  A localized non-Hermitian potential can operate as a coherent perfect
absorber or as a laser for nonlinear waves. The effect is illustrated for an
array of optical waveguides, with the central waveguide being either active or
absorbing. The arrays situated to the left and to the right from the center can
have different characteristics. The result is generalized to setups with the
central waveguide carrying additional nonlinear dissipation or gain and to the
two-dimensional arrays with embedded one-dimensional absorbing or lasing
sub-arrays.
