宽带放大器用碲基掺铒光纤结构参量的设计考虑

利用光波导理论及均匀展宽四能级模型，研究了宽带放大器用阶跃型折射率分布碲基掺铒光纤的结构参量—纤芯半径和相对折射率差的设计考虑.理论研究表明，在单模传输条件下，为获取最大信号增益，宜选择相对折射率差大的碲基掺铒光纤来构建光纤放大器.相对折射率差一定的情况下，在高泵浦功率、小信号输入或光纤长度短于各信道最佳增益长度时，选择纤芯半径大的碲基掺铒光纤可以得到大的信号增益；反之，宜选择纤芯半径小的碲基掺铒光纤.

A Consideration to Structure Parameter Design for Tellurite-based Erbium-doped Fiber applied in Broad-band Amplifiers

Based on the fiber waveguiding theory and hormgeneously broadened four energy-level model,the designing considerations of the fiber structure parameters-fiber core radius and relative index difference of tellurite-based erbium-doped fiber with step-type index distribution,which is applied in broad-band amplifiers,are presented theoretically.It is shown that the tellurite-based erbium-doped fiber with bigger relative index difference is needed to form fiber amplifier in order to get larger signal gain under single-mode conditions.While,for the same relative index difference,the bigger the fiber core radius,the larger the signal gain when in the state of high pump power,low signal input or shorter than the best fiber length.On the contrary,the smaller fiber core radius is needed.The above results will provide theoretical significance for the fabrication of new type broad-band tellurite-based erbium-doped fiber.