  We investigate entanglement in the above-threshold Optical Parametric
Oscillator, both theoretically and experimentally, and discuss its potential
applications to quantum information. The fluctuations measured in the
subtraction of signal and idler amplitude quadratures are $\Delta^2 \hat
p_-=0.50(1)$, or $-3.01(9)$ dB, and in the sum of phase quadratures are
$\Delta^2 \hatq_+=0.73(1)$, or $-1.37(6)$ dB. A detailed experimental study of
the noise behavior as a function of pump power is presented, and discrepancies
with theory are discussed.
