We present a numerical analysis of noise performance improvement of the erbium-doped fiber amplifier by flatting the mode field intensity distribution within the interaction region of erbium ions. Three different refractive index types of erbium-doped fiber were used to study the effect of the pump mode intensity distribution on noise performance. The results show that taking advantage of the depressed refractive index erbium-doped fiber which has a flat mode distribution in the fiber core, the maximum reduction of nearly 0.53 dB for noise figure was achieved across the full C-band. Based on the center depressed refractive index profile, the noise figure was further decreased by about 0.1 dB by reducing the doping radius to 0.71 μm. Finally, maintaining the same gain level of ∼38.3 dB, a NF reduction of ∼0.63 dB was realized by introducing the center depressed refractive index profile and narrowing the erbium doping region. It is suggested that our investigation shows great potential for improving the noise performance of the erbium-doped fiber amplifier.

中文翻译：

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通过调整掺铒光纤的模场分布实现光纤放大器中的超低噪声系数


我们通过使铒离子相互作用区域内的模场强度分布平坦，对掺铒光纤放大器的噪声性能改进进行了数值分析。使用三种不同折射率类型的掺铒光纤来研究泵浦模式强度分布对噪声性能的影响。结果表明，利用纤芯中具有平坦模式分布的降低折射率掺铒光纤，在整个C波段实现了噪声系数最大降低近0.53 dB。基于中心下压折射率分布，通过将掺杂半径减小至 0.71 μm，噪声系数进一步降低了约 0.1 dB。最后，在保持~38.3 dB的相同增益水平的情况下，通过引入中心下压折射率分布和缩小铒掺杂区域，实现了NF降低~0.63 dB。这表明我们的研究显示出改善掺铒光纤放大器噪声性能的巨大潜力。