Design and Fabrication of Large-Mode Area Air-Clad Leakage Channel Fiber With Superior Bending Characteristics

We investigate the bending characteristics of leakage channel fibers (LCFs) to achieve large-mode area and effectively single-mode operation with a practically allowable bending radius of 5 cm for compact Yb-doped fiber laser applications. We design and fabricate a two-ring air-clad LCF whose bending characteristics have been studied both by numerical analysis through the full-vectorial finite element method and experimentally. The LCF has bend-loss of 0.09 dB/m and effective area of 350 μm
²
for a 5-cm bending radius. The single-mode nature of the bent LCF at 1064 nm is presented.