Analysis of Spectral Bendloss Filtering in a Cladding-Pumped W-Type Fiber Raman Amplifier
Analysis of Spectral Bendloss Filtering in a Cladding-Pumped W-Type Fiber Raman Amplifier
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DOI：
10.1109/jlt.2010.2052786
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发表时间：
2010-08
影响因子：
4.7
通讯作者：
J. Ji;C. Codemard;J. Nilsson
中科院分区：
文献类型：
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作者：
J. Ji;C. Codemard;J. Nilsson
我们设计了一种W型芯双包层光纤，用于工作在一阶斯托克斯波长的包层泵浦光纤拉曼放大器。与传统的阶跃折射率芯相比，W型芯允许更大的内包层，从而可以利用光束质量相对较差的泵浦源。这是因为寄生拉曼转换到二次斯托克斯可以被弯曲损耗抑制，而W型光纤的尖锐的光谱特性允许在一次斯托克斯保持较低的损耗。在没有弯曲损耗滤波的情况下，内包层面积与斯托克斯波的有效面积之比被限制在大约8。采用弯曲损耗过滤的W型光纤，芯径可达18μm左右，内包层直径可达82μm左右，面积比可达34。我们还讨论了光损伤和脉冲区泵浦信号走离对亮度增强的限制。
We design a double-clad fiber with a W-type core for use in a cladding-pumped fiber Raman amplifier operating at the 1st-Stokes wavelength. Compared to a conventional step-index core, a W-type core allows for a larger inner cladding so that pump sources with relatively poor beam quality can be utilized. This is because parasitic Raman conversion to the 2nd Stokes can be suppressed by bending loss, while the sharp spectral characteristics of a W-type fiber allows the loss to be kept low at the 1st Stokes. Without bendloss filtering, the ratio between the inner-cladding area and the effective area of the Stokes wave is limited to approximately eight. With a bendloss-filtered W-type fiber, area ratios of 34 are possible for core diameters up to around 18 μm and inner-cladding diameters up to around 82 μm. We also discuss limitations on the brightness enhancement due to optical damage and pump-signal walk-off in the pulsed regime.