ANAHEIM, CA and MURRAY HILL, NJ -- Scientists from Bell Labs say they have doubled the distance record for high-ban...
March 25, 2002
ANAHEIM, CA and MURRAY HILL, NJ — Scientists from Bell Labs say they have doubled the distance record for high-bandwidth, ultra long-distance fiber optic transmission.
The team — the R&D arm of Lucent Technologies — is said to have sent 2.56 terabits (trillion bits) of information per second over a distance of 4000 kilometres (2500 miles), roughly the distance between Orlando, FL, and San Diego, CA. The previous transmission record was 1.60 terabits of information per second over 2000 kilometres (1250 miles).
“This breakthrough will ultimately enable lower capital and operational costs for our customers,” said Tim Sullivan, president of Lucent’s optical networking group.
This new transmission record was achieved using a 64-channel dense wavelength division multiplexing (DWDM) system, where each channel carried information at 40 gigabits per second. The DWDM technique makes it possible to send multiple streams of information down the same optical fiber.
The company says scientists used a differential phase shift keying (DPSK) method — a new coding scheme for high-capacity communications, developed at Bell Labs. When coupled with other Bell Labs technologies (such as extended L-band amplifiers and optimal dispersion compensation), DPSK let the team achieve transmission over 4,000 kilometres for all 64 channels, each of which had a signal of 40 gigabits per second.