Abstract: A structure and a corresponding method for producing a permanent electric biasing field in an electrooptical device. Electrodes are embedded in an insulating layer formed over the device, which includes a substrate of electrooptical material and an optical waveguide formed in the substrate. The electrodes are electrostatically charged and encapsulated in the insulating layer, to produce the desired electric field without the need for an external voltage source.

Abstract: An electrooptical polarization mode converter that operates independently of the wavelength of the light being converted. The converter includes a titanium in-diffused waveguide formed in a lithium niobate substrate, but light is propagated in the direction of the optic axis, rather than perpendicular to it as in prior devices. Both transverse-electric (TE) and transverse magnetic (TM) modes experience the same material refractive index, and mode switching can be effected with only minimal phase velocity mismatch, by applying a bias voltage across the waveguide. The phase velocity mismatch is corrected electrooptically by applying an orthogonal electric field to the waveguide, and mode switching and phase velocity correction effects can be controlled independently.

Abstract: An optical waveguide device for multiplexing and demultiplexing transverse magnetic (TM) and transverse electric (TE) polarization modes. The device has two waveguides, having first and second coupler segments in close proximity to each other, but with the second coupler segment capable of supporting only one polarization mode. When both TE and TM modes are introduced into the first coupler segment, one mode is coupled completely across to the second coupler segment, but the mode not supported in that segment remains in the first segment and is transmitted to an output port. In the illustrative embodiment of the invention, this selective coupling of the polarization modes is achieved by choosing a narrow width for the second coupling segment, such that the TE polarization mode is not supported but the TM polarization mode is. The interaction length of the coupling segments is selected to produce complete coupling of the TM energy to the second coupling segment.