March 16, 2006 Tokyo, Japan -- Oki Electric Industry announced that it has achieved experimental 160-Gbit/sec data transmission over a distance of 635 km, in a field trial conducted as part of a project consigned by Japan's National Institute of Information and Communications Technology (NICT).
For the trial, Oki used an optical testbed provided by Japan Gigabit Network II (JGN II). In the experiment, "high-vision video" transmission was conducted by connecting to a photonic network provided by Japan's University of Electro-Communications. The university generated a 10-Gbit/sec optical signal including the high-vision video data; this transmission was then boosted to 40-Gbit/sec through time division multiplexing provided by Anritsu, which also assisted in extracting data from the experiment. The 40G signal was then inputted into Oki's individual modulation optical time division multiplexing module, which converted the signal into 160-Gbit/sec optical data.
Oki's prototype 160-Gbit/sec optical transceiver was first exhibited at the 2004 International Optoelectronics Exhibition in an experimental 120-km fiber-optic transmission. According to Oki, to create a data signal for 160-Gbit/sec transmission, an optical signal would ordinarily be multiplexed from 40 Gbit/sec to 160 Gbit/sec by using four passive planar lightwave circuit (PLC) pulse interleavers. However, the company's time division multiplexing module includes 4 modulators to create four 40-Gbit/sec optical signals; by multiplexing the four signals, the module is able to output one 160-Gbit/sec optical signal.Â
Notable as a real-world environment with changing temperatures, JGN II's testbed is a singlemode optical fiber (63.5 km x 10 fiber cables) installed between Kyoto's Open Laboratory and Osaka's Dojima Relay Station. At each connection point an optical amplifier similar to a commercially used relay station for 10-Gbit/sec data transmissions and a dispersion compensation fiber are installed. JGN II says the test bed is "structured to increase the transmission distance by changing the number of turn-back times."
In the field trial, Oki used a 254-km transmission route with two turn-backs to achieve error-free transmission of signal evaluation data simultaneous with the high-vision video. Transmission distance was increased to 635 km by raising the number of turn-backs to five.
"The module used in this experiment reduces optical coupling loss by half, is one third the previous size, and offers increased usability," says Harushige Sugimoto, senior vice president and CTO at Oki Electric. "The success of the 635-km field trial proves [the module] can be used for backbone lines such as the [500-km] super high-speed optical [link] between Tokyo and Osaka, which is 16 times higher in speed than the 10-Gbit/sec systems that are commercialized."Â
The experiment, hosted by NICT as part of a project entitled "Research and Development on Ultra-high-speed Backbone Photonic Network Technologies," took place in December 2005 in cooperation with the Research Promotion Council of Keihanna Info-Communication Open Laboratory.
"160-Gbit/sec optical transmission [represents] the next generation of super high-speed optical transmission technology to be commercialized after 2010," concludes Sugimoto. "We will continue to analyze the results we have obtained and will develop a 160-Gbit/sec optical transceiver for real data transmission."Â Â