Thin-film-magnet magnetooptic waveguide isolator

Recent advances in thin-film-magnet and Bi-YIG film technologies have opened up the possibility of fabricating very compact magnetooptic structures. It is demonstrated for the first time that these new technologies can be brought together to make a thin-film-magnet magnetooptic isolator for use in optical packaging and integrated optical circuits. The device operates at a 1.55- mu m wavelength and uses a waveguide etched into a Bi-YIG film whose linear birefringence has been tuned to near zero at this wavelength. The Bi-YIG's magnetization is saturated by a thin ferromagnetic film. Isolation ratios of -21 dB have been obtained.< >