In a Cu:KNSBN crystal, the self pumped phase conjugation changes from the cat′s mechanism to stimulated backscattering and four wave mixing mechanism as wavelength of the pump beam being changed from 514.5 to 488 nm. After it is formed, the self pumped phase conjugation at 488 nm changes from slow fluctuation to a quasi sable state gradually in about 400 seconds, while the phase conjugation at 514.5 nm is always in an irregular flutuation state.