THE EXPERIMENTAL-STUDY OF THE EFFECT OF FIBER CHROMATIC DISPERSION UPON IM-DD ULTRA-LONG DISTANCE OPTICAL COMMUNICATION-SYSTEMS WITH ER-DOPED FIBER AMPLIFIERS USING A 1000 KM FIBER LOOP

We have evaluated the transmission performance difference of ultra-lon g distance optical communication systems with Er-doped fiber amplifier repeaters due to fiber chromatic dispersion effect. A 1000 km fiber l oop with 31 Er-doped fiber amplifiers was used for the experiments. We have changed the system zero dispersion wavelength by changing the le ngth of the normal single-mode fiber at the end of the fiber loop, and measured the bit-error-rate after transmission. Comparison of the lon gest transmission distance and the width of the 9000 km transmissible window were discussed for various system zero dispersion wavelengths. The results have shown that the difference between the gain peak wavel ength of the amplifier chain and the system zero dispersion wavelength caused degradation of the system performance, and the degree of the d egradation was almost symmetrical from the gain peak wavelength.