  A new simple entanglement measurement method is proposed for the bright EPR
beams generated from a non-degenerate optical parametric amplifier operating at
deamplification. Due to the output signal and idler modes are frequency
degenerate and in phase, the needed phase shift of interference for the
measurement of the correlated phase quadratures and anti-correlated amplitude
quadratures can be accomplished by a quarter-wave plate and a half wave plate
without separating the signal and idler beam. Therefore, phase locking and
local oscillators are avoided.
