This letter proposes a high data rate optical transmission system for data center interconnects (DCIs), where we employ vertical cavity surface emitting lasers (VCSEL) and graded index few-mode fibre (GI-FMF) having modal bandwidth of around 24.3 GHz.km to enhance the link capacity and range. Additionally, we consider PAM-4 modulated data transmission at the rate of 2×100 Gbps using a pair of VCSELs and employing mode group division multiplexing (MGDM) of two linearly polarized (LP) modes LP01 and LP11 of the GI-FMF. Digital signal processing (DSP) techniques are applied at the receiver to process the received PAM-4 signals for equalization in order to mitigate the channel impairments. Furthermore, standard OM3 and OM4 fibers are considered as a benchmark to compare the transmission performance of the designed GI-FMF. We observe that the designed GI-FMF supports longer transmission distance for both LP01 and LP11 modes upto 900 m and 450 m at 50 Gbps and 100 Gbps data rates, respectively, while achieving lower receiver sensitivities for forward error correction (FEC) limit of 3.8 × 10−3. The proposed optical transmission system can be a potential applicant in future data center networks supporting transmission rates in 800 Gbps to 1.6 Tbps range.

中文翻译：

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线偏振模式通过用于数据中心互连的少模光纤启用 PAM-4 数据传输

这封信提出了一种用于数据中心互连 (DCI) 的高数据速率光传输系统，其中我们采用了垂直腔面发射激光器 (VCSEL) 和模态带宽约为 24.3 GHz.km 的渐变折射率少模光纤 (GI-FMF)以提高链路容量和范围。此外，我们考虑使用一对 VCSEL 并采用 GI-FMF 的两个线性偏振 (LP) 模式 LP01 和 LP11 的模式组分复用 (MGDM) 以 2×100 Gbps 的速率进行 PAM-4 调制数据传输。在接收器处应用数字信号处理 (DSP) 技术来处理接收到的 PAM-4 信号以进行均衡，从而减轻信道损伤。此外，标准 OM3 和 OM4 光纤被认为是比较设计的 GI-FMF 传输性能的基准。我们观察到，设计的 GI-FMF 支持 LP01 和 LP11 模式在 50 Gbps 和 100 Gbps 数据速率下分别达到 900 m 和 450 m 的更长传输距离，同时实现了较低的接收器灵敏度，用于前向纠错 (FEC) 限制为 3.8 × 10−3。拟议的光传输系统可以成为未来数据中心网络中支持 800 Gbps 至 1.6 Tbps 范围传输速率的潜在应用。