Observation of Correlation between Route to Formation, Coherence, Noise, and Communication Performance of Kerr Combs

TL;DR

This study investigates how the formation process of Kerr microresonator combs affects their coherence, noise, and optical communication performance, revealing a direct correlation between the comb generation route and its quality.

Contribution

It is the first to simultaneously analyze the relationship between comb formation pathways, coherence, noise, and communication performance in Kerr combs.

Findings

Single FSR combs show high coherence and low noise.

Multi-FSR initial combs exhibit degraded coherence and performance.

Formation route impacts comb quality and communication efficacy.

Abstract

Microresonator optical frequency combs based on cascaded four-wave mixing are potentially attractive as a multi-wavelength source for on-chip optical communications. In this paper we compare time domain coherence, radio-frequency (RF) intensity noise, and individual line optical communications performance for combs generated from two different silicon nitride microresonators. The comb generated by one microresonator forms directly with lines spaced by a single free spectral range (FSR) and exhibits high coherence, low noise, and excellent 10 Gbit/s optical communications results. The comb generated by the second microresonator forms initially with multiple FSR line spacing, with additional lines later filling to reach single FSR spacing. This comb exhibits degraded coherence, increased intensity noise, and severely degraded communications performance. This study is to our knowledge the first to simultaneously investigate and observe a correlation between the route to comb formation, the coherence, noise, and optical communications performance of a Kerr comb.