Abstract

Parallel read/write systems are attractive in optical memory applications, and integrated-optic implementation of pickup devices would result in compact/light heads with high producibility and application flexibility. By modifying an integrated-optic disc pickup device (IODPU),¹ we propose and demonstrate a combination of a linearly focusing grating coupler (LFGC)^2,3 and a coplanar Bragg grating lens⁴ (beam splitting/imaging grating; BSIG) for integrated-optic parallel pickup. Figure 1 illustrates a schematic view of the integrated-optic device. A guided wave diverging from a butt-coupled laser diode (LD) is diffracted by the LFGC to be a focusing beam of cylindrical wave front in the air. The linearly focused beam is reflected by a recorded medium, so the wave front is no longer cylindrical but modulated by the multiple digital data on the focus line. The reflected wave is back-coupled by the same LFGC into the waveguide and imaged by the BSIG onto a photodiode array.

© 1990 Optical Society of America