All optical logic gates NOT, NAND and AND gates using two photon absorption in silicon wire waveguide is proposed. Due to use of ultra short pulse there is negligible free carrier absorption effect and hence the operating speed of the gates is very high and has potential application in photonic processing. NAND gate is universal one and thus one can perform any logical operation using this. The device silicon wire waveguide (Si wire WG) requires low energy pulse (few PJ) and is ultra fast one. Key words: Silicon wire waveguide, two photon absorption, logic gate, photonic integration.