Service Communautaire d'Information sur la Recherche et le Développement - CORDIS

Characterization of optical and magneto-optic parameters of CoFe alloys at 1300nm wavelength

In the isolator configuration studied within the ISOLASER project, the non-reciprocal - isolating - effect is caused by a magnetized ferromagnetic metal film sputtered close the guiding core of an InP-based waveguide. The source of the non-reciprocal effect is the transverse magneto-optic Kerr effect in this metal film, present when transversely magnetizing this film - perpendicular to the light propagation direction and parallel to the metal-semiconductor interface. At infrared wavelengths however, very little is reported in literature on the magneto-optic properties of ferromagnetic materials.

Therefore, in order to optimise the choice of metal and, possibly even more important, to enable proper design of the isolator layer structure, these magneto-optic properties (i.e. the non-diagonal elements of the permittivity tensor) needed to be extracted. Furthermore, the complex refractive index of the metal film has also a large influence on the performance of the isolator, hence exact knowledge of this parameter is indispensable.

With the experimental set-up developed for this task (see project result no.35323), the optical and magneto-optic parameters of three CoFe alloys have been determined, providing clear input for the design of the optical isolator demonstrator. The three materials are Co90Fe10, Co50Fe50 and Fe. Of these compounds, the equiatomic Co50Fe50 clearly provides the best combination of optical and magneto-optical properties.

Reported by

Centre National de la Recherche Scientifique / Universite Paris-Sud
Institut dęElectronque Fondamentale, bâtiment 220, Université Paris-Sud
91405 Orsay cedex