  We evaluate the localization length of the wave solution of a random
potential characterized by an arbitrary autocorrelation function. We go beyond
the Born approximation to evaluate the localization length using a non-linear
approximation and calculate all the correlators needed for the localization
length expression. We compare our results with numerical results for the
special case, where the autocorrelation decays quadratically with distance. We
look at disorder ranging from weak to strong disorder, which shows excellent
agreement. For the numerical simulation, we introduce a generic method to
obtain a random potential with an arbitrary autocorrelation function. The
correlated potential is obtained in terms of the convolution between a Wiener
stochastic potential and a function of the correlation.
