The stress in cladding layers has significant impact on the SOI waveguide birefringence. Both the stress levels in the films and the thickness of the films can be used to adjust the waveguide birefringence. This method gives another degree of freedom in waveguide birefringence control, and in waveguide geometry design which also needs to meet the requirements for single-mode and low loss operation.

2003 IEEE LEOS Annual Meeting Conference Proceedings
Department of Electronics

Xu, D.-X. (D. X.), Cheben, P. (P.), Dalacu, D. (D.), Janz, S. (S.), Picard, M.-J. (M. J.), Tarr, N.G, & Ye, W.N. (2003). Control and compensation of birefringence in SOI waveguides. In Conference Proceedings - Lasers and Electro-Optics Society Annual Meeting-LEOS (pp. 590–591).