In recent years, as demand for high speed communication with advanced technology is increasing in optical communicat ion,so optical logic gates are being widely investigated for various applications in signal processing such as optical binary adder, optical counters, optical time division mult iplexing and low power computing etc. In the proposed work we have demonstrated the implementation of different logic gates such as AND, OR, XOR, XNOR, NAND and NOR which are the basic components to design any combinational and sequential circuits using Mach Zehnder Modulator (MZM). The MZM minimizes the effect of dispersion and provides the fast switching for high speed optical communicat ion. The MZM is used for controlling the amplitude of optical wave by applying voltage that introduced phase shift in the wave passing through the arm. This allows us to switch the output power from high to low or vice - versa (from login 1 to 0 or vice-versa). The proposed optical logic gates using MZM has low complexity and high scalability.