  The existence of decompositions of the nonlinear integrable systems not only
permits us to establish so-called linear superposition solutions but also to
derive new nonlinear integrable coupled systems. Restricting our attention to
the single component decompositions of the potential BKP hierarchy, we obtain
that suitable linear superpositions of some decomposition solutions still
satisfy the same equations. In parallel, successful attempts are made by
multi-component decompositions of the potential BKP hierarchy to construct
linear superposition solutions and new nonlinear integrable coupled KdV-type
systems that a change of dependent variables cannot decouple.
