In this article, we experimentally propose an efficient wide flat gain bandwidth with a parallel hybrid fiber amplifier. The setup includes parallel amplifier branches. In the first branch, serial erbium-doped and Raman fiber amplifiers are used. In the second branch, only a Raman fiber amplifier is used. Three Raman pump power units (i.e., 1410, 1480, and 1495 nm) are used to achieve Raman gain at different optical communication bands. At optimum pump powers and at a small-signal power of −30 dBm, an average gain of 18.5 dB with a maximum gain variation of 3 dB and a gain flatness bandwidth of 83 nm, that is, from 1527 to 1610 nm, is achieved. This gain flatness is expanded to 92 nm (1525–1617 nm) at a large input signal power of −5 dBm with an average gain level of 13 dB. In our proposed amplifier, the Raman amplification peaks (1510 and 1595 nm) are chosen to be far from the erbium amplification peak (1530–1570 nm) in order to avoid the overlapping and the saturation in the first amplifier branch. Therefore, due to such wavelength optimization in addition to the recycling the residual Raman pump power, a wide flatness gain bandwidth is achieved for both of low and large input signal powers.

中文翻译：

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具有并行混合光纤放大器的高效宽平坦度增益带宽

在本文中，我们通过实验提出了一种具有并行混合光纤放大器的高效宽平坦增益带宽。该设置包括并行放大器分支。在第一个分支中，使用串行掺铒光纤放大器和拉曼光纤放大器。在第二个分支中，仅使用拉曼光纤放大器。三个拉曼泵浦功率单元（即 1410、1480 和 1495 nm）用于在不同的光通信波段实现拉曼增益。在最佳泵浦功率和−30 dBm 小信号功率下，平均增益为 18.5 dB，最大增益变化为 3 dB，增益平坦度带宽为 83 nm，即从 1527 到 1610 nm . 该增益平坦度在 -5 dBm 的大输入信号功率下扩展到 92 nm (1525–1617 nm)，平均增益电平为 13 dB。在我们提出的放大器中，选择拉曼放大峰（1510 和 1595 nm）远离铒放大峰（1530-1570 nm）以避免第一放大器分支中的重叠和饱和。因此，由于这种波长优化以及回收剩余的拉曼泵浦功率，对于低输入信号功率和大输入信号功率都实现了宽平坦增益带宽。