We designed all-optical AND, OR, NOT, and XOR logic gates based on photonic crystals configuration. This configuration consists of a bend waveguide with single embedded rod and a T-branch waveguide. The proposed structure does not consist of nonlinear rods. The constructive and destructive interferences between incident and reflected waves have caused to switch the output of gate. The gate contains a two-dimensional square lattice made of dielectric rods embedded in the air. It operates at communication wavelength of 1550 nm when the lattice constant of structure is 500 nm. Simplicity of the proposed logic gates provides the possibility of application in practical logic gate and large-scale optical integration.