Study On Bend-Insensitive Fiber

With the development of FTTH, bend-insensitive fiber(BIF) has attracted more and more attention. This paper focuses on bending losses of the trench-assisted bend-insensitive optical fiber. This paper focuses on two kinds of bend-insensitive fiber with different structure of trench-assisted. One is flat trench-assisted structure. Another is gradually changing. For the trench-assisted bend-insensitive fiber, the refractive index difference of trench, the width of trench, the distance between the core and trench, fiber radius and refractive index of the coating layer are five important parameters which could influence the bending loss. Combining the five parameters, this paper investigated the impact of them on the two kinds of bend-insensitive fiber with different structure of trench-assisted. It is shown that:in the bend-insensitive fiber with flat trench-assisted structure, bending losses can be effectively reduced by changing the radius of the fiber. With refractive index of the coating layer increasing, the bending losses of the fiber could be effectively reduced for certain bending radius; In the bend-insensitive fiber with gradually changing trench-assisted structure, when the bending loss varies with the width of trench, there is a minimum bending loss point. The impact of fiber radius on the bending loss is very small. With refractive index of the coating layer increasing, the bending losses of the fiber could be effectively reduced for most bending radius; The conclusion is of significance for designing and manufacturing of bend-insensitive fibers.