掺铒玻璃波导放大器中抽运光信号光重叠因子分析

通过分析掺铒(Er3 )玻璃波导放大器(EDWA)的放大增益机理,提出抽运光与信号光光模场分布之间的归一化重叠积分因子(Γ),并引入到掺铒波导放大器增益模拟计算中,使理论模型更切合实际。以Ag -Na 二次离子交换工艺制作的具有埋入型渐变折射率分布的掺铒波导放大器为例,采用数值方法模拟了条形波导截面上的二维折射率分布及抽运光、信号光的光模场分布。计算了不同工艺参量设置下的Γ大小,讨论Γ对放大器增益的影响。结果显示,在二次离子交换制作过程中设置适当工艺参量优化折射率分布,能有效改善波导中抽运光与信号光光模场分布之间的重叠因子,提高掺铒波导放大器的增益。计算结果显示,在一定条件下,Γ从0.5增至0.8,每厘米长度掺铒波导放大器的放大增益可提高近1.5 dB。

Analysis of Overlap Factor between Pump-and Signal-Light Intensity profiles in Er-Doped Waveguide Amplifier

The normalized overlap factor between pump- and signal-light intensity profiles in the waveguide (Γ) is introduced, and be taken into account in the theoretic model of the Er-doped glass waveguide amplifier (EDWA). For an EDWA with buried graded refractive-index profile which is fabricated by Ag+-Na+ two-step ion-exchange on process Er-doped phosphate glass, the two dimensional refractive-index profiles, and the guide modes of both pump and signal light in the channel waveguide is obtained using the numerical methods. The normalized value of Γ with different fabrication parameters is calculated, and its effect on the gain of EDWA has been investigated. The results show that by tailoring the fabrication parameters, the overlap factor between pump and signal light in the waveguide can be optimized and the gain of EDWA can be enhanced. With Γ enhanced from 0.5 to 0.8, the gain of EDWA can be improved nearly 6 dB.