Super-efficient temporal solitons in mutually coupled optical cavities

TL;DR

This paper introduces a novel approach using mutually coupled optical cavities to generate Kerr solitons, significantly enhancing energy conversion efficiency for practical broadband frequency comb applications.

Contribution

It proposes and demonstrates a new method of using coupled cavities to overcome efficiency limitations in Kerr soliton generation, inspired by impedance matching principles.

Findings

Nearly tenfold increase in energy conversion efficiency.

Successful demonstration with macro optical fiber ring cavities.

Potential for ultra-high efficiency soliton microcombs.

Abstract

A coherently driven Kerr optical cavity is able to convert a continuous-wave laser to a sequence of ultrashort soliton pulses, enabling the generation of broadband and mode-locked frequency combs. Kerr cavity solitons are balanced through an energy exchange with the driving pump field. Improving the energy conversion efficiency from the pump to the soliton is of great significance for practical applications, but remains an outstanding challenge due to a limited temporal overlap between the soliton and the pump. Here, we report the discovery of temporal Kerr solitons in mutually coupled cavities instead of a traditional single cavity. We propose a strategy for breaking the limitation of pump-to-soliton energy conversion, and connect the underlying mechanism to impedance matching in radiofrequency electronic circuits. With macro optical fiber ring cavities which share the same physical model as miniature optical microresonators, we demonstrate nearly one-order improvement of the efficiency. The results pave the way towards super-efficient soliton microcombs based on optical microresonators with ultra-high quality factors.