Theoretical investigations of trench-assisted large mode-area, low bend loss and single-mode microstructured core fibers

We propose two different types of bend-insensitive microstructured core fiber (MCF) designs—trench-assisted MCF (TAMCF) and hole-assisted MCF (HAMCF) operating over C-band to achieve large mode-area, low bending loss and single-mode operation. We numerically demonstrate the design principles and constraints on bend-limited large-mode-area microstructured core optical fibers and investigate their modal properties by using fully-vectorial effective index method and finite element method. The TAMCF shows larger effective mode-area >1000 μm2 at 1550 nm with a bending loss <0.1 dB/m, whereas the HAMCF exhibit very low bending loss value −10−5 dB/m at the cost of reduced effective mode-area when the fibers are bent into 7.5 cm bending radius. However, calculations on differential leakage losses between two designs indicate TAMCF performs better. We have also investigated the effect of bending plane on the bend loss characteristics of proposed fiber designs.