Multilayer films composed of periodic magneto-optical and dielectric layers for use as Faraday rotators

Since multilayer films composed of periodic magneto-optical (M) and dielectric (G) layers have an enhanced Faraday effect, we investigated the possibility of using them as Faraday rotators for optical isolators. Under a constant magnetic field, the rotation can be adjusted precisely by adding an extra magneto-optical layer in which the rotation is proportional to the thickness. When the magnetic field is assumed to be variable, the rotation can be adjusted through the change in the magnetic induced permittivity of the magneto-optical layer. Since our investigation revealed that the rotation can be adjusted precisely, it is suggested that the use of multiple films with a rotation of half or one-third of 45 degrees would make it possible to assemble low loss isolators. (C) 1999 Elsevier Science B.V. All rights reserved.