We introduce and design a novel electrooptical optical integrated tunable filter using unbalanced Mach Zehnder (M Z) interferometers in LiNbO 3.Using coupling mode equations and beam propagation method (BPM),the responses of single filter,such as the voltage and the frequency,are analyzed.In order to filtrate and route one of several frequencies,a cascaded filter is used,and all of its characters are satisfied for the all optical network(AON).