We report a design for a small-residual-dispersion fiber system suitable for all wavelengths in the range of 1480 to 1610 nm, which covers the entire S to L bands. It consists of a small-relative-dispersion-slope fiber (SRDSF) with a flat modal field over the central part of the core, and the corresponding dispersion-compensating fiber (DCF). The SRDSF has mode field diameter (MFD) <10 μm at wavelength λ0=1.55 μm, leading to the large effective area (Aeff≈ 95 μm2) required to reduce nonlinear effects, and dispersion 9.5 ps/(km nm) with small relative dispersion slope <0.003 nm−1 at λ0=1.565 μm. The DCF, which is based on the dual-core coaxial configuration, has large negative dispersion [ ≈−248 ps/(km nm) at λ0=1.565 μm], leading to a large figure of merit (FOM). The dispersion slopes of these fibers are so adjusted that a small length of DCF will compensate the accumulated dispersion in the SRDSF simultaneously at all wavelengths in the range of 1480 to 1610 nm. The maximum values of the effective dispersion of the fiber system and its slope are about ±0.2 ps/(km nm) and ±0.03 ps/(km nm2), respectively, in the entire wavelength range of 1480 to 1610 nm.