Triangular-core large-mode-area photonic crystal fiber with low bending loss for high power applications

A triangular-core large-mode-area photonic crystal fiber structure has been designed with lower bending loss. The design works on the principle of bend induced mode filtering. Effects of the design parameters have been numerically investigated using the full vectorial finite-element method. In order to improve the effective mode area of fundamental mode along with the differential bending loss, five down-doped material rods have been introduced in place of five air holes in cladding. The structure supports effective mode-area of fundamental mode as large as 794  μm² with nominal bend loss of 0.064  dB/m at bend radius of 15 cm. This structure is able to suppress all unwanted nonlinear effects and can be a potential candidate for designing compact high power delivery devices.