Fujitsu says it has collaborated with NTT Communications Corp. on a successful field test of coherent 100-Gbps DWDM transmission via a commercial fiber-optic cable between Tokyo and Osaka. The test clears the way for full network construction using the 100-Gbps DWDM systems.

While Fujitsu has implemented coherent 100-Gbps DWDM systems outside of Japan (see, for example, “Mid-Atlantic Crossroads uses Fujitsu FLASHWAVE 9500 for 100-Gbps network”), the field test opens the door for its first deployment in Japan. The test was conducted using dispersion-shifted fiber in the L-Band, which is often used in Japan for long-haul transmissions.

The field test simulated real-world situations, such as fiber-optic cable changes in accordance with transmission-circuit route changes and adding/removing wavelengths. The results confirmed that a quality sufficient for commercial operation could be achieved at 8 Tbps (100 Gbps x 80 multiplexed wavelengths). The test also demonstrated that the system could compensate automatically when adding chromatic dispersion and polarization mode dispersion to actual transmission circuits.

Digital coherent transmission technology makes use of results achieved in two previous research projects, "R&D on High-speed Optical Transport System Technologies" and "R&D on High-speed Edge Node Technologies," which were supported by the Ministry of Internal Affairs and Communications.