Fabrication Of Polymer Thin Film Waveguides For Thermo-optic Switches

Optical switches are not only key devices in optical interconnection, but also one of the important elements that would affect the performance of All Optical Network. Research works on the advantages of polymer's properties and the fabrication of polymer thermo-optic switches are thus of crucial significance. This paper emphasized on the basic techniques of thermo-optical switches fabrication: polymer thin film planar waveguides fabrication. The contents of this paper are listed below:(1)The principle of the synthesis of polyimide materials was introduced, and the preparation procedure was thoroughly described.Advanced polymer thin films for waveguides were prepared through spin coating. Some process parameters, as solution concentration, spin speed, volatility and vapor absorbing ability of solvents, were discussed on their effects on the qualities of the spin coated polymer thin films. Possible conditions that may lead to fault on films were analyzed, and some characters of the films as thickness, refractive index, infrared absorbing spectrum and topography were tested to optimize the spin coating.A layer of Al film was deposited on the prepared polymer thin film through magnetron sputtering. The working principle of the magnetron sputtering was briefly introduced.The micrograph was imposed on the Al layer through photolithography, and the Al layer was etched by 90℃ concentrated phosphoric acid. The technical procedure was thoroughly described and possible factors that may lead to faults were analyzed to improve the precision of the imposed fine pattern.The polymer thin films were etched by the ICP (inductive coupled plasma) etching to make thin film planar waveguides. The gas used in the reactive chamber is oxygen and the prepared Al pattern was used as mask. The waveguides acquired were tested and the instrument we used in experiment was introduced. Before the analysis of factors that would affect the etching process, the working principle of ICP was introduced. In this paper, the fabrication procedure of the polymer thin film planar waveguides was thoroughly described and analyzed through large amount of experiments. We finally fabricated satisfactory polymer thin film planar waveguides for thermo-optic switches. This would be a good beginning for further investigation into the fabrication of thermo-optic switches, and would be of great practical value.