Abstract

A number of architectures for integrated optic (IO) space-division switching,¹ using guided-wave electro-optic (EO) switches² have been implemented in recent years. Unlike the guided-wave EO devices, guided-wave acoustooptic (AO) devices³ can facilitate a multiplicity of AO Bragg diffractions in the same interaction region of a planar waveguide by controlling the directivity of multiple input light beams, and the directivity and the carrier frequency of the surface acoustic waves (SAWs). Under such circumstances, proper design enables AO Bragg diffraction to take place between a designated pair of a light beam and a SAW without causing significant crosstalk to other similarly interacting pairs. In consummating the above idea, asymmetric⁴ and symmetric⁵ 4×4 nonblocking guided-wave AO space switches have been constructed recently. As shown in Fig. 1, the 8×8 AO space switch array to be reported here has been fabricated on a Y-cut LiNbO₃ substrate, 1.0×10.0×37.0mm³ in size, and consists of a titanium indiffused channel-planar-channel composite waveguide, a pair of titanium-indiffused proton- exchanged (TIPE)⁶ planar waveguide lenses, and a pair of four-element tilted SAW interdigital transducers (IDTs).⁷ Potentially, as the size of the switch array increases, these AO switch arrays incur considerably smaller increments in waveguide substrate size and number of on-chip switching elements as well as lower performance degradations such as differential crosstalk and differential insertion loss¹ than in the EO switch arrays.

© 1992 Optical Society of America