OSNR limitations of chip-based optical frequency comb sources for WDM coherent communications

TL;DR

This paper examines the OSNR limitations of chip-based optical frequency comb sources in WDM coherent communications, analyzing how comb line power and noise affect system performance and capacity.

Contribution

It provides a detailed analysis of OSNR constraints and performance regimes for chip-based comb sources in WDM systems, including the impact on link reach and modulation choices.

Findings

Identifies two operational regimes based on source and link limitations.

Analyzes the influence of comb line power and noise ratio on system performance.

Evaluates the maximum channel capacity achievable with soliton Kerr frequency combs.

Abstract

Optical frequency combs have the potential to become key building blocks of optical communication subsystems. The strictly equidistant, narrow-band spectral lines of a frequency comb can serve both as carriers for massively parallel data transmission and as local oscillator for coherent reception. Recent experiments have demonstrated the viability of various chip-based comb generator concepts for communication applications, offering transmission capacities of tens of Tbit/s. Here, we investigate the influence of the comb line power and of the carrier-to-noise power ratio on the performance of a frequency comb in a WDM system. We distinguish two regimes of operation depending on whether the comb source or the transmission link limits the performance of the system, i.e., defines the link reach, restricts the choice of modulation format and sets the maximum symbol rate. Finally, we investigate the achievable OSNR and channel capacity when using the tones of a soliton Kerr frequency comb as multi-wavelength carriers for WDM systems.