Abstract

Integrated-optic disk heads for magnetooptic systems provide the potential for increased tracking and focusing performance due to their lightness and multicomponent integration ability. A fully functional head would ideally include laser, polarization detection, fine tracking, and fine focusing integration into a single simple device. We propose a new integrated design, motivated by the Ura device,¹ which performs rapid tracking via electrooptic (EO) beam shaping. A highly EO planar waveguide is used to guide a wavefront to a grating coupler, which then couples the light normal to the guide and onto the disk. Lateral tracking at the disk plane can then be achieved by inducing beam shaping in the guide via the linear EO effect. Appropriate electrode geometries to induce the necessary index variations are described. The optical performance is evaluated using spot diagrams at the disk plan via ray-tracing through the device. First-order results indicate near diffraction-limited performance for lateral deflections over a 30-μm range. Extensions to perform electrooptically induced fine focusing over a 20-μm range are also discussed.

© 1991 Optical Society of America