Please elaborate more regarding to "45% loss of pulse energy", how did you calculate it?
"the intensity of E on XOY plane also gradually decreased." I think it is reasonable: 1)its power is transfered to other wavelenth due to nonliearity; 2) the material has loss.
When you use 10 points for field profile, what is the frequency range? does it include the generated wavelengths? when the generated wavelengths have resulting intensity close to the fundamental wavelength, the ninlinearity might be too high! although Chi3 is on the order of -19, what is the source amplitude? is the index change caused by the nonlinearity a small pertubation, or on the order of 0.01 or larger? please verify before the simulation. In addition, does the nonliearity work for the source bandwidth or word onlt at one single wavelenth?
Please also check the theory and see what is its assumption.