INTEGRATED ACOUSTOOPTIC TUNABLE FILTERS USING WEIGHTED COUPLING

A detailed theory and experimental results are presented on weighted-c oupling integrated acoustooptic tunable filters (IAOTF). A low-sidelob e-level single-stage IAOTF in which the weighted coupling was facilita ted by focused surface acoustic waves along an interaction length of 6 .0 mm has been realized on a Y-X LiNbO3 substrate, 8 mm in length. The measured performances of this weighted-coupling IAOTF at the optical center wavelength of 1.31 mum include a peak mode conversion at the ac oustic center frequency of 214.6 MHz, a wavelength tuning range of 110 nm, a -3 dB optical bandwidth of 4.1 nm, and a switching rise time of 0.965 mus. Sidelobe levels below -21.4 dB have been accomplished at t he mode-conversion efficiency of 15 percent and an RF drive power of 1 60 mW.