Abstract: A thick film bismuth doped rare earth iron garnet greater than 50 ?m in thickness with a growth-induced uniaxial anisotropy less than zero, such that all the magnetic domains in the film have their magnetization vectors in the plane of the film. A preferred embodiment comprises a film of composition Bi1.13Gd1.36Lu0.51Fe4.55Ga0.45O12. Films with such anisotropy solve the problem of devices and sensors that require a continuously varying Faraday rotation without the effective insertion losses that are inherent to discrete perpendicular domains. A similar effect can be achieved with a film of perpendicular domains by launching the light in the plane of the thick film in a non-waveguiding mode as opposed to the conventional perpendicular direction.

Abstract: Faraday rotator garnet thick films have improved specific Faraday rotations without requiring a bias magnet. Films of nominal composition BiX(EuZHo1-Z)3-XFe5-YGaYO12 are grown lattice matched to available {Gd2.68Ca0.32}[Ga1.04Mg0.32Zr0.64](Ga3)O12 substrates. The film is prepared with Z ≦0.45, which allows higher concentrations of Bi to be included in the film than prior compositions. The increased amount of Bi results in a higher specific Faraday rotations for the film. For devices such as non-reciprocal optoelectronic devices that require 45-degree rotators, the increased specific Faraday rotation results in the use of thinner films of reduced path length as well as increased crystal growth yields.