Abstract:
Methods for forming optical fiber preforms with low-index trenches are disclosed. According to one embodiment, the method includes depositing silica-based glass soot on a bait rod to form a low-index trench region of the optical fiber preform. The silica-based glass soot is deposited such that the low-index trench region has a first density. Thereafter a barrier layer having a second density greater than the first density is formed around the low-index trench region. Therafter, an overclad region is deposited around the barrier layer. The bait rod is then removed from a central channel of the trench-overclad assembly. A separate core assembly is inserted into the central channel. A down-dopant gas is then directed through the central channel of the trench-overclad assembly as the trench-overclad assembly is heated to dope the low-index trench region. The barrier layer prevents diffusion of the down-dopant from the low-index trench region into the overclad region.
Abstract:
According to one example of the invention an optical fiber comprises: (i) silica based, rare earth doped core having a first index of refraction n1; (ii) at least one silica based cladding surrounding the core and having a second index of refraction n2, such that n1> n2 with the following features, alone or in combination: said cladding includes 0.5 to 5 wt% F and 0.5 to 20 wt% B, said optical fiber has less than 8dB/km core background loss at a wavelength of 1280 nm. at least one of the core or cladding is doped with AI203 concentration is less than 2:1.
Abstract:
According to one example of the invention an optical fiber comprises: (i) silica based, rare earth doped core having a first index of refraction n1; (ii) at least one silica based cladding surrounding the core and having a second index of refraction n2, such that n 1 > n 2 ; wherein at least one of the core or cladding is doped with Al 2 O 3 , such that the ratio of max wt% to min wt% of Al 2 O 3 concentration is less than 2:1
Abstract translation:根据本发明的一个示例,光纤包括:(i)具有第一折射率n1的二氧化硅基稀土掺杂的核; (ii)至少一个围绕所述芯并且具有第二折射率n2的基于二氧化硅的包层,使得n1> n2; 其中所述芯或包层中的至少一个掺杂有Al 2 O 3,使得Al 2 O 3浓度的最大重量%与最小重量%的比率小于2:1