Covers of D-type Artin groups

We study certain quotients of generalized Artin groups which have a natural map onto D-type Artin groups, where the generalized Artin group A(T) is defined by a signed graph T. Then we find a certain quotient G(T) according to the graph T, which also have a natural map onto A(D_n). We prove that G(T) is isomorphic to a semidirect product of a group K^(m,n), with the Artin group A(D_n), where K^(m,n) depends only on the number m of cycles and on the number n of vertices of the graph T.