Laser Direct Writing of Optical Interconnects in Polyimides and Sio 2 :TiO 2 Coatings

Commercially available polyimides and SiO 2 :TiO 2 coatings are experimentally studied for their potential application in optical guided-wave interconnect networks. Optical properties are measured, including transmission spectra, refractive index and loss, with the aim of determining the materials most suited for this application. On the most promising candidates, direct writing of strip waveguides with Ar-ion laser at 514.5 and 457.9 nm was performed. Localized thermal curing by writing with speeds up to 250 microns per second allows the achievement of multimode guiding structures. Light propagation loss measurements reveal that attenuation in strip waveguides is of the same order as in slab structures of the same material, typically 5-10 dB/cm at 633 nm.