We examine a frequency-summation process where two nondegenerate input
s interact inside a cavity via a nonlinear crystal to create a field a
t a higher frequency, in an attempt to find a reduction of intensity f
luctuations 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 p
ossible. Squeezing is also found in the higher frequency, where a theo
retical maximum of 50% reduction below the shot-noise level is found.