Nonlinear optical processes producing three-fold entanglements via x(2) and x(3) material

It is demonstrated that three-fold entangled states could lead to photon duplication as well as measurement of photon numbers of the first kind. Nonlinear optical schemes using chi(()2) and chi((3)) material for realizing such systems are suggested. Weak input power signals and fast response photodetectors axe required for ideal operations. A criterion of incorrect operation of photon number cloning is also introduced and the operations of these realizations are studied for high-speed photodetectors and coherent state input field.