Single‐mode optical fibers with zero total dispersion at wavelength 1.3 and 1.55 μm. fiber with α‐power index core and triple clad

Abstract

AbstractSingle‐mode optical fibers with an α‐power index core (α = 1, 2, 6, ∞) and a triple clad have been designed under the following two conditions: (I) the total dispersion at wavelengths of 1.3 and 1.55 μm is zero; and (II) the cut‐off wavelength λc for the second mode is less than 1.15 μm. In this paper, the sensitivity of the total dispersion, the equivalent bending radius (the radius at which the bending loss is 0.01 dB/km), and the splice loss of those fibers are discussed. The clad has an ideal triple layer structure (the relative index difference between the first and outer cladding is Δ2 and that between the second and outer cladding is Δ3). For a given value of α which determines the core refractive index profile, Δ1. (the relative index difference between the core and outer cladding), and a (core radius) can be chosen freely. In this paper, for a given α the fiber, satisfying conditions (I) and (II), was designed under the conditions that (1) Δ1 = const, and (2) \documentclass{article}\pagestyle{empty}\begin{document}$ A\mathop \Delta \limits_ = \int\limits_0^{a/w} {n(r/w,\;\lambda)dr\; = - const(w\mathop \Delta \limits_ = a + t_1 + t_2, t_m;} $\end{document} m‐th cladding layer width, m = 1, 2). Comparing the fiber with a core of α = 1, 2 and 6 (t2/t1 = 1.0, Δ2 < 0, Δ3 < 0), the step index core fiber (α = ∞). has the following characteristics whether the fiber is designed under condition (1) or (2): 1) a lower sensitivity for the core radius and wavelength; 2) a smaller equivalent bending radius; 3) a smaller splice loss in the case where d/a = const (d: axial displacement). For the case where α = ∞, the structure with Δ2 > 0 and Δ3 < 0 was investigated and compared with the structure with Δ2 < 0 and Δ3 > 0.