Image transmission and radiation by truncated linearly polarized multimode fiber

We study the use of individual multimode fibers for the purposes of microendoscopy. We discuss the question of image decomposition in the several modes propagating over the fiber and their scattering at the truncated fiber end. We derive analytically the scattering matrix of the "fiber-to-air" interface, we quantify the extent of intermodal coupling, and we evaluate the radiation diagram from the fiber end. Results show that intermodal coupling is weak, so that it appears possible to "capture" an external image and transmit the same through the fiber, after appropriate phase correction, without excessive distortion.