초록 ▼

A method for making an optical fiber fusion joint between two dissimilar single mode optical fibers (10,40) where the fibers have different core sizes and/or different refractive index profiles due to different patterns of dopant. One fiber may be a standard step-index communication fiber with a 9 .

A method for making an optical fiber fusion joint between two dissimilar single mode optical fibers (10,40) where the fibers have different core sizes and/or different refractive index profiles due to different patterns of dopant. One fiber may be a standard step-index communication fiber with a 9 .mu.m core diameter and a numerical aperture (NA) of about 0.1, and the second fiber may be a dispersion compensating fiber (DCF) with a multiple layer refractive index profile. The second fiber alternatively may have a smaller core and a higher NA, up to about 0.3. A diffused dopant region, with a gradual longitudinal variation in diffusion, is included adjacent to the splice. The diameter of the communications fiber core increases gradually within the diffusion region as the splice joint is approached along this fiber. The diffusion of the various dopants in the second fiber tend to cause its refractive index profile to converge optically to that of the diffused step index communication fiber. As a consequence of the gradually varying diffusion region, the optical losses associated with the splice are relatively low, even when there is relatively high mismatch between the mode field diameters and mode field shapes (at a signal wavelength) in the respective fibers. In another embodiment a fiber fattening technique is used to fatten the fibers in the region of the splice to reduce losses.

대표청구항 ▼

1. An annealed optical fiber joint comprising first and second doped optical fibers fusion spliced to one another for operation in a predetermined wavelength range, the second fiber having a different core size and different refractive index profile from the first fiber, and a longitudinal diffused

1. An annealed optical fiber joint comprising first and second doped optical fibers fusion spliced to one another for operation in a predetermined wavelength range, the second fiber having a different core size and different refractive index profile from the first fiber, and a longitudinal diffused region associated with the fusion splice, the longitudinal diffused region comprising a length of both of the fibers wherein the amount of diffusion increases as the splice is approached along each fiber, the length of the diffused region in each fiber being 3 mm or more; and the fusion splice having a total splice loss, over the range of signal wavelengths, of less than 0.2 dB.