Slow‐Light‐Based Dispersion Compensation of High‐Speed Data on a Silicon Nitride Chip

Abstract

Transmission of optical data over fiber is subjected to signal degradation from dispersion impairments that worsen with increasing fiber lengths and higher data rates. Consequently, dispersion impairments significantly limit the data rates and reaches of transceivers used for data center communications. Herein, the design and experimental demonstration of a low loss, CMOS‐compatible on‐chip silicon nitride transmission grating device for dispersion compensation of high‐speed data are reported. The design, which involves inscribing a perturbation in the effective index profile of the grating, generates a considerable increase in the dispersion magnitude and enables up to 25 km of single‐mode fiber to be compensated for. Importantly, high‐speed measurements after dispersion compensation of a 20 km single‐mode fiber, using non‐return‐to‐zero data at rates up to 28.05 Gb s−1 show nine orders of magnitude reduction in BERs from 5  10−1 to 1  10−10, accompanied by significant improvements in the eye diagram. The underlying operating mechanism involves slow‐light effects that are designed to generate large dispersion while maintaining low losses. A pathway toward dispersion impairment‐free high‐speed data transmission over fiber using a compact device is demonstrated, which can be seamlessly integrated within transceiver chips, bringing the applicability of slow‐light devices firmly into the domain of commercial viability.