Abstract

Magnetostatic waves-based guided-wave magnetooptic (MO) Bragg cells in yttrium iron garnet-gadolinium gallium garnet (YIG-GGG) waveguide possess the unique capabilities of electronically tunable carrier frequency beyond X-band microwave frequencies and GHz bandwidth, and are therefore inherently capable of direct RF signal processing at the carrier frequencies from 0.5 to 26.5 GHz[l]. Other capabilities include multiport light beam scanning and switching at a speed one- to three-order of magnitude higher than that of acoustooptic (AO) Bragg cells [2]. Obviously, it is desirable to incorporate lenses and lens arrays in the same YIG- GGG waveguide substrate to realize integrated MO Bragg cell modules. Negative-index change waveguide lenses which combine analog Fresnel and chirp gratings were fabricated recently in LiNbO₃, GaAs and YIG-GGG waveguide substrates using ion-milling technique [3]. It has been concluded that the thinner the waveguide, the smaller the required milled-depth in the gratings in order to produce desired index changes, and thus ensure high lens throughput.

© 1992 Optical Society of America