Avanex Corporation

Antonino Nespola

Valerio Pruneri

Simone M Pensa

A coplanar integrated optical waveguide electro-optical modulator comprises a substrate ( ) of an electro-optic material, at least two optical waveguides ( ) integrated in the substrate in correspondence of a surface ( ) thereof, and an electrode system ( - ) arranged on the surface for applying a modulating electric field to the waveguides suitable for causing a modulation of a refractive index of the two waveguides in a device modulation region ( ). The waveguides are formed, for at least a section thereof ( ) in the device modulation region, in respective substrate regions ( ) which have electro-optic coefficients of opposite sign along an axis transversal to the waveguide sections, so that a modulating electric field of same direction and orientation in the waveguide sections causes refractive index modulations of opposite sign in the waveguide sections. Chirp-free coplanar waveguide modulators and single-drive double coplanar strip modulators can thus be obtained.

Coplanar integrated optical waveguide electro-optical modulator

A high-speed external optical modulator formed on a lithium niobate substrate has a diffused optical waveguide, a surface buffer layer, and electrodes for applying modulating RF energy. The electrodes are electroplated in at least two steps, resulting in a top co-planar waveguide structure lying on a second one. Low driving voltage is achieved through selection of the width, position, and dimension of the lower hot and ground electrodes. The upper ground electrodes and, preferably, also the upper hot electrode, are narrower in width than the corresponding lower electrodes, which helps to provide good velocity matching, good impedance values, and low electrical losses.

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Moncalieri, Italy

Antonino Nespola