An optical modulator is provided for controlling a transmission or a reflected light intensity. In the transmission mode, the separator separates the random polarized light into two polarized beams, one of the two beams are transmitted separately from the other beams. Recombination groups electro-optic phase delay when group do not change the polarization of the two beams are two beams such that the recombination at its output. These rays will lose its output as a function of the amount of voltage of the delay groups. Noh mullite having a low polarization mode spectral-off version is obtained by changing the direction of the recombined group. Noh mullite having a low polarization mode spectral-on version is obtained by a passive polarization direction rotation. Similar results may be obtained in the reflection mode in the same side of the input and output modulator. Version using the GRIN lens fiber - is adapted to modulate the light to the optical fiber or from the fiber. Apparatus of the present invention can be operated as a variable optical attenuator, an optical switch, or a high-speed modulator which is sensitive to the polarization of the input light. The preferred material of the phase retarder is a ceramic high-temperature pressure lead lanthanum zirconate (PLZT) compounds.