  Quantum fluctuation and quantum entanglement of the pump field reflected from
an optical cavity for type II second harmonic generation are theoretically
analyzed. The correlation spectra between the quadratures of the reflected
subharmonic fields are interpreted in terms of pump parameter, intracavity
losses and normalized frequency. Large correlation degrees of both amplitude
and phase quadratures can be accessed in a triple resonant cavity before the
pitchfork bifurcation occurs. The two reflected subharmonic fields are in an
entangled state with the quantum correlation of phase quadratures and
anticorrelation of amplitude quadratures. The proposed system can be exploited
to be a new source generating entangled states of continuous variables.
