ABSTRACT
In this paper, the authors demonstrate a simple technique for the fabrication of circular gratings using direct Focused Ion Beam (FIB) damaging of GaAs and selective etching. This simple technique allows not only the fabrication of high quality circular gratings, but also good control over the tooth height and pitch which is essential for good optical performance of the grating. Since the optical response of gratings is strongly related to the depth of the gratings, it is important to fabricate deeper gratings. The optical characteristics of the grating were then evaluated with a 1.06 µm YAG laser. The reflected light from the grating was observed with an I.R. camera. The authors investigate the variation of grating profile as a function of the exposure dose. The optical characteristics of second order circular gratings on a GaAs/AlGaAs waveguide show good performance suitable for surface-emitting lasers.
