Experimental Study of Soliton Propagation through 40 km of Dispersion-Decreasing Fiber
A tapered optical fiber has been fabricated whose group-velocity dispersion decreases exponentially along its length at a rate closely matched to the fiber loss. We experimentally compare the propagation of picosecond solitons through this dispersion-decreasing fiber with that through a constant-dispersion fiber of the same path-averaged dispersion. For a wide range of input powers, the output pulsewidths of the dispersion-decreasing fiber are found to be as short as the input pulsewidths, whereas the output pulsewidths of the constant-dispersion fiber are significantly larger. The autocorrelation traces of fundamental solitons that have traversed the two fibers are shown in Fig. 1. There is strong evidence that a local balance between the effects of self-phase modulation and group-velocity dispersion is maintained throughout the entire length of the dispersion-decreasing fiber. At higher power levels, the evolution is dominated by intrapulse Raman scattering and cubic dispersion. Numerical simulations of the experiment are performed and are in good agreement with the experimental results.