Thermodynamic control of soliton dynamics in liquid-core fibers

Abstract

Liquid-core fibers offer local external control over pulse dispersion due to their strong thermodynamic response, offering a new degree of freedom in accurate soliton steering for reconfigurable nonlinear light generation. Here, we show how to accurately control soliton dynamics and supercontinuum generation in carbon disulfide/silica fibers by temperature and pressure tuning, monitored via the spectral location and the onset energy of non-solitonic radiation. Simulations and phase-matching calculations based on an extended thermodynamic dispersion model of carbon disulfide confirm the experimental results, which allows us to demonstrate the potential of temperature detuning of liquid-core fibers for octave spanning recompressible supercontinuum generation in the near-infrared.

Resonance‐Induced Dispersion Tuning for Tailoring Nonsolitonic Radiation via Nanofilms in Exposed Core Fibers

“…The SCG tuning concept represents a tuning approach that can principally be applied to any waveguide structure with a free standing core, for instance including planar ridge waveguides [ 45 ] or fiber optical tapers. [ 26 ] The achieved DW tuning bandwidth of 298 nm exceeds those of other post‐fabrication tuning scheme for a fixed pump wavelength in the near infrared employing changing either temperature or pressure (140 [ 19 ] and 60 nm, [ 22 ] respectively). To improve bandwidth and uniformity of the generated spectra further coupling efficiencies have to be increased or the laser needs to be replaced in order to obtain higher in‐fiber peak power and thus to excite higher order solitons and enable soliton fission.…”

Higher-order mode supercontinuum generation in dispersion-engineered liquid-core fibers

“…Hence, we might observe efficient ultrafast energy transfer to a perfectly phase-matched signal band in the normal dispersive domain, which is seeded by the DW generated earlier 53 – 55 , 58 , 59 . Single-mode simulations solving the nonlinear Schrödinger equation for increasing pulse energy 23 show a very similar spectral evolution with one major peak in each ND domain left and right of the pump, see supplementary information VI Fig. S7 .…”

“…In the present work, we demonstrate few-mode step-index liquid-core fibers (LCFs), with precisely adapted circular core diameters, as a novel platform to study nonlinear dynamics in HOMs. LCFs benefit from (1) distinct step-index refractive index profiles with index contrasts comparable to soft-glass fibers 22 , enabling straightforward mode modeling and large effective index differences between different modes, (2) the lack of mode perturbations through internal material stress, and (3) potential local control over the nonlinear dynamics via temperature 23 . Those benefits clearly distinguish the capabilities of LCFs from other nonlinear fibers, and allow to excite different types of HOMs (TE 0n , TM 0n , HE 1n , HE n1 , etc.)…”

Long-term stable supercontinuum generation and watt-level transmission in liquid-core optical fibers

“…These fibers feature liquids as core materials and host unique opportunities for dispersion design. Inorganic solvents have been the focus of recent research in LCFs due to their high nonlinear refractive indices [11][12][13], their potentially high transparency at MIR wavelengths [14], their capability for realtime dispersion tuning via extraordinary high thermo-optical coefficients [15], and their noninstantaneous nonlinear response [11][12][13]. First SCG experiments using LCFs were reported in [16][17][18], reaching wavelengths up to 2.4 µm while average output power levels were limited to <110 mW.…”