Efficient Suppression of Backward Light Scattering for Optical Fiber Cladding Light Stripper

This study investigates a method for the effective suppression of backscattering within optical fiber cladding light strippers (CLSs) with a periodically grooved structure. First, the relationship between the backscattering of cladding light and the surface roughness of the cladding for a periodically grooved CLS is theoretically investigated using the ray-tracing method. It is found that the backscattering of cladding light depends on the surface roughness of the grooves and that undesired backscattering significantly affects the stripping capability of a CLS. Based on the theoretical results, we propose a periodically grooved CLS structure with multiple unetched sections of a suitable length and verify its effectiveness by comparing its lightwave stripping performance with that of a conventional CLS design in both theoretical and experimental ways. Unlike the conventional structure, our proposed structure demonstrates almost uniform lightwave stripping without localized overheating.