Ultra-narrow linewidth self-adaptive photonic oscillator : principle and realization

TL;DR

This paper introduces a novel self-adaptive photonic oscillator that achieves ultra-narrow linewidth and high spectral purity without stabilization electronics, suitable for precise wavelength applications in physics and metrology.

Contribution

It presents a new principle for a self-adaptive optical oscillator using a long resonator and semiconductor laser, achieving high spectral purity without servo locking.

Findings

Lorentzian linewidth of 40 mHz achieved

Frequency drift within 10 MHz over hours

Applicable to any wavelength with laser diodes

Abstract

Highly coherent optical sources are a key element in several fields of physics, in particular in time frequency metrology. Over the past decennia, there has been particular efforts in developing such sources to the expense of sophisticated laser systems and relatively smart electronics. We propose here a new general principle of a self-adaptive oscillator where the intricate operation of a 100-m-long active optical resonator and a standard semiconductor laser offers a very high spectral purity and can be tailored to any wavelength. Single frequency operation of this self-adaptive photonic oscillator is achieved without any servo locking or stabilization electronics. Free running operation leads to a Lorentzian linewidth of 40 mHz. The long-term drift of the optical frequency in the free running regime is within 10 MHz over hours. This principle applies to any wavelength attainable by laser diodes which opens tremendous opportunities in particular in applications where atomic or molecular transitions require precise wavelengths.