMarcello

Sandeep Prabhakar Pandit

Thierry Franck Taunay

George Oulundsen

George E Oulundsen

Danid John Digiovanni

Durgesh Shivram Vaidya

The specification describes multimode optical fibers with specific design parameters, i.e., controlled refractive index design ratios and dimensions, which render the optical fibers largely immune to moderately severe bends. The modal structure in the optical fibers is also largely unaffected by bending, thus leaving the optical fiber bandwidth essentially unimpaired. Bend performance results were established by DMD measurements of fibers wound on mandrels vs. measurements of fibers with no severe bends. Additional embodiments of the present invention describe an improved optical link when the inventive multimode fiber is connected to standard or conventional multimode fibers.

Bandwidth-maintaining multimode optical fibers

Apparatus and method of simultaneously measuring a parameter of a plurality of cores in at least one optical fiber. An input tester at a first end of the test fiber has a plurality of tester signal inputs with a geometry substantially matching at least a portion of the core geometry of the fiber. At least one test input signal source coupled to the plurality of tester signal inputs. A signal measuring device is alignable at a second end of the fiber to measure the output of the test input signal. The input tester may include a tapered multicore coupler or a laser having a shield with apertures disposable between the laser and the fiber. In the latter case, a lens may be disposed between the shield and the fiber to project light from the laser that passes through the apertures onto the end of the fiber.

Device and method to measure the DMD and other parameters of a multicore optical fiber

Optical fiber designs are depicted with a core having an alpha profile inner portion and a steep vertical step between the core and a cladding with no shoulder, referred to herein as a truncated core. A further aspect of this invention can include a trench between the truncated core and cladding. In this embodiment, the core performs as not only as the primary light guiding structure, but now also functions essentially the same as that of a trench structure. Thus, what was formally a trench can now be much less negative or even positive. Another embodiment of the present invention includes an optical fiber having a truncated core with the addition of a ledge or shoulder between the core and vertical step, followed directly by a cladding.

Optical fibers with truncated cores

Optical fiber refractive index profile designs having an alpha core profile and a negative index trench to control bend loss, are modified by truncating the edge of the alpha core profile and adding a ledge to the truncated core. The result is low bend loss and preservation of low differential mode delay and high bandwidth.

DMD performance in bend optimized multimode fiber

The specification describes multimode optical fibers with specific design parameters, i.e., controlled refractive index design ratios and dimensions, which render the optical fibers largely immune to moderately severe bends. The modal structure in the optical fibers is also largely unaffected by bending, thus leaving the optical fiber bandwidth essentially unimpaired. Bend performance results were established by DMD measurements of fibers wound on mandrels vs. measurements of fibers with no severe bends.

The specification describes a technique for drawing circular core multimode optical fiber using twist during draw to increase fiber bandwidth.

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Shrewsbury, MA, United States of America

Xinli Jiang