Abstract
The degenerate parametric oscillator operating above threshold exhibits bistability, and recent work suggests that it might also exist as a quantum-superposition state. We calculate the effect of the bistability on the two-time correlation function and the transmitted-field spectrum. The measurable steady-state probability distribution at the output of a homodyne detector is also calculated in a particular limit, in order to investigate whether one can experimentally distinguish between quantum-superposition and classical states.