Development of Electro-Optic Phase Modulator for 94 GHz Imaging System

This paper presents the latest improvements in design and fabrication of ridged LiNbO3 optical phase modulators operating in the W-band for millimeter-wave imaging applications at 94 GHz. It describes the design conditions for effective index matching between optical carrier at 1550 nm and millimeter-wave signal, as well as impedance matching and propagation losses reduction. The impacts of different geometric parameters on the device performance are discussed. In addition, the paper reports the diverse material processing techniques for device fabrication. Characterization of the fabricated devices shows conversion efficiency as high as 1.045 W-1 at 94 GHz with a 7 V dc half-wave voltage and a 3.7 dB optical insertion loss.