Direct image transmission through a multi-mode square optical fiber

Abstract

We explore the potential for direct image transmission through a square optical fiber. We show that when an image is sampled appropriately and its optical Fourier transform imaged on the end of a square fiber with perfectly reflecting walls, the components in the Fourier transform excite corresponding fiber modes. Specifically, even–even fiber modes carry information from one pixel only, while the odd modes carry information from neighboring pixels and give rise to cross-talk. When the odd modes are suppressed, the image can be perfectly recovered at the end of the fiber by a second optical Fourier transform. We suggest a method of suppressing the odd modes. In our system, dispersion of the mode phase velocity gives rise to different arrival times for the information in different image pixels, but has little or no effect on the output intensity distribution. We show that the square shape of the fiber is critical in forming the output image and confirm our theoretical predictions by computer simulation.