  Denominators of normalized $R$-matrices provide important information on
finite dimensional representations over quantum affine algebras, and over
quiver Hecke algebras by the generalized quantum affine Schur-Weyl duality
functors. We compute the denominators of all normalized $R$-matrices between
fundamental representations of types $A_{2n-1}^{(2)}$, $A_{2n}^{(2)}$,
$B_{n}^{(1)}$ and $D_{n+1}^{(2)}$. Thus we can conclude that the normalized
$R$-matrices of types $A_{2n-1}^{(2)}$, $A_{2n}^{(2)}$, $B_{n}^{(1)}$ have only
simple poles, and of type $D_{n+1}^{(2)}$ have double poles under certain
conditions.
