使用MCVD设备制取62.5μm大芯径、大数值孔径光纤预制棒的新工艺探索

总结了使用ＭＣＶＤ设备制备大芯径、大数值孔径光纤预制棒的新工艺。探索在不掺硼的情况下，在预制棒芯层逐层增加ＧｅＣｌ４的流量。在内包层掺氟以降低内包层折射率。解决了为达到较高折射率差Δｎ，在芯层掺锗过多而引起光纤预制棒在沉积后期和缩棒过程中由材料的热膨胀系数而导致的炸裂问题。并通过改变火焰平移速度，提高了沉积速率，缩短了制棒时间。所拉制的光纤、数值孔径ＮＡ高达０．３０。

Investigation of new technique for using MCVD equipment to preparing 62.5μm fiber preforms with large core and large NA

It has reported a new technique that using MCVD equipment prepares 62 5μm fiber preforms with large core and large NA. Under the condition of doping no Boron, the flow of GeCl 4 is increased step by step in the core of the preforms. In order to depress intercladding refractive index, the inter cladding is doped by fluorine (F). Because germanium is excessively doped in the core of preforms for high refractive index difference Δ n , the problem of splitting caused by the different thermal expansion coefficient of material has been solved in later period of deposition and collapse. By changing the moving velocity of the torch, the rate of deposition has been increased and the time for preparing the preforms has been reduced. The NA of the fibers to be drawn can be up to 0 30.