A method of measuring birefringence in slab and ridge waveguides based on the coherent superposition of Rayleigh light scattering from TE and TM polarized modes is described and demonstrated in silica-on-silicon waveguides. A measurement accuracy of approximately 10<sup>-6</sup> has been achieved. This method is used to determine the evolution of waveguide birefringence with annealing temperature in phosphorous-doped glass waveguides. The measured birefringence increases rapidly with annealing temperatures up to 800 °C but remains unchanged for higher-temperature anneals. We interpret this threshold as the temperature above which glass can flow.
© 2003 Optical Society of America
S. Janz, P. Cheben, H. Dayan, and R. Deakos, "Measurement of birefringence in thin-film waveguides by Rayleigh scattering," Opt. Lett. 28, 1778-1780 (2003)