  Higher order nonclassical properties of fields propagating through a
codirectional asymmetric nonlinear optical coupler which is prepared by
combining a linear wave guide and a nonlinear (quadratic) wave guide operated
by second harmonic generation are studied. A completely quantum mechanical
description is used here to describe the system. Closed form analytic solutions
of Heisenberg's equations of motion for various modes are used to show the
existence of higher order antibunching, higher order squeezing, higher order
two-mode and multi-mode entanglement in the asymmetric nonlinear optical
coupler. It is also shown that nonclassical properties of light can transfer
from a nonlinear wave guide to a linear wave guide.
