An optical accelerometer based on antiresonant reflecting optical waveguides is presented. The design consists on a quad beam structure where two waveguides are placed on the frame of the accelerometer, while a third is placed over the proof mass. When an acceleration is applied, a misalignment between the three waveguides is immediate, causing a reduction in the output power. If the passivation layer is not considered, simulations predict a nearly symmetrical behavior for positive and negative accelerations, with an optical sensitivity of 2.3 dB/g. Experimental and simulation confirm that passivation modes produce a reduction in the optical sensitivity for positive acceleration values, resulting in an asymmetrical response of the accelerometer.