Microresonator Kerr frequency combs with high conversion efficiency

TL;DR

This paper demonstrates a significant increase in conversion efficiency for microresonator Kerr frequency combs, achieving around 30%, which enhances their potential for practical optical communication applications.

Contribution

The study reports the first experimental realization of ~30% conversion efficiency in phase-locked microcombs using broadband dark-pulse states, supported by a general efficiency analysis.

Findings

Achieved ~30% conversion efficiency in microcombs.

High-efficiency combs suitable for optical communications.

Identified key factors influencing efficiency such as coupling and duty cycle.

Abstract

Microresonator-based Kerr frequency comb (microcomb) generation can potentially revolutionize a variety of applications ranging from telecommunications to optical frequency synthesis. However, phase-locked microcombs have generally had low conversion efficiency limited to a few percent. Here we report experimental results that achieve ~30% conversion efficiency (~200 mW on-chip comb power excluding the pump) in the fiber telecommunication band with broadband mode-locked dark-pulse combs. We present a general analysis on the efficiency which is applicable to any phase-locked microcomb state. The effective coupling condition for the pump as well as the duty cycle of localized time-domain structures play a key role in determining the conversion efficiency. Our observation of high efficiency comb states is relevant for applications such as optical communications which require high power per comb line.