Packaging and testing high-speed electrooptic polymer modulators

Electrooptic polymer modulators demonstrate ultra-high frequency response to 110 GHz at chip level. To interconnect these integrated polymer waveguide devices to fiber-optic networks and to fully use their ultra-wide bandwidth capacity, a packaging technology that includes optical interfaces to standard fibers, electrode transitions to wideband coaxial cable connectors, and a stable mechanical enclosure is required. This paper summarizes TACAN's efforts in high-speed electrooptic polymer modulator chip interfacing package. Fiber-to-waveguide pigtailing, mode mismatch loss reduction, and the optimization of extinction ratio are important considerations for optical interfaces. Due to materials limitations and the low driving voltage requirement, the waveguide mode size is often much smaller than that of a standard fiber which results in large mode mismatching loss. A fiber mode size conversion coupler has been developed to reduce the mode mismatching loss. For microwave interfaces, the emphasis is on the electrode to coaxial cable connector transitions that include the use of commercial components and the test of connectorized circuits. The packaged electrooptic modulators were tested for their performance characteristics. Connector-to-connector frequency response of the electrode circuits, analog and digital signal transmissions, long-term halfwave voltage stability, and DC bias stability have been tested using packaged electrooptic modulators.