Analysis of electrical crosstalk in thin-film lithium niobate Mach-Zehnder modulator arrays

In order to meet the rapidly growing bandwidth requirements of high-performance computers and data centers, the number of parallel channels in short-range optical interconnect links is expected to increase several times, and crosstalk due to high integration density may reduce the transmission performance and ultimately limit the possible integration density. In this paper, the electrical crosstalk between parallel thin-film lithium niobate Mach-Zehnder modulators (MZMs) is systematically analyzed, and the noise reduction effects of traveling-wave MZMs with differential dual-drive electrodes, a virtual ground structure, and a fully matched terminating circuit are studied. The simulation results show that the far-end and near-end crosstalk coefficients between two adjacent MZMs are less than 1% and 0.5%, respectively. The near-end crosstalk voltage caused by the bonding wire is less than 15 mV, and the voltage ripples at the far end are eliminated. A high signal-to-noise ratio of 20.3 dB is realized, and therefore the effectiveness of the crosstalk suppression methods is verified.