Fabrication and optical properties of the multilayered waveguide made by photobleaching process

Abstract

In the field of optical interconnect technology, many works are in progress for polymer material that is more inexpensive in terms of material and processes than conventional quartz optical waveguides. We had developed a novel type of material for optical waveguides consisting polysilane, silicone and photosensitizer. This material named "GlasiaWG (TM) can decrease its refractive index by UV irradiation. Using this photobleaching phenomenon, we can fabricate optical waveguides that have flat surfaces by simple process without chemical etching. In this work, we have developed multilayered optical waveguides that enable to make two-dimensional multichannel connectors for multimode optical interconnects. To fabricate multilayered optical waveguides, we prepare glass substrates whose thickness are 150μm and two kinds of GlasiaWG (TM) having different refractive indexes respectively. At first GlasiaWG (TM) having a higher refractive index is coated on the glass substrate, and then the coated film is irradiated by UV-light with a photomask to create core and side cladding parts. After baking the core layer at 250 degrees C another GlasiaWG(TM) with a lower refractive index is coated on the core layer and baked at 250 degrees C. One-layer optical waveguide is completed for one unit. After accuracy alignment, four units of optical waveguides are laminated by heating at 80 degrees C and pressing with 50kg/cm2, and diced to proper size pieces. Eventually four-layered optical waveguides are fabricated. Flat surfaces made by photobleachig process and adhesive properties with glass enable to fabricate multilayered optical waveguides. This fabrication is a feature of GlasiaWG^TM.