We experimentally demonstrate mode-division multiplexed (MDM) transmission using eight orbital angular momentum (OAM) modes over a single span of 100-km low-attenuation and low-crosstalk ring-core fiber (RCF). Each OAM mode channel carries 10 wavelength-division multiplexing (WDM) signal channels in the C band, with each WDM channel in turn transmitting 16-GBaud quadrature phase-shift keying signal. An aggregate capacity of 2.56 Tbit/s and an overall spectral efficiency of 10.24 bit/(s · Hz) are realized. The capacity-distance product of 256 (Tbit/s) · km is the largest reported so far for OAM fiber communications systems to the best of our knowledge. Exploiting the low crosstalk between the OAM mode groups in the RCF, the scheme only requires the use of modular 4×4 multiple-input multiple-output processing, and it can therefore be scaled up in the number of MDM channels without increasing the complexity of signal processing.

中文翻译：

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WDM 信号在 100 公里单跨 OAM 光纤上的模分复用传输

我们在 100 公里低衰减和低串扰环芯光纤 (RCF) 的单个跨距上使用八个轨道角动量 (OAM) 模式通过实验证明了模分复用 (MDM) 传输。每个 OAM 模式通道在 C 波段承载 10 个波分复用 (WDM) 信号通道，每个 WDM 通道依次传输 16-GBaud 正交相移键控信号。实现了 2.56 Tbit/s 的总容量和 10.24 bit/(s·Hz) 的总频谱效率。据我们所知，256 (Tbit/s)·km 的容量-距离乘积是迄今为止报告的最大的 OAM 光纤通信系统。利用RCF中OAM模式组之间的低串扰，该方案只需要使用模块化4×4多输入多输出处理，