Soliton self-frequency blue-shift in gas-filled hollow-core photonic crystal fibers

TL;DR

This paper theoretically demonstrates that in gas-filled hollow-core photonic crystal fibers, solitons can experience a continuous blue-shift due to photoionization, contrasting with the red-shift in solid fibers, and explores novel soliton interactions and transformations.

Contribution

It introduces the concept of soliton blue-shift caused by photoionization in hollow-core fibers and predicts new long-range soliton interactions and spectral transformations.

Findings

Photoionization causes soliton blue-shift in hollow-core fibers.

Unconventional long-range soliton interactions lead to clustering.

Spectral transformations occur with Raman-active gases.

Abstract

We show theoretically that the photoionization process in a hollow-core photonic crystal fiber filled with a Raman-inactive noble gas leads to a constant acceleration of solitons in the time domain with a continuous shift to higher frequencies, limited only by ionization loss. This phenomenon is opposite to the well-known Raman self-frequency red-shift of solitons in solid-core glass fibers. We also predict the existence of unconventional long-range non-local soliton interactions leading to spectral and temporal soliton clustering. Furthermore, if the core is filled with a Raman-active molecular gas, spectral transformations between red-shifted, blue-shifted and stabilized solitons can take place in the same fiber.