Terabit/s communications using chip-scale frequency comb sources

High-speed optical interconnects rely on advanced wavelength-division multiplexing (WDM) schemes. However, while photonic-electronic interfaces can be efficiently realized on silicon-on-insulator chips, dense integration of the necessary light sources still represents a major challenge. Chip-scale frequency comb sources present an attractive alternative for providing a multitude of optical carriers for WDM transmission. In this paper, we give an overview of our recent progress towards terabit communications with chip-scale frequency comb sources. In a first set of experiments, we demonstrate frequency comb generation based on silicon-organic hybrid (SOH) electro-optic modulators, enabling line rates up to 1.152 Tbit/s. In a second set of experiments, we use injection locking of a gain-switched laser diode to generate frequency combs. This approach leads to line rates of more than 2 Tbit/s. A third set of experiments is finally dedicated to using Kerr nonlinearities in integrated nonlinear microcavities for frequency comb generation. We demonstrate coherent communication using Kerr frequency comb sources, thereby achieving line rates up to 1.44 Tbit/s. Our experiments show that frequency comb generation in chip-scale devices represents a viable approach to terabit communications.