Abstract

In ultralong distance soliton transmission, the limit to single-channel bit rate is set by jitter in pulse arrival times. That jitter can be reduced through the use of narrow-band frequency-guiding filters, periodically distributed along the transmission line^1,2. Because extra gain must be employed to offset the loss the solitons experience from passage through the filters, however, with fixed-frequency filters, amplifier spontaneous emission noise rises exponentially with distance. This tends to put a limit on the maximum useable filter strength, and hence on the practically attainable reduction in jitter. In earlier transmission experiments³, for example, the filter producing the minimum error rate was just strong enough to reduce the standard deviation in the timing jitter by about a half, in the trans-Pacific distance of ~10 Mm (10,000 km). In a recent paper⁴, however, we have shown how that limitation can be overcome by gradually translating the peak frequency of the filters with distance along the transmission line. That is, with such "sliding- frequency guiding filters," we create a transmission line that is opaque to noise for all but a small final fraction of its length, yet remains transparent to solitons. In this paper, we report the first experimental demonstration of high bit rate transmission using such strong, sliding-frequency filters.

© 1993 Optical Society of America