Coherent optical communications using coherence-cloned Kerr soliton microcombs

TL;DR

This paper demonstrates the re-generation of Kerr soliton microcombs that clone the frequency and phase coherence of transmitted signals, enabling simplified, high-capacity coherent optical communication over long distances.

Contribution

It introduces a method to faithfully clone Kerr soliton microcombs' coherence at the receiver, enhancing coherent communication efficiency and simplifying digital signal processing.

Findings

Successful microcomb re-generation with preserved coherence over 50 km

Terabit data interconnect achieved without traditional frequency offset estimation

Simplified carrier phase estimation through slowed-down and joint phase processing

Abstract

Dissipative Kerr soliton microcomb has been recognized as a promising on-chip multi-wavelength laser source for fiber optical communications, as its comb lines possess frequency and phase stability far beyond independent lasers. In the scenarios of coherent optical transmission and interconnect, a highly beneficial but rarely explored target is to re-generate a Kerr soliton microcomb at the receiver side as local oscillators that conserve the frequency and phase property of the incoming data carriers, so that to enable coherent detection with minimized optical and electrical compensations. Here, by using the techniques of pump laser conveying and two-point locking, we implement re-generation of a Kerr soliton microcomb that faithfully clones the frequency and phase coherence of another microcomb sent from 50 km away. Moreover, leveraging the coherence-cloned soliton microcombs as carriers and local oscillators, we demonstrate terabit coherent data interconnect, wherein traditional digital processes for frequency offset estimation is totally dispensed with, and carrier phase estimation is substantially simplified via slowed-down phase estimation rate per channel and joint phase estimation among multiple channels. Our work reveals that, in addition to providing a multitude of laser tones, regulating the frequency and phase of Kerr soliton microcombs among transmitters and receivers can significantly improve coherent communication in terms of performance, power consumption, and simplicity.