Mode coupling in large-diameter multi-mode silica optical fibers

Abstract

We report an experimental study on mode coupling in various large-diameter multi-mode silica optical fibers. The evolution of the far-field angular power distribution is experimentally measured, and the mode coupling characteristics are studied on a variety of fibers with diverse parameters, including core/cladding diameter (50-400µm/125-480µm), length (few to hundreds of meters), NA (0.15-0.46), etc. The influences of fiber geometry, bending are discussed. This study could provide practical guidance in designing power delivery fibers for high-power diode, solid-state and fiber lasers to preserve the input brightness and beam quality.