包层模耦合抑制的B/Ge共掺光敏光纤

B/Ge Co-Doped Photosensitive Fiber with Suppression of Cladding Mode Coupling

光纤光栅的包层模耦合造成的布拉格波长短波长带损耗限制了光栅的使用范围。分析了同时具有下陷内包层和光敏内包层的光敏光纤可以在相当程度上抑制包层模耦合 ,并采用化学汽相淀积工艺制作了硼和锗共掺(B Ge)的光纤 ,在其下陷内包层内也掺入了适量的硼和锗 ,具有一定的光敏性 ,经用相位掩膜法写入紫外光纤光栅证实该光敏光纤不但具有较大的光敏性 ,而且确实抑制了包层模耦合。

Cladding mode coupling will lead loss on the short wavelength side of Bragg wavelength and thus limits the grating's wide use. A novel photosensitive fiber design is proposed that have both the depressed cladding and the photosensitive inner cladding in the same fiber. It can suppress cladding mode coupling in some extent. B/Ge co-doped fiber grating with depressed cladding which was also doped with boron and germanium was fabricated. The transmission spectrum of written grating in it verified its larger photosensitivity and suppression of cladding mode coupling.