Abstract

We report here (the fist, to the best of our knowledge) demonstration of massive WDM, over transoceanic distances, in multiples of 10 Gbit/s. The vital ingredients to this success were first, solitons, second, sliding-frequency guiding filters, and third, the use of "dispersion-tapered" fiber spans between amplifiers, i.e., spans for which D ( 2 ) tends to follow (here in step-wise approximation), the same exponential decay profile as does the signal energy. Although the first two ingredients and their benefits are by now well known [l-31, the third, at least in this context, is both nove1 and vital. As we have detailed elsewhere [4], first, without dispersion tapering, pseudo phase matching allows four wave mixing products from soliton-soliton collisions to grow uncontrollably and hence to cause intolerable timing and amplitude jitter. (In earlier experiments without dispersion tapered spans, only a 2 x 10 Gbit/s WDM could be done reasonably well; beyond that point, the error-free distances dropped off very quickly with increasing numbers of channels.) Second, dispersion tapering lifts the restriction Lc01122LV that obtains with spans of constant 0 [5], which in turn limits the maximum allowable channel spacing. (L,I~ and L, are the collision length and spacing between amplifiers, respectively.)

© 1996 Optical Society of America