This paper extends the results obtained by You-bang Zhan(1) for amplitude-c
ubed squeezing in the fundamental mode during second and third harmonic gen
erations to kth order (k > 3). It is shown that in the process of harmonic
generation in the nonlinear crystal, the cube of field amplitude of the fun
damental mode becomes squeezed if the kth harmonic is initially in a cohere
nt state. The case with the kth mode initially in the vacuum state, has als
o been studied.