Abstract: A method and apparatus for optimizing a non-ideal, real mode converter to substantially achieve the performance of an ideal mode converter. The method consists of optimizing the input linear polarization to the mode converter to balance the power in the principal modes of the mode converter at the output of the mode converter. This has the effect of maximizing the orthogonality of the output polarization states of the mode converter. The present invention also provides an electro-optical mode converter with means to adjust the orientation of the input polarization state to substantially balance the power in the principal modes at the output of the converter. In the case of an intensity modulator, the output polarization state can also be adjusted to maximize mode conversion and extinction ratio.

Abstract: A waveguide for use in polarization mode converters and polarization modulators using extrinsic strain to prerotate the principal axes and control birefringence is disclosed herein. The invention relates to the orienting of principal propagation axes in an optical waveguide by pre-stressing the waveguide, using an extrinsic stress, to re-orient the principal propagation axes from an unstressed orientation to a substantially ideal orientation. The waveguide is preferably stressed by an extrinsic strain inducer which applies a shear force to the waveguide to induce anisometry in the waveguide structure.

Abstract: An optical mode converter comprising a slow wave electrode structure and including Schottky barriers for preventing an accumulation of free carriers in the optical waveguide region of the converter. The Schottky barriers are also used for suppressing higher order modes in the waveguide. Low refractive index insulators are used to allow efficient driving of the device without hindering the impedance or the microwave index of the optical mode converter. Two-photon absorption processes are eliminated through the use of a waveguide semiconductor material having a bandgap of at least twice the photon energy of the light beam propagating through the optical mode converter.

Abstract: A semiconductor based electro-optic modulator comprising a capacitively coupled ground allowing for DC biasing of the modulator and a pre-distortion circuit for alleviating RF skin effect and for increasing bandwidth of modulator. Electrical components and functions of modulator partly located on an alumina pane. Reduction of thermally-induced stresses by connecting modulator ground to package ground via alumina pane is also disclosed.

Abstract: A method and/or apparatus for measuring current in a high voltage (HV) current carrier generates a low voltage signal proportional to the current in the HV carrier and applies this signal to an integrated-optic voltage sensor located in the HV environment adjacent to the HV current carrier to produce a modulated optical signal representative of the current being measured. The optical signal from the integrated-optic voltage sensor is conducted to a low voltage (LV) environment insulated from said HV environment and processed to provide a second electrical signal. One of the electrical signals is integrated so that an output signal of the required accuracy is available form the system.

Abstract: A voltage sensor for measuring the voltage on high voltage lines is formed by an electrically isolating-section of material with resistive shielding (RS) that structures the electric field generated by a voltage difference between the two ends of the isolating-section and provides shielding of the internal electric field from sources of electric field interference external to the voltage sensor. At least one electric field sensor is provided to sense the electric field in the isolating-section the output(s) of which is(are) used to infer the voltage difference.

Abstract: A voltage sensor for measuring the voltage on high voltage lines is formed by an electrically isolating section of dielectric material that structures the electric field generated by a voltage difference between the two ends of the isolating section and provides screening of the electric field from other electric field sources external to the isolating section. At least one electric field sensor is provided to sense the electric field in the isolating section the output(s) of which are weighted and combined to provide an accurate measurement of the voltage between the two ends. The electric field sensors are located and their outputs are combined so that error in the voltage measurement due to the influence of external electric field sources is within an acceptable range.