Yoshio Yokoyama

Dispersion flattened transmission line consisting of wide-band non-zero dispersion shifted fiber and dispersion compensating fiber module

The transmission line consisting of non-zero dispersion shifted fibers (NZ–DSFs) and dispersion compensating fiber (DCF) modules has been proposed to enable the wide-band wavelength division multiplexing (WDM) transmission. The NZ–DSFs with the effective area over 60 μm2 and the dispersion of +5–11 ps/nm/km (1500–1600 nm) have been developed to suppress the transmission penalty caused by the four-wave mixing. The DCF modules which compensate for the dispersion and the dispersion slope simultaneously have also been realized. To enhance the figure of merit (FOM) of the DCF by enlarging the absolute value of its dispersion is found to be an effective way to reduce the non-linear effects occuring in the DCF. The transmission line actually fabricated based on the optimized design exhibits an extremely low dispersion deviation of ±0.08 ps/nm/km in the C band.

Practically feasible dispersion flattened fibers produced by VAD technique

Dispersion flattened fibers (DFF) with dispersion slope of +0.026 ps/km/nm/sup 2/ and Aeff of 50 m/sup 2/ were designed and fabricated taking bending loss and their productivity into account, and attenuation as low as 0.21 dB/km was successfully realized. The fiber structure of DFF more practically feasible is theoretically explored taking A/sub eff/, bending loss performance into account as well as dispersion characteristics. The VAD technique is employed to manufacture the fiber for the advantage of productivity in mass production.

Optimum dispersion of non-zero dispersion shifted fiber for high bit rate DWDM systems

Simulations reveal that the optimum dispersion of the transmission fiber lies around +8 to +12 ps/nm/km in dense WDM transmission with a channel spacing of 50 GHz. Experiments using fibers fabricated with various dispersions support the calculations.