Optical memory effect in square multimode fibers

We demonstrate experimentally the existence of a translational optical memory effect in square-core multimode fibers. We found that symmetry properties of square-core waveguides lead to speckle patterns shifting along four directions at the fiber output for any given shift direction at the input. A simple theoretical model based on a perfectly reflective square waveguide is introduced to predict and interpret this phenomenon. We report experimental results obtained with 532-nm coherent light propagating through a square-core step-index multimode fiber, demonstrating that this translational memory effect can be observed for shift distances up to typically 10 mu m after propagation through several centimeters of fiber. (C) 2021 Optical Society of America

Automated summary

Experimental demonstration of a translational optical memory effect in square-core multimode fibers, where symmetry properties of square-core waveguides lead to speckle patterns shifting along four directions. A simple theoretical model based on perfectly reflective square waveguides is used to predict and interpret this phenomenon. Experimental results show that this translational memory effect can be observed for shift distances up to typically 10 micrometers after propagation through several centimeters of fiber.