  For the current realization of the affine quantum groups, a simple
comultiplication for the quantum current operators was given by Drinfeld. With
this comultiplication, we study the zeros and poles of the quantum current
operators and present a condition of integrability on the quantum current of
$U_q\left(\hat{\frak sl}(2)\right)$, which is a deformation of the
corresponding condition for $\hat{\frak sl}(2)$. We also present the results
about the zeros and poles of the quantum current operators of
$U_q\left(\hat{\frak sl}(n)\right)$.
