In this paper, we aim to propose an optical structure for realizing half-adder operation without using the nonlinear Kerr effect. Constructive and destructive interference of optical beams is the main working mechanism of the proposed structure. The phase difference required for the destructive interface will be created by choosing different lengths for the input waveguides of the XOR gate. For the proposed structure, the on-off contrast ratios for SUM and CARRY are 9.77 dB and 6.98 dB, respectively. Also, the delay time and footprint of the proposed structure are about 4 ps and 1056 μm<sup>2</sup>, respectively.