  In this doctoral thesis we have studied the quantum properties of several
models which have been classified as statical and dynamical systems. The first
part has been devoted to investigate the properties of the statical models
including the superposition of squeezed displaced number states with and
without thermal noise. Also we have developed a new type of multidimensional
squeeze operator including two different squeezing mechanisms. In the second
part the dynamical models were given to show the interaction between modes in
the nonlinear optical coupler.
