Q-map method is a practical method for the design of high-speed optical communication systems. We applied this method to the optimization of periodically dispersion compensated 40 Gbit/s soliton-based TDM systems. The optimum dispersion compensation is about ±30 ps/nm and does not depend on the compensation periods. In a single-channel 640-km transmission experiment using conventional dispersion shifted fibers and 2-pieces of dispersion compensation fibers, we observed error free transmission in the wavelength range of 1.2-nm by adjusting the location of the dispersion compensation elements. The optimal channel power is about +7 dBm and the transmissible condition shows good agreement with the numerical simulations. We applied these techniques to 80 Gbit/s (40 Gbit/s, 2 PDM) transmission line design and observed error free 800 km transmission. In 40 or 80 Gbit/s/fiber systems, the dispersion-managed soliton scheme is attractive because higher SN-ratio, conventional dispersion shifted fibers and narrow band low cost amplifiers are applicable. The soliton stabilization effect enables stable long distance transmission.