Growth-Induced Optical Birefringence in LPE-Grown Bi-Based Iron Garnet Films

Abstract

A growth-induced optical birefringence has been observed in Bi-based iron garnet films grown by LPE method. The lattice misfit dependence of the birefringence, which is estimated from the phase mismatch between TE and TM modes in the garnet thin film waveguide, shows the existence of optical anisotropy that can not be attributed to the stress in the film. This birefringence is ascribed to the growth-induced one because its magnitude is reduced by annealing. The sign of the growth-induced birefringence is positive ( n T M - n T E >0), and it is favorable to achieve complete TE-TM mode conversion.