FEW MODE OPTICAL FIBER LINKS FOR SPACE DIVISION MULTIPLEXING

摘要

The invention relates to an optical link comprising N optical fibers, with N≧2. Each optical fiber comprises an optical core and an optical cladding surrounding the optical core, the optical core having a single αi graded-index profile with αi≧1, and the optical core having a radius R1i, where i E [1; N] is an index designating said optical fiber. Said optical cladding comprises a region of depressed refractive index ntrenchi, called a trench, surrounding the optical core. According to embodiments of the invention, for all optical fibers in said link, said optical core radius R1i and said length Li are chosen such that R1i≧13.5 μm and so as to satisfy a criterion C of quality. Thus, the invention provides a few-mode optical fiber link, which allow guiding an increased number of LP modes as compared to prior art FMF links, while reaching low Differential Mode Group Delay.

主权项

1. An optical link comprising N optical fibers, with N≧2, N being an integer,
each optical fiber comprising an optical core and an optical cladding surrounding the optical core, the optical core having a single αi graded-index profile with αi≧1, αi being a non-dimensional parameter defining an index profile shape of the optical core, and the optical core having a radius R1i and a maximal refractive index n0i, where iε[[1; N]] is an index designating said optical fiber, wherein the optical cladding having nCli, a refractive index nCli at an outer edge of the optical cladding, wherein said optical cladding comprises a region of depressed refractive index-ntrenchi, ntrench being a trench, surrounding the optical core, said trench having an inner radius R2i, with R2i≧R1i, and an outer radius R3i, with R3i>R2i, said optical link having an average optical core radius R1link satisfying a criterion C of quality of optical communications defined by the following equation:C=10·Max|DMGDlink|(R1link2·Dn1link)3 where DMGDlink is the Differential Mode Group Delay between two guided modes in said optical link, where Max|DMGDlink| is an absolute maximum value of Differential Mode Group Delay between any combination of guided modes in said optical link, whereR1link=∑i=1NR1iLi∑i=1NLiwith Li a length of optical fiber i in said link, and whereDn1link=∑i=1NDn1iLi∑i=1NLiwith Dn1=nCi−nCli is a core-cladding index difference for optical fiber i, at λ=λC, where λC is a central transmission wavelength of an operating band for the optical fiber,
and for at least one optical fiber i in said link, said optical core radius R1 is chosen such that R1i≧13.5 μm and for all optical fibers iε[[1; N]] in said link, said length Li are chosen such that C≦18.