Degenerate parametric amplifiers with a squeezed pump

We study the effects of squeezed pump fluctuations in the degenerate parametric amplifier on signal squeezing. We find, both through semiclassical calculations and through several detailed analytic methods, that pump squeezing is responsible for two competing processes: Reduced pump phase fluctuations improve limitations to squeezing; at the same time, increased pump intensity fluctuations can lead to a ‘‘spillover’’ of pump fluctuations onto negative pump phases and a consequent reduction in signal squeezing.