Integrated acoustooptic tunable filters using weighted coupling

A detailed theory and experimental results are presented on weighted-coupling integrated acoustooptic tunable filters (IAOTF). A low-sidelobe-level single-stage IAOTF in which the weighted coupling was facilitated by focused surface acoustic waves along an interaction length of 6.0 mm has been realized on a Y-X LiNbO/sub 3/ substrate, 8 mm in length. The measured performances of this weighted-coupling IAOTF at the optical center wavelength of 1.31 /spl mu/m include a peak mode conversion at the acoustic 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 /spl mu/s. Sidelobe levels below -21.4 dB have been accomplished at the mode-conversion efficiency of 15 percent and an RF drive power of 160 mW. >

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