Characterization and Correction of Homodyne Systems Enabling Single-Carrier 40 Gb/s in E-Band

Linear distortions in homodyne systems are caused by variations in amplitude gain, time delay, and phase between the in-phase and quadrature components of an input signal. In this paper, we offer a novel technique for correcting these imbalances at a system level. We introduce a frequency-dependent characterization and correction procedure that supports high-frequency and wideband modulation signals at arbitrary resolution bandwidths. We demonstrate the application of our method by predistorting modulated waveforms transmitted through a 4-millimeter waveguide at E-band frequencies. Our results show that the received signals have a dynamic range of at least 40 dB, a large improvement over historical correction techniques. We assess our technique on 256-QAM constellations at 5 GBd (40 Gb/s) and measure 3.2% error vector magnitude, where comparable historical methods require various modifications in order to compare.