Abstract

Selective photobleaching has recently been suggested as a technique for fabricating channel waveguides in electrooptic (EO) polymers.^1,2 Both active and passive integrated-optical devices were fabricated to evaluate this technique. First, three layers of polymer are spin-coated on metallized silicon: acrylate buffer/active organic polymer/acrylate buffer. Next, the top metal layer is deposited. The stack is then poled to induce a nonzero EO coefficient. Finally, the top electrode is patterned as a mask for selective photobleaching of channel waveguides. The exposure to ultraviolet light lowers the index of refraction in the exposed regions of the organic layer. The wafer is then cleaved and ready for endfire testing, which was done at both 0.8 μm and 1.3 μm. The device structures included straight waveguides, angled splitters and combiners, s-bend splitters and combiners, directional couplers, and six-port evanescent couplers. Waveguide widths ranged from 1 μm to 7 μm, and the model characteristics of each size waveguide were evaluated. Overall loss was measured for each type of device, as well as splitting ratios for the branching devices, and switching voltages for the coupling devices. More than one hundred devices were tested, demonstrating that photobleaching is a viable waveguide fabrication technique for certain EO polymers.

© 1991 Optical Society of America