ANNEALING EFFECTS ON GROWTH-INDUCED OPTICAL BIREFRINGENCE IN LIQUID-PHASE EPITAXIAL-GROWN BI-SUBSTITUTED IRON-GARNET FILMS

Optical birefringence in liquid-phase-epitaxial-grown (LPE) Bi-substituted iron garnet films was investigated with annealing. The optical birefringence was found to be composed of a stress-induced part and a growth-induced part. The growth-induced optical birefringence DELTA n//g was about 5 multiplied by 10** minus **4 at lambda equals 1. 15 mu m. DELTA n//g and the growth-induced magnetic anisotropy K//g disappeared after the annealing. Time constants for changes of DELTA n//g and K//g by the annealing were nearly the same and orders of a few hours at 1100-1150 degree C. A deformation of the microscopic structure around bismuth ions seems to be responsible for both DELTA n//g and K//g. The large growth-induced optical birefringence in Bi-substituted iron garnet films plays an important role to achieve high efficiency TE-TM mode conversion in magneto-optical waveguides.