Singh Sakshi, Labouesse Simon, Piestun Rafael
Department of Electrical, Computer, and Energy Engineering, University of Colorado Boulder, Colorado 80309, USA.
J Lightwave Technol. 2021 May 1;39(9):2961-2970. doi: 10.1109/jlt.2021.3057615. Epub 2021 Feb 8.
Multimode fibers are attractive for imaging, communication, computation, and energy delivery. Unfortunately, intermodal and polarization coupling precludes direct control of the delivered mode composition. We present a technique to tailor the mode composition at the output of a multimode fiber with thousands of modes, which we refer to as myriad-mode fiber, using its experimentally measured transmission matrix. While precise mode control has been demonstrated in typical multimode fibers with up to 210 modes, the method proposed here is particularly useful for high mode number fibers, such as when the number of modes is comparable to the number of modes of the wavefront shaping spatial light modulator. To illustrate the technique, we select different subsets of modes to create focal spots at the output of a fiber with 7140 modes. Importantly, we define efficiency and fidelity metrics to evaluate the mode control and demonstrate the relationship between efficiency, fidelity, and the spatial location of the spots across the distal fiber cross-section.
多模光纤在成像、通信、计算和能量传输方面具有吸引力。不幸的是，模间耦合和偏振耦合妨碍了对传输模式组成的直接控制。我们提出了一种技术，利用实验测量的传输矩阵来调整具有数千种模式的多模光纤（我们称之为万模光纤）输出端的模式组成。虽然在具有多达210种模式的典型多模光纤中已经证明了精确的模式控制，但这里提出的方法对于高模式数光纤特别有用，例如当模式数量与波前整形空间光调制器的模式数量相当时。为了说明该技术，我们选择不同的模式子集，在具有7140种模式的光纤输出端创建焦点。重要的是，我们定义了效率和保真度指标来评估模式控制，并展示了效率、保真度与远端光纤横截面上光斑空间位置之间的关系。
