  We have made current-voltage (IV) measurements of artificially layered
high-$T_c$ thin-film bridges. Scanning SQUID microscopy of these films provides
values for the Pearl lengths $\Lambda$ that exceed the bridge width, and shows
that the current distributions are uniform across the bridges. At high
temperatures and high currents the voltages follow the power law $V \propto
I^n$, with $n=\Phi_0^2/8\pi^2\Lambda k_B T+1$, and at high temperatures and
low-currents the resistance is exponential in temperature, in good agreement
with the predictions for thermally activated vortex motion. At low
temperatures, the IV's are better fit by $\ln V$ linear in $I^{-2}$. This is
expected if the low temperature dissipation is dominated by quantum tunneling
of Pearl vortices.
