Design and analysis of multi-ring microstructured-core optical fibers

A novel design of single-mode large-mode-area optical fiber is presented. The core is composed of alternate high and low-index regions to form an effectively low-index contrast between the core and the cladding. The proposed fiber is investigated by the finite-element method with anisotropic perfect matched layer boundary conditions. In addition, the bending losses of the fibers are calculated and compared with those of the step-index optical fibers. In particular, numerical simulations demonstrate that single-mode operation can be achieved in one such fiber with mode area larger than 600 μm² at the wavelength of 1.55 μm and bending loss lower than 0.02 dB/m for bending radius greater than 20 cm.