We examine a frequency-summation process where two nondegenerate inputs interact inside a cavity via a nonlinear crystal to create a field at a higher frequency, in an attempt to find a reduction of intensity fluctuations below the shot-noise level (squeezing). We find squeezing to be possible for the intensity sum of the input modes, a theoretical maximum of near 100% reduction of the quantum noise being predicted possible. Squeezing is also found in the higher frequency, where a theoretical maximum of 50% reduction below the shot-noise level is found.

• Received 9 July 1993

DOI:https://doi.org/10.1103/PhysRevA.49.2881