  The time evolution from coherent states to squeezed states of high density
excitons is studied theoretically based on the boson formalism and within the
Random Phase Approximation. Both the mutual interaction between excitons and
the anharmonic exciton-photon interaction due to phase-space filling of
excitons are included in consideration. It is shown that the exciton squeezing
depends strongly on the exciton density in semiconductors and becomes smaller
with increasing the latter.
