In this work, V-shaped liquid crystals are proposed for phase modulation optical devices. The aim is to measure the relationship between phase shift and the applied voltage by an experimental set-up based on an interferometer. The optical retardation of the liquid crystal medium could then be determined simply by measuring the phase difference of the waves of the two arms. By supplying a voltage, the liquid crystal molecules are reoriented and the effective refractive index of the liquid crystal changes. Preliminary results show that the devices may be used such as phase modulators, but the phase modulation is polarization sensitive.