Extremely elastic soliton crystals generated in a passively mode-locked tunable high-repetition-rate fiber laser

TL;DR

This paper reports the first direct observation of highly elastic, stable soliton crystals in a passively mode-locked fiber laser, capable of being stretched and compressed while maintaining their structure, with potential applications in high-repetition-rate optical systems.

Contribution

It introduces a novel type of elastic soliton crystal with controllable bond properties, demonstrated in a specially designed fiber laser, and explores their dynamic behaviors and stability.

Findings

Stable soliton crystals can be formed from dissipative solitons.

Soliton crystals can be stretched and compressed with a ratio over 30.

Pulse separation as low as 5 ps corresponds to 200 GHz repetition rate.

Abstract

We present the first direct observation of the bound state of multiple dissipative optical solitons in which bond length and bond strength can be individually controlled in a broad range in a regular manner. We have observed experimentally a new type of stable and extremely elastic soliton crystals that can be stretched and compressed many times conserving their structure by adjusting the bond properties in real time in a specially designed passively mode-locked fiber laser incorporating highly asymmetric tunable Mach-Zehnder interferometer. The temporal structure and dynamics of the generated soliton crystals have been studied using an asynchronous optical sampling system with picosecond resolution. We demonstrated that stable and robust soliton crystal can be formed by two types of primitive structures: single dissipative solitons, and(or) pairs of dissipative soliton and pulse with lower amplitude. Continuous stretching and compression of a soliton crystal with extraordinary high ratio of more than 30 has been demonstrated with a smallest recorded separation between pulses as low as 5 ps corresponding to an effective repetition frequency of 200 GHz. Collective pulse dynamics, including soliton crystal self-assembling, cracking and transformation of crystals comprising pulse pairs to the crystals of similar pulses has been observed experimentally.