Bandpass response of collinear beam acousto-optic tunable filters

This paper presents theoretical and experimental results of the collinear beam acousto-optic tunable filter (CBAOTF) for wavelength division multiplexing (WDM) applications. The bandpass response of a TeO/sub 2/ CBAOTF is calculated taking into account the effect of optical beam divergence. Significant improvement of the bandpass response is obtainable by properly apodizing the acoustic excitation. The experimental results of a polarization independent CBAOTF measured at 1550 nm include 1.3 nm bandwidth, 95 percent diffraction efficiency at a drive power of less than 100 mW. The bandpass falls off below 27 dB at 3 nm away from the center wavelength.