Characteristics of bright-squeezed light produced in a below-threshold optical parametric oscillator

We perform a theoretical analysis of steady-state solutions and quantum noise in a below-threshold optical parametric oscillator (OPO) operating as an amplifier with an input seed wave. Both the amplitude-squeezed and phase-squeezed states of the output field are considered. We take into account the intracavity nonlinear losses due to intracavity frequency doubling of the signal wave and the quantum fluctuations of the seed and pump waves. Unlike the preceding theoretical studies of the problem, we show that squeezing in bright beams produced by the OPO depends on their intensity. For the amplitude-squeezed state, squeezing strongly degrades with increasing output intensity. In contrast, one can obtain good squeezing for phase-squeezed beams of high output intensity.