In spatial division multiplexing (SDM)-based communication systems, each spatial mode can act as an independent information-bearing carrier capable of scaling the total transmission capacity by several orders of magnitude. It has been reported that in SDM networks the signal amplitude depends upon the optical-path-length (OPL) difference between the various optical modes. In this work, we realize SDM technique using a multimode fiber (MMF), because MMFs have a potential to increase transmission capacity drastically by transmitting signals over large number of modes separately. The system performance is analyzed on the basis of following parameters: visualizer spatial profile, mode index profiles, fiber transfer function, refractive index profile, bit error rate, and quality factor. Also we measure changes in the optical path length due to a phase-shifting laser beam. We conclude that MMFs have huge scope for future ultrahigh-capacity transmission systems employing SDM.

在基于空分复用（SDM）的通信系统中，每个空间模式都可以充当独立的承载信息的载体，能够将总传输容量缩放几个数量级。据报道，在SDM网络中，信号幅度取决于各种光学模式之间的光路长度（OPL）差异。在这项工作中，我们实现了使用多模光纤（MMF）的SDM技术，因为MMF有潜力通过分别通过大量模式传输信号来极大地提高传输容量。系统性能是基于以下参数进行分析的：可视化器空间轮廓，模式索引轮廓，光纤传递函数，折射率轮廓，误码率和品质因数。我们还测量了由于相移激光束导致的光程长度变化。我们得出的结论是，MMF对于采用SDM的未来超大容量传输系统具有广阔的范围。