Electro-optically derived millimeter-wave sources with phase and amplitude control

Abstract

Integrated circuits are building blocks in millimeter-wave handsets and base stations, requiring nonlinear characterization to optimize performance and energy efficiency. Today's sources use digital-to-analog converters to synthesize arbitrary electrical waveforms for nonlinear characterization, but this approach demands even faster integrated circuits to increase the bandwidth to millimeter-waves. Optically derived sources are a potential path to generate precise millimeter-waves and arbitrary waveforms using additive frequency synthesis. In this work, we demonstrate optically derived millimeter-waves up to 99.2 GHz with phase and amplitude control that could be locked to an optical reference. Our approach uses a 1550 nm electro-optic frequency comb with a terahertz of bandwidth. A programmable spectral filter selects two wavelengths from the optical comb, illuminating a modified uni-traveling carrier photodiode on a coplanar waveguide. We then tune the phase and amplitude by varying the optical phase and amplitude in the programmable spectral filter. The result of our work is electro-optically derived millimeter-waves at (24.8, 49.6, 74.4, and 99.2) GHz with phase and amplitude control, enabling arbitrary repetitive waveform generation.