INTEGRATED ACOUSTOOPTIC HETERODYNING DEVICE MODULES IN LINBO3 SUBSTRATE

This paper reports the realization of integrated acousto-optic (AO) device modules that combine a wideband AO Bragg cell, an ion-milled Bragg diffraction grating, and a titanium-indiffused proton-exchanged waveguide lens in a Y-cut LiNbO3 substrate, 1 x 8 x 16 mm3 in size, to perform optical heterodyning, and their application to rf signal processing. These integrated AO heterodyne modules have demonstrated the capabilities for channelized detection of the amplitude, the frequency, and the phase of wideband rf signals and thus the capability to perform interferometric rf spectral analysis with significantly improved performances over the conventional AO Bragg cells. The single-unit (basic) modules have provided single-tone simultaneous and two-tone third-order spurious-free dynamic ranges of 51 and 40 dB, respectively, and a bandwidth of 205 MHz centered at 350 MHz at the optical wavelength of 0.6328-mu-m, the optical power of 1.0 mW, and the drive power of 50 mW/rf signal input. Furthermore the dual-unit modules that consist of a pair of identical basic heterodyne devices in the same LiNbO3 waveguide substrate, also 1 x 8 x 16 mm3 in size, have been constructed and used to measure the angle of arrival of the rf signals.