This paper presents a comprehensive comparison of the propagation characteristics for three types of dispersion-shifted fiber with graded-index core profiles1–3 (step, triangular, parabolic, and trapezoidal). Generic structural differences are that one type has a continuous matched cladding, the second has a depressed-index cladding4 relative to an outer substrate layer [Fig. 1(a)]. and the third type has up to four cladding layers with different index values5–7 [Figs. 1(b)-(f)]. This paper will emphasize the advantages of a new structure that has a narrow depressed-index trench within its cladding [Figs. 1(b), (c)]. Computer-aided modeling studies have been used to calculate tolerance curves for zero-dispersion crossover wavelengths (λ0), mode effective-index values (Δeff), cutoff characteristics, mode power profiles, and minimum cladding thickness requirements (D/d).
© 1987 Optical Society of AmericaPDF Article