Novel bend-resistant large-mode-area photonic crystal fiber with a triangular-core

Abstract

A novel bend-resistant large-mode-area photonic crystal fiber with a triangular-core is proposed in this paper. In this structure, the circle air holes with uniform size are used to reduce the difficulty in fabrication. At a wavelength of 1.064 μm, mode field area of the fundamental mode is 1386 μm2 in a straight state, and it is 1153 μm2 at a bending radius of 30 cm. The decrement of mode field area in a bent state is only 16.85% compared with that in a straight state. When a bending radius is 30 cm, bending loss of the fundamental mode is 0.087 dB/m while bending loss of the second order mode is higher than 1.5 dB/m. The bending loss difference between fundamental mode and second order mode is large enough to ensure that the fiber conforms to the single mode operation conditions. Furthermore, when the fiber is bent with a bending radius of 30 cm, the bending orientation angle can be extended to ±180°, breaking the limit of the bending orientation. The fiber with large mode area, small decrement in mode field area, low bending loss and low sensitivity of bending orientation makes a great contribution to the miniaturization of high power fiber laser and fiber amplifier.