纯石英芯掺氟玻璃包层光纤的数值孔径

Numerical aperture of optical fiber with pure quartz core and fluorine-doped glass cladding

纯石英芯掺氟玻璃包层光纤是一种新结构的大芯径光纤,纤芯材料是纯石英玻璃,包层材料是掺氟石英玻璃,由于氟杂质可以降低石英玻璃的折射率,故纤芯材料与低折射率的包层材料可以组成传光波导。国外是采用POD(等离子体外相沉积)技术生产这种光纤,我们采用的是国内首创的管棒熔融套装法,制成了相同结构的光纤,为了提高光纤的性能,我们对该光纤进行了低、高折射率双层涂料涂覆,在测试中发现光纤的数值孔径参数随着光纤测试样品涂覆长度的变化而变化,变化范围为0.1889～0.3152。

Optical fiber with large pure quartz core and fluorine-doped glass cladding is a new structure of large core fiber,the material of core is pure quartz glass,and the cladding is quartz glass doped with fluorine,because the fluorine impurity can reduce the refractive index of the quartz glass, so the core and cladding material with low refractive index can consist of the light waveguide. It is made by POD（ plasma outside deposition） technic in abroad ,we use creatively the rode in tube method to make it with the same structure in domestic,in order to promote the property of the fiber, we coat it with double coating material, i. e. in-coating with low refractive index and out-coating with high refrac- tive index,we found that the numerical aperture of the fiber is influenced greatly, which changes from 0. 1889 to 0. 3152 with the coating length changes shorter and shorter.