Abstract: Provided are an enhanced structure of a coplanar waveguide that is a kind of transmission line used for optical communication for radio frequency (RF), and an optical communication module employing the same. While having a basic structure including a conductive strip and ground strips at both sides of the conductive strip on a dielectric substrate, the coplanar waveguide has the structure in which metal patterns of a portion of the conductive strip located around points where an RF propagation direction is changed and of a portion of an inside ground strip are removed to make electrical lengths of an outside ground strip and the inside ground strip similar each other. Using the coplanar waveguide, it is possible to fabricate an optical module that has an optimized RF characteristic and also can freely change an RF propagation direction of several tens GHz, without an additional process.

Abstract: Provided is a semiconductor optical modulator device in which a resistor for impedance matching is integrated in a device in order to improve performance and to reduce cost during the fabrication of an ultra high speed optical modulator module. A doped layer in an epitaxial layer of the optical modulator device is used as a resistor for impedance matching. According to this method, it is possible to more easily realize an optical device compared with optical device fabrication processes in which additional resistors are used in the outside and the inside of the device for impedance matching.