Single-mode chirally-coupled-core fibers with larger than 50µm diameter cores

Abstract

In this paper, we report an advance in increasing core size of effective single-mode chirally-coupled-core (CCC) Ge-doped and Yb-doped double-clad fibers into 55µm to 60µm range, and experimentally demonstrate their robust single-mode performance. Theoretical and numerical description of CCC fibers structures with multiple side cores and polygon-shaped central core is consistent with experimental results. Detailed experimental characterization of 55µm-core CCC fibers based on spatially and spectrally resolved broadband measurements (S2 technique) shows that modal performance of these large core fibers well exceeds that of standard 20μm core step-index large mode area fibers.