Coherent terabit communications with microresonator Kerr frequency combs

TL;DR

This paper demonstrates that Kerr frequency combs generated in microcavities can be stabilized and used for high-speed, multi-terabit coherent optical data transmission, paving the way for chip-scale terabit transceivers.

Contribution

The study shows for the first time that low phase-noise Kerr combs can support advanced modulation formats for multi-terabit coherent communications.

Findings

Encoded 392 Gbit/s data using Kerr combs with QPSK and 16QAM.

Achieved 1.44 Tbit/s transmission over 300 km.

Demonstrated stabilization of Kerr combs for high-capacity data transfer.

Abstract

Optical frequency combs enable coherent data transmission on hundreds of wavelength channels and have the potential to revolutionize terabit communications. Generation of Kerr combs in nonlinear integrated microcavities represents a particularly promising option enabling line spacings of tens of GHz, compliant with wavelength-division multiplexing (WDM) grids. However, Kerr combs may exhibit strong phase noise and multiplet spectral lines, and this has made high-speed data transmission impossible up to now. Recent work has shown that systematic adjustment of pump conditions enables low phase-noise Kerr combs with singlet spectral lines. Here we demonstrate that Kerr combs are suited for coherent data transmission with advanced modulation formats that pose stringent requirements on the spectral purity of the optical source. In a first experiment, we encode a data stream of 392 Gbit/s on subsequent lines of a Kerr comb using quadrature phase shift keying (QPSK) and 16-state quadrature amplitude modulation (16QAM). A second experiment shows feedback-stabilization of a Kerr comb and transmission of a 1.44 Tbit/s data stream over a distance of up to 300 km. The results demonstrate that Kerr combs can meet the highly demanding requirements of multi-terabit/s coherent communications and thus offer a solution towards chip-scale terabit/s transceivers.