Possible refractive index profiles and other major parameters of the small dispersion single mode fiber (SDSMF) with ±2 ps/km/nm dispersion are presented in this paper, and their applications are discussed. Results show that SDSMF is suitable for high speed, WDM+EDFA systems, both for its non zero dispersion to effectively suppress the four wave mixing (FWM) effect, and small dispersion to avoid severe dispersion induced degradation. When dispersion compensation is employed in the sequence of ITU-T G.652 conventional single-mode fiber (CSMF) and negative SDSMF between two adjacent in-line amplifiers in a 10×10 Gb/s, 10 stage EDFA system, it offers the advantage of not only reducing the required system bandwidth from 16.2 nm to 9.4 nm at tolerable penalties caused by dispersion and FWM, but also making it possible for equal channel-spacing transmission which significantly simplifies system design.