Optical waveguides etched in 6FDA-ODA by focused ion beam

Here is described a dry process to etch optical waveguides in polymers without geometric defect of the guiding structure. The dimensions are optimized for wavelengths of around 1.5 mum used in telecommunications. The implementation of focused ion beam (FIB) appears as an emerging technology to limit the optical losses resulting from shrinking feature size of patterning with classical wet lithography. The influence of experimental parameters are reported, just as well as the resulting etching rate in a fluorinated polyimide, the 6FDA-ODA. The results are connected with the damaging mechanisms of polymers by ion bombardment. The advantages and the limits of the process are considered in view of the fabrication of a complete device. (C) 2001 Elsevier Science B.V. All rights reserved.