Measurement of modal birefringence in optical waveguides based on the Mach-Zehnder interferometer.

A method for measuring the birefringence in planar waveguide circuits is theoretically proposed and validated. The method is based on the Mach-Zehnder interference and by measuring the spectral shift due to orthogonal polarization states. The birefringence of a silica waveguide is measured to be 2.33 x 10-4 at nearby 1550 nm. In addition, the birefringence variations with the wavelength and its dependence on the external stress are investigated with the proposed method experimentally. The results in measuring birefringence demonstrate a high accuracy with the order of 10-5, a wide dynamic range from 10-5 to 10-3, and a characteristic of multi-wavelength evaluation. [ABSTRACT FROM AUTHOR]