Strong magneto-optical enhancement in highly Ce-substituted iron garnet films prepared by sputtering J. Appl. Phys. 70, 7065 (1991); 10.1063/1.349786Strong magneto-optical enhancement in highly Ce-substituted iron garnet films by sputtering (abstract)This article describes the demonstration of magneto-optic channel waveguides in Ce-substituted yttrium iron garnet which has a very large Faraday rotation. The rib waveguides are successfully produced by employing a new etching technique, which is a reactive ion etching method using BCls gas. The nonreciprocal phase shift in the magneto-optic waveguides is measured by using a new improved measurement method. These waveguides exhibit the largest nonreciprocal phase shift ever reported of 21.1 rad/cm @=1.55 pm). 4877

A new waveguide isolator which has a simple structure is proposed and experimentally demonstrated. The isolator operates on the basis of nonreciprocal guided-radiation mode conversion in a channel magneto-optic waveguide. The isolator was realized using a single-mode rib channel waveguide in Ce-substituted yttrium iron garnet which has a very large Faraday rotation. 13.3 dB isolation was obtained at a wavelength near 1.55 μm.

Ce-substituted yttrium iron garnet films are epitaxially grown in situ on (111)-oriented substrates of (Gd, Ca, Mg)3(Ga, Zr)5O12 garnet by conventional rf diode sputtering for application to magneto-optic waveguide devices in optical communication systems. Pure argon or argon containing a small amount of oxygen is used as the sputter gas. After sputtering, the films are annealed in a nitrogen atmosphere. By optimizing this process, film propagation loss can be reduced while maintaining a large Faraday rotation. A propagation loss of 13 dB/cm and a Faraday rotation of -3900°/ cm have been obtained at a wavelength of 1.55 µ m.

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We investigated the structure and lattice deformation of CeY2Fe5-δO12-Z (Ce1·YIG) film prepared by RF sputtering. We found that the lattice constant parallel to the film plane a // is equal to the lattice constant of the substrate a s. This shows that this Ce1·YIG film belongs to Region I in the Besser model. Some Ce1·YIG films become a double-layer structure as the lattice constant mismatch || Δa|| increases. This change in the film structure caused by || Δa|| is very different from that of LPE film. In a Faraday rotation θF spectrum of single-layer films deposited on GCGMZG and GGG substrates, the θF dispersion around 800 nm is shifted to the longer wavelength side. We consider this θF shift around 800 nm to be induced by the difference in the film deformation.