In-phase and anti-phase synchronization in a laser frequency comb

TL;DR

This paper demonstrates the experimental generation of in-phase and anti-phase synchronization states in a quantum dot laser frequency comb, controlled by damping losses, linking laser behavior to classical coupled oscillator phenomena.

Contribution

It introduces a method to switch between two distinct synchronization states in a laser frequency comb by adjusting damping, connecting laser dynamics to classical synchronization and pattern formation.

Findings

Both in-phase and splay states can be generated in the same device.

Synchronization states are controlled by varying damping losses.

The study links laser frequency combs to classical coupled oscillator systems.

Abstract

Coupled clocks are a classic example of a synchronization system leading to periodic collective oscillations. This phenomenon already attracted the attention of Christian Huygens back in 1665,who described it as a kind of "sympathy" among oscillators. In this work we describe the formation of two types of laser frequency combs as a system of oscillators coupled through the beating of the lasing modes. We experimentally show two completely different types of synchronizations in a quantum dot laser { in-phase and splay states. Both states can be generated in the same device, just by varying the damping losses of the system. This effectively modifes the coupling among the oscillators. The temporal output of the laser is characterized using both linear and quadratic autocorrelation techniques. Our results show that both pulses and frequency-modulated states can be generated on demand. These findings allow to connect laser frequency combs produced by amplitude-modulated and frequency-modulated lasers, and link these to pattern formation in coupled systems such as Josephson-junction arrays.