  Quantum noise suppression and phase-sensitive modulation of continuously
variable in vacuum and squeezed fields in a hybrid resonant cavity system are
investigated theoretically. Multiple dark windows similar to electromagnetic
induction transparency (EIT) are observed in quantum noise fluctuation curve.
The effects of pumping light on both suppression of quantum noise and control
the widths of dark windows are carefully analyzed, and the saturation point of
pumping light for nonlinear crystal conversion is obtained. We find that the
noise suppression effect is strongly sensitive to the pumping light power. The
degree of noise suppression can be up to 13.9 dB when the pumping light power
is 6.5 Beta_th. Moreover, a phase-sensitive modulation scheme is demonstrated,
which well fills the gap that multi-channel quantum noise suppression is
difficult to realize at the quadrature amplitude of squeezed field. Our result
is meaningful for various applications in precise measurement physics, quantum
information processing and quantum communications of system-on-a-chip.
