Utilizing Joukowsky transformation in the design of optical fiber for elliptical-to-circular mode conversion.

This study addresses the challenge of enhancing coupling efficiency between optical fibers and elliptical Gaussian beams emitted by semiconductor lasers, particularly in fiber communication systems. We introduce a method for fiber design utilizing the Joukowsky transformation to facilitate efficient mode transformation from elliptical to circular, thereby augmenting the coupling efficiency with both single-mode and multimode fibers. Theoretical analysis and numerical simulations demonstrate that the fiber with a structurally transitional core maintains high-efficiency mode transformation across various lengths, and its structure has been optimized accordingly. Additionally, our investigation reveals the designed fiber's ability to preserve polarization states, which could have significant implications in precision optical applications. The proposed design offers an approach to improving performance in optical communication systems, especially in wavelength-division multiplexing (WDM) transmission systems and fiber lasers.