Mode division multiplexing (MDM) has attracted great attention in recent years to increase the network capacity. To apply MDM in data center applications, a low-cost and low power consumption system is desired. In this letter, we utilize 850-nm single-mode VCSEL as the laser source and report mode division multiplexed transmission over a standard single-mode fiber, which is two-mode at 850 nm. Due to the small spot size and low numerical aperture, single-mode VCSEL can be coupled into single-mode fibers with low loss. The mode multiplexer and de-multiplexer devices are designed and fabricated based on fiber mode selective couplers using Hi780 fiber as the 850-nm single-mode launch and receiving fiber and standard single-mode fiber as the few-mode transmission fiber. The MDM system supports two channels, corresponding to the LP ₀₁ and LP ₁₁ mode in the few-mode transmission fiber. Detailed characterizations of the multiplexer and de-multiplexer are conducted including the insertion loss and crosstalk measurements. System transmission at 25 Gb/s shows error free performance over 1-km standard single- mode fiber for both channels. The utilization of VCSEL and standard single-mode fiber can potentially provide a low-cost solution for MDM systems in data center applications.

中文翻译：

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使用标准单模光纤的模分复用 850-nm 单模 VCSEL 传输

近年来，模分复用（MDM）在增加网络容量方面引起了极大的关注。为了将 MDM 应用到数据中心应用中，需要一种低成本、低功耗的系统。在这封信中，我们使用 850 nm 单模 VCSEL 作为激光源，并报告了标准单模光纤上的模分复用传输，该光纤是 850 nm 的双模光纤。由于光斑尺寸小、数值孔径小，单模VCSEL可以耦合到低损耗的单模光纤中。采用Hi780光纤作为850nm单模发射和接收光纤，标准单模光纤作为少模传输光纤，基于光纤模式选择耦合器设计和制作了模式复用器和解复用器装置。MDM系统支持两个通道，对应LP ₀₁和 LP ₁₁模式在少模传输光纤中。进行了多路复用器和多路分解器的详细表征，包括插入损耗和串扰测量。25 Gb/s 的系统传输在两个通道的 1 公里标准单模光纤上显示出无差错性能。VCSEL 和标准单模光纤的使用可能为数据中心应用中的 MDM 系统提供低成本解决方案。