Tutorial on all-fiber wavefront shaping

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Tutorial: How to build and control an all-fiber wavefront modulator using mechanical perturbations
Ronen Shekel, Kfir Sulimany, Shachar Resisi, Zohar Finkelstein, Ohad Lib, Sébastien M Popoff, and Yaron Bromberg
J. Phys. Photonics 6 0330022 (2024)
arXiv:2312.01352

Multimode optical fibers support the dense, low-loss transmission of many spatial modes, making them attractive for technologies such as communications and imaging. However, information propagating through multimode fibers is scrambled, due to modal dispersion and mode mixing. This is usually rectified using wavefront shaping techniques with devices such as spatial light modulators. Recently, we demonstrated an all-fiber system for controlling light propagation inside multimode fibers using mechanical perturbations, called the fiber piano. In this tutorial we explain the design considerations and experimental methods needed to build a fiber piano, and review applications where fiber pianos have been used.

The working concept of the fiber piano. Mechanical bends are applied along the multimode fiber. Different bends (depicted by red, blue, and green conformations of the fiber), yield different output patterns at the distal end of the fiber. To obtain a desired pattern, an optimization algorithm is employed to find the configuration of bends that optimizes a cost function of the output field.