Scientists from Bell Labs, the research and development arm of Lucent Technologies, claim they have doubled the distance record for high-bandwidth, ultra long-distance transmission by sending 2.56 Tbits (trillion bits) of information per second over a distance of 4,000 kilometers (2,500 miles), or roughly the distance between Orlando, FL, and San Diego. The previous transmission record was 1.60 Tbits of information per second over 2,000 kilometers (1,250 miles).
"This breakthrough will ultimately enable lower capital and operational costs for our customers," contends Tim Sullivan, president of Lucent's optical networking group.
The ultra long-haul all-optical transmission record was achieved using a 64-channel DWDM system, where each channel carried information at 40 Gbits/sec. According to the company, sending a gigabit of information per second is equivalent to transmitting the information content of approximately 1,000 novels every second. Sending 40 Gbits/sec over 64 channels is equivalent to transmitting the information content of 2,560,000 novels.
The fiber-optic spans used in the Bell Labs experiment were 100 kilometers (62.5 miles) in length, typical of terrestrial networks used by service providers today. The previous distance record for a 40-Gbit/sec transmission experiment over 100-kilometer fiber spans was exactly half of the 4,000 kilometers (2,500 miles) distance record that the Bell Labs team achieved-- and the team used 64 channels, whereas the previous experiment had used 40 channels.
The transmission breakthrough was made possible using the differential phase shift keying (DPSK) method, a new coding scheme for high-capacity communications developed at Bell Labs. When coupled with other leading-edge technologies--such as extended L-band amplifiers, Raman amplifiers, forward error correction, and optimal dispersion compensation--DPSK allowed the research team to achieve error-free transmission over 4,000 kilometers (2,500 miles) for all 64 channels.
For more information about Bell Labs, visit its Web site at www.bell-labs.com. Additional details about Lucent Technologies, headquartered in Murray Hill, NJ, may be found on the company's Web site at www.lucent.com.