  Finite dimensional representations of extended Weyl-Heisenberg algebra are
studied both from mathematical and applied viewpoints. They are used to define
unitary phase operator and the corresponding eigenstates (phase states). It is
also shown that the unitary depolarizers can be constructed in a general
setting in terms of phase operators. Generation of generalized Bell states
using the phase operator is presented and their expressions in terms of the
elements of mutually unbiased bases are given.
