Polyimide waveguide components and interconnects in advanced communication systems

Reliable, low cost, compact optical components are essential to the continuing development of fiber-based communications systems. Polymers offer the potential for cheap, low temperature processing of optical components, coupled with low optical losses, and good size and index matching with optical fibers. This paper describes the use of polyimide materials for the fabrication of passive optical devices and on-chip integrated optical interconnections. A variety of basic waveguiding structures, including bends and splitters have been demonstrated, with dimensions suitable for both multimode and single mode applications. The polyimides were patterned by standard photolithography and losses were typically 0.5-1.0 dB/cm. Multimode polyimide ridge waveguides have been integrated with metal-semiconductor- metal photodetectors. Efficient coupling of the light from the guide into the detector was achieved via gaps in the underlying optical buffer layer. The integrated waveguide/detectors have been fabricated into hybrid and monolithic 4 X 4 optoelectronic switches, which offer high bandwidth and low cross-talk. This technology has also been applied to the fabrication of integrated optical/electrical transmit/receive modules for use in optically controlled phased array antenna systems.