Bend-Resistant Large Mode Area Fiber With an Azimuthally Segmented Trench in the Cladding

A bend-resistant large mode area fiber with an azimuthally segmented trench in the cladding is proposed and investigated in this paper. The loss ratio of the proposed fiber between the lowest higher order modes (HOMs) and fundamental mode can reach 1000, which is much larger than 130 of multi-trench fiber (MTF). Meanwhile, the mode area of the proposed fiber achieves 790 μm² at core radius of 23 μm, which is the same large as MTF. Moreover, the effective mode area of our design can achieve 920 μm² at core radius of 26 μm with effective single-mode operation at the bending radius of 20 cm. The fiber performance is stable with bending orientation at the range of [0°, 360°]. The proposed fiber ensures better HOMs suppression than the MTF. The new fiber design shows great potential in high-power fiber lasers.