Abstract

Integrated acoustooptic tunable filters (AOTFs) have been shown to have potential applications in optical wavelength-division-multiplexed systems.¹ The single-stage integrated AOTFs reported previously² all use uniform coupling between the surface acoustic waves (SAWs) and guided-optical waves throughout the interaction length, resulting in best filter sidelobe levels of up to-9dB. It was recently suggested³ that the replacement of uniform-coupling with weighted-coupling would result in significant reduction of the sidelobe levels of the filter. In the weighted-coupling schemes, the coupling constant, κ, of the collinear AO interaction for mode conversion varies along the interaction length. Higher values of κ in the middle region of the interaction length with appropriate tapering of κ values in its end regions would result in significantly lower sidelobe levels.

© 1992 Optical Society of America