  In this paper, we will constrain the operator ordering ambiguity of
Wheeler-DeWitt equation by analyzing the quantum fluctuations in the universe.
This will be done using a third quantized formalism. It is expected that the
early stages of the universe are dominated by quantum fluctuations.
Furthermore, it is also expected that these quantum fluctuations get suppressed
with the expansion of the universe. We will show that this desired behavior of
quantum fluctuations could be realized by a wide ranges of the factor ordering
parameters. We will examined two different cosmological models, and observe
that a similar range of factor ordering parameters produces this desired
behavior in both those cosmological models.
