US Patent 9411176 Oxide capacitor electro-optical phase shifter

An electro-optical phase shifter to be located in an optical waveguide may include a rib of a semiconductor material extending along a length of the optical waveguide and a control structure configured to modify a concentration of carriers in the rib according to a control voltage present between first and second control terminals of the phase shifter. The control structure may include a conductive layer covering a portion of the rib and electrically connected to a first of the control terminals. An insulating layer may be configured to electrically isolate the conductive layer from the rib.