A novel approach for the fabrication of planar waveguides from heavy metal oxide glasses

An extrusion process is used to fabricate preforms for the development of planar waveguides in glass ribbon format through a stretching process. The feasibility of the overall process is demonstrated using three tellurite glass compositions. The manufactured preforms present multilayered structures with the higher refractive glass layer thickness of the order of 40 μm. The longitudinal and transversal variations of the layer thicknesses are discussed with respect to waveguiding application tolerances. Advantages, limitations and improvement of the technique are also discussed. 3 mm wide multilayered planar waveguides in ribbon geometry are produced by stretching the preforms by a 1:5 ratio over a length of 400 mm. The waveguides were examined by optical and electron microscopy and no signs of crystallization or contamination are observed. Optical waveguiding is successfully assessed in 7.4 μm thick and 9 mm long film waveguides.