Bend-resistant stress-type segmented cladding large-mode-area single-mode fibers

We propose a novel bend-resistant stress-type large-mode-area fiber with segmented cladding, to the best of our knowledge, in which a high refractive index stress rod is introduced at the core, to improve the loss ratio between the least high-order mode (HOM) and fundamental mode loss, and to reduce the fundamental mode loss effectively. The mode loss and effective mode field area with or without heat load, and mode field evolution between the straight and bending transition are investigated, by utilizing the finite element method and the coupled-mode theory. The results show that the effective mode field area and the loss of the fundamental mode can reach up to 1050.1 µm2 and 0.0055dB⋅m-1, respectively, and the loss ratio between the least loss HOM and fundamental mode loss is greater than 210. The coupling efficient of the fundamental mode in the straight-bending transition reaches 0.85 at a wavelength of 1.064 µm and a bending radius of 24 cm. In addition, the fiber is insensitive to the bending direction and has excellent single-mode performance in any bending direction; the fiber maintains single-mode operation under heat load from 0 to 8 W/m. This fiber has potential application in compact fiber lasers and amplifiers.