Electro-optical response of a liquid-crystalline fiber coupler

Abstract

The electro-optical properties of a thin layer of nematic liquid crystal, sandwiched between two side-polished single-mode optical fibers and flanked by electrodes, are investigated by documenting the response of the resulting fiber coupler to electric fields of different frequencies and amplitudes. It is found that similar coupling states (corresponding to similar states of the liquid crystal) are created at every driving frequency if the correct voltage level (above a threshold dependent on the coupling state) is selected. The presence of certain resonance peaks in the frequency response of the liquid crystal (to our knowledge not before observed) is explained phenomenologically in terms of orientational standing-wave patterns between the electrodes.