Optimal design of large mode area all-solid-fiber using a gray relational optimization technique

Abstract

The multi-objective orthogonal optimization combined with gray relational analysis method is presented for designing large mode area all-solid-fiber with effective single-mode operation in the bent state. The bending performance of fiber was carried out taking the bending loss and effective mode area as objective functions, taking the width of inner-trench, width of resonant ring, refractive index of the inner- trench, the distance from the out-trench to the resonant ring, the width of out-trench and the refractive index of the out-trench as design variables. The results show the resonance ring added in the core can enhance the coupling between the high-order mode and the cladding mode and filter out the high-order mode to ensure the single-mode operation. The trench added to the cladding can increase the refractive index difference between the core and the cladding. The bending loss of the fundamental mode is limited and the anti-bending loss performance of the fiber is enhanced. After optimization, the bending loss is 0.00953 dB/m and the effective mode area can reach 776.45 µm2. Under the same bending radius, the bending loss of the designed optical fiber was reduced by an order of magnitude, the effective mode field area increased by 7.5%, and the Loss Ratio increased double. This kind of fiber shows great potential in compact fiber communication, high power fiber lasers and amplifiers.