  Ocean rogue waves (RW) -huge solitary waves- have for long triggered the
interest of scientists. RWs emerge in a complex environment and it is still
dubious the importance of linear versus nonlinear processes. Recent works have
demonstrated that RWs appear in various other physical systems such as
microwaves, nonlinear crystals, cold atoms, etc. In this work we investigate
optical wave propagation in strongly scattering random lattices embedded in the
bulk of transparent glasses. In the linear regime we observe the appearance of
RWs that depend solely on the scattering properties of the medium.
Interestingly, the addition of nonlinearity does not modify the RW statistics,
while as the nonlinearities are increased multiple-filamentation and intensity
clamping destroy the RW statistics. Numerical simulations agree nicely with the
experimental findings and altogether prove that optical rogue waves are
generated through the linear strong scattering in such complex environments.
