  We have observed the intensity fluctuations of the F=2 87Rb atom laser at low
output coupling rate. Theoretically, we find that the atom loss of the
condensate due to the output of atom laser leads to fluctuations of the laser
pulses, which is inherent in all state changing out-coupling such as rf and
Raman. Another reason leading to large fluctuations is the interference of
output pulses.
