A systematic model for all-optical full adder as well as full subtractor is proposed based on principle of Mach Zehnder Interferometer and using Semiconductor Optical Amplifier (MZI-SOA) configuration. MZI plays a role for ultra fast alloptical signal processing, here the non-linear property of SOA are properly utilized for designing the full adder as well as full subtractor. In this model the full adder as well as full subtractor can be effectively designed by properly selecting output terminals of MZI-SOA component. The design is implemented with the help of OptiSystem software which is one of the powerful software for analyzing Optical components. The proposed mode shows design performance of full adder as well as full subtractor in optical domain and it seems to be future wireless technology.