Patterning polymer surfaces by laser ablation for integrated optics

Polymers may be ablated photochemically and photothermally. We restrict here on the photothermal laser beam ablation technique in order to produce patterns for integrated optics. The edges of the ablated material have to be smooth in order to avoid additional optical scattering. For poly-(methylmethacrylate) (PMMA) optical waveguide patterns are recorded forming multimode lightguides. Three different types of lightguides are discussed. Smooth edges for the use as total internal reflection mirrors have been made. With the CO₂ laser multimode patterns have been produced. They appear useful for applications with polymer optical fibres. For the recording of smaller patterns fitting to optical monomode fibres 248 nm excimer laser radiation was used. We report on the production of V-type grooves in PMMA suitable for the mount of optical single mode fibres for fibre-chip coupling. Those grooves can be controlled in their form, in their depth and their width with a resolution of better than 0.1 μm/pulse