Electro-optic device

摘要

An electro-optic device is disclosed, in which an RF signal electrode is used as a bias ground electrode. Thus, for Z-cut lithium niobate electro-optic crystals, there is no need to place a buried bias electrode under the RF signal electrode and over the optical waveguide. As a result, both optical and the RF wave propagation losses are reduced. In another embodiment, a buried bias electrode is placed over the optical waveguide between two buffer layers having a different electrical conductivity. The buffer layer underneath the buried bias electrode has a larger electrical conductivity than the buffer layer above the buried bias electrode. The buffer layer underneath the buried bias electrode reduces the optical loss penalty due to the buried bias electrode located above the optical waveguide, while the buffer layer above the bias electrode reduces leakage currents.

主权项

1. An electro-optic device comprising:
a substrate having an optical waveguide formed therein; an RF electrode structure for generating an RF electric field in an active section of the optical waveguide, the RF electrode structure including an RF signal electrode and at least one RF ground electrode, wherein the RF signal electrode is substantially parallel to the active section of the optical waveguide and is disposed above the active section of the optical waveguide; a buffer layer between the signal RF electrode and the optical waveguide, disposed over the substrate in at least a partial contact therewith; and a bias electrode structure for generating a biasing electric field in the active section of the optical waveguide, the bias electrode structure comprising a first bias signal electrode disposed substantially parallel to the active section of the optical waveguide between the RF ground electrode and the RF signal electrode and adjacent to one side of the active section of the optical waveguide, wherein the bias electrode structure is free of any electrodes at least partially disposed directly under the RF signal electrode, whereby the biasing electric field is generated in the active section of the optical waveguide by the first bias signal electrode with the RF signal electrode as a bias ground electrode.