Fast VOA employing electro-optically clad silica waveguide

A variable optical attenuator employing an electrooptic Kerr material as the functional cladding of a silica waveguide is shown to switch in less than 1 microsecond with an extinction ratio greater than 15 dB. The VOA is designed to operate at 70 C and the electrooptic material has a refractive index that is less than the silica waveguide at that temperature. Methods for achieving low polarization dependent loss are outlined. An electrooptically-induced half-wave plate is shown to provide polarization independent performance with polarization dependent loss less than 0.6 dB at 19 dB of attenuation.