arXiv subjects

Karolina Stefańska

Publications and source records attributed to Karolina Stefańska.

3 recordsLinked to original sources

arXiv2024

High-gain far-detuned nonlinear frequency conversion in optical fibers: intramodal vs. intermodal processes

We present theoretical and experimental evidence of high-gain far-detuned nonlinear frequency conversion, extending towards both the visible and the mid-infrared, in a few-mode graded-index silica fiber pumped at 1.064 $μ$m, and more specifically achieving gains of hundreds of dB per meter below 0.65 $μ$m and beyond 3.5 $μ$m. Our findings highlight the potential of graded-index fibers in terms of strong modal confinement over an ultrabroad spectral range for enabling high-gain wavelength conversion. Such advancements require an accurate interpretation of intramodal and intermodal four-wave mixing processes.

physics.optics↗

arXiv2022

Experimental observation of spontaneous emission of space-time wavepacket in a multimode optical fiber

We provide a complete analysis, from theory to experiment, of the spontaneous emergence of a discretized conical wave of X-type (i.e., a localized 2D+1 space-time wavepacket) when an intense ultrashort pulse nonlinearly propagates in a multimode fiber. In particular, we reveal that this spatiotemporal phenomenon corresponds to broadband intermodal dispersive wave emission from an unsteady localized wave structure formed during nonlinear propagation. Theoretical phase-matching predictions are experimentally and numerically confirmed in a commercially-available step-index multimode fiber. Our results provide a general understanding of phase-matched radiations emitted by nonlinear waves in multidimensional dispersive optical system.

physics.optics↗

arXiv2022

Soliton trapping and orthogonal Raman scattering in a birefringent microstructured fiber

We report on trapped pulse generation in birefringent microstructured optical fiber. Linearly polarized fs pulses are injected into the microstructured fiber in anomalous dispersion regime. We observed experimentally that soliton pulse polarized along the fast fiber axis partially transfers its energy to the orthogonal polarization. The generated pulse is amplified through the orthogonal Raman gain. The two polarization components are located at group-velocity matched wavelengths. The experimental works are supported with numerical simulations. The obtained results are important for the light sources using self-frequency shifted solitons in applications demanding high polarization purity.

physics.optics↗