Abstract We present a new type of few-mode fiber which features an elliptical ring-core with two stress rods. This type of few-mode fiber can separate the adjacent modes from each other. By using the high refractive index difference of 0.03 between the core and cladding and the birefringence caused by stress rods and elliptical ring core, 10 modes can be obtained. And the minimal effective refractive index difference between adjacent modes can be measured as 2.83 × 10−4. The performance of its anti-bending test shows that this special structure can achieve low loss characteristic and maintaining its mode intensity profile under the bending radius of 1.5 cm. And the effective refractive index differences (Δneff) are greater than 2 × 10−4 with the bending radius of 1 cm. It was measured to have good fault-tolerant ability under the condition of unsatisfactory structure. Finally, the simulation shows that the minimal Δneff of this type few-mode fiber in the whole C + L band is greater than 1.91 × 10−4. This special fiber is targeted at applications in spatial division multiplexing of optical channels, without the need for multiple-input multiple-output (MIMO) signal processing.

中文翻译：

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熊猫型椭圆环芯少模光纤

摘要 我们提出了一种新型的少模光纤，其特点是椭圆环纤芯和两个应力棒。这种类型的少模光纤可以将相邻的模式彼此分开。利用纤芯和包层之间0.03的高折射率差以及应力棒和椭圆环纤芯引起的双折射，可以获得10种模式。并且相邻模式之间的最小有效折射率差可以测量为2.83 × 10-4。其抗弯曲测试的性能表明，这种特殊结构在弯曲半径为1.5cm的情况下可以实现低损耗特性并保持其模式强度分布。并且有效折射率差（Δneff）大于2×10-4，弯曲半径为1 cm。测得它在结构不理想的情况下具有良好的容错能力。最后，仿真表明该类少模光纤在整个C+L波段的最小Δneff大于1.91×10−4。这种特殊光纤针对光信道空分复用应用，无需多输入多输出 (MIMO) 信号处理。