  Classical definition of degree of polarization is expressed in quantum domain
by replacing intensities through quantum mechanical average values of relevant
number operators and is viewed as first generalization of Intensity. This
definition assigns inaccurately the unpolarized status to some typical optical
fields such as amplitude coherent phase randomized and hidden polarized, which
are not truly unpolarized light. The apparent paradoxical trait is circumvented
by proposing a new definition of degree of polarization in Quantum Optics
through second generalization of Intensity. The correspondence of new degree of
polarization to usual degree of polarization in Quantum Optics is established.
It is seen that the two definitions disagree significantly for intense optical
fields but coincides for weak light (thermal light) or for optical fields in
which occupancy of photons in orthogonal mode is very feeble. Our proposed
definition of degree of polarization, similar to other proposals in literature,
reveals an interesting feature that states of polarization of optical quantum
fields depend upon the average photons (intensity) present therein.
