Generation of tightly compressed solitons with a tunable frequency shift in Raman-free fibers

TL;DR

This paper proposes a method to generate tightly compressed, tunable-frequency solitons in Raman-free photonic crystal fibers, achieving superior compression and stability by optimizing third-order dispersion effects.

Contribution

It introduces a novel approach for soliton compression in Raman-free fibers, identifying an optimal third-order dispersion value dependent only on the initial soliton order.

Findings

Optimal third-order dispersion enhances soliton compression

Compression degree exceeds traditional analytical predictions

Fundamental solitons maintain frequency post-separation

Abstract

Optimization of the compression of input N-solitons into robust ultra-narrow fundamental solitons, with a tunable up- or downshifted frequency, is proposed in photonic crystal fibers (PCF) free of the Raman effect. Due to the absence of the Raman self-frequency shift, these fundamental solitons continue propagation maintaining the acquired frequency, once separated from the input N-soliton's temporal slot. A universal optimal value of the relative strength of the third-order-dispersion (TOD) is found, providing the strongest compression of the fundamental soliton, is found. It depends only the order of the injected N-soliton. The largest compression degree significantly exceeds the analytical prediction supplied by the Satsuma-Yajima (SY) formula. The mechanism behind this effect, which remains valid in the presence of the self-steepening, is explained.