Periodic dispersion compensation allows 40-Gbit/s soliton transmission

Periodic dispersion compensation allows 40-Gbit/s soliton transmission

Ultrahigh-speed soliton transmission rates have been achieved by researchers at Kodusai Denshin Denwa R&D Laboratories (Saitama, Japan), who, with a novel dispersion-management technique and initial phase modulation, have sent a 40-Gbit/s signal 8600 km over a single channel. The researchers presented their experimental work at the postdeadline session of the Third Optoelectronics and Communications Conference (Chiba, Japan). Previous long-distance transmission experiments have relied on high-speed optical modulators and electronics. In this experiment, optical time-division multiplexing first produced a 40-Gbit/s soliton signal.

The optical-fiber test setup consisted of a 140-km recirculating loop containing four spans of dispersion-shifted fiber, two spools of dispersion-compensating fiber, five erbium-doped fiber amplifiers, and an optical bandpass filter with a 5-nm bandwidth. Additional phase modulation was applied to enhance the phase modulation intrinsic to the fiber. By optimizing this modulation, a transmission distance of 8600 km was obtained with a bit-error rate of less than 1 ¥ 10-9. The researchers believe this demonstration is the longest 40 Gbit/s, single-channel transmission without using active components.