Narrow linewidth lasing and soliton Kerr-microcombs with ordinary laser diodes

TL;DR

This paper demonstrates that ordinary multi-frequency laser diodes can be transformed into narrow-linewidth single-frequency sources and coherent soliton Kerr microcombs using self-injection locking with microresonators, enabling compact and efficient optical frequency combs.

Contribution

It introduces a method to generate narrow-linewidth lasers and soliton microcombs from standard laser diodes via self-injection locking, bypassing the need for specialized pump lasers.

Findings

Multi-frequency laser diodes can be converted into narrow-linewidth sources.

Self-injection locking enables stable single-frequency operation.

The approach allows for low-power, integrated soliton microcomb generation.

Abstract

Narrow linewidth lasers and optical frequency combs generated with mode-locked lasers revolutionized optical frequency metrology. The advent of soliton Kerr frequency combs in compact crystalline or integrated ring optical microresonators opens new horizons for applications. These combs, as was naturally assumed, however, require narrow-linewidth single-frequency pump lasers. We demonstrate that a regular multi-frequency Fabry-Perot laser diode self-injection locked to an optical whispering gallery mode (WGM) microresonator can be first efficiently transformed to a single-frequency ultra-narrow-linewidth source and then to coherent soliton comb oscillator with low power consumption and possibility of further integration.