Polymeric Integrated Optical Circuits

Abstract

Polymeric integrated multimode waveguides (100 µm × 125 µm × 3 in.) have been developed on conventional FR-4 epoxy printed circuit boards (PCBs) using UV curable polymers and negative photolithographic technology. Through molecular engineering, solventless UV curable guiding and cladding materials with appropriate optical and mechanical properties have been synthesized for waveguide applications in the visible and near-infrared wavelength regions. The solventless feature of these materials made them possible to fabricate thick waveguides in single process. Novel planarization technique have been developed to overcome the problems of surface waviness of the PCBs. Multimode (>75 microns) waveguides have been fabricated to distribute control signals to multiple transmit/receive (T/R) modules on large-array radar antennas. To date, waveguide structures with straight, curved, Y-split and tap geometries have been designed and fabricated successfully on PCBs; good light intensity outputs from Y-split and multiple-tap buses were obtained. This paper will discuss the materials and optical circuit fabrication of the waveguide structures and the results of laboratory tests using the optical buses for control signal distribution to T/R modules.