Measurements of Faraday effect in iron garnet optical waveguide at near infrared wavelengths

Abstract

The Faraday rotation constants in a magneto-optic channel waveguide whose magnetization aligns along the direction of propagation are measured by a novel method developed by the authors. The tested sample is a lanthanum and gallium substituted yttrium iron garnet optical channel waveguide prepared by the liquid phase epitaxial and the ion milling techniques. The proposed method is more practical than the previously reported one because of determination of the parameters with one time measurement. In the previous method we needed to know the phase constant difference between the orthogonally polarized waves to determine the Faraday coefficient. Using the presented technique we successfully measure the magneto-optic coefficients in the iron garnet waveguide at the near infrared wavelengths: 1.15, 1.3, and 1.55 μm. We confirm the validity of the proposed method by comparing with other methods: the previously reported method and the Faraday modulation method conventionally used for measuring the Faraday rotation. We also demonstrate the waveguide isolator operation.