A bend-resistant low bending loss and large mode area two-layer core single-mode fiber with gradient refractive index ring and multi-trench

We propose a bend-resistant large mode area single-mode fiber with low bending loss. The fiber consists of three parts, including a two-layer core, a gradient refractive index ring and multi-trench. Performance of the proposed fiber is investigated by using a finite element method at 1550 nm wavelength. Large mode area of 2622 mu m(2) at a bend radius of 20 cm can be achieved with the function of the two-layer core and the gradient refractive index ring. The gradient refractive index ring acts as a resonant ring, which also contributes to bend-resistant performance. Bending loss can be reduced to about 0.092 dB/m due to the multi-trench in the cladding, which is also beneficial to improve transmission efficiency. Moreover, the fiber can ensure single-mode operation by exploiting high suppression of the higher order modes. The bending direction has no effect on the performance of the fiber because of the symmetric design.