All-normal dispersion supercontinuum (ANDi SC) generation in a lead-bismuth-gallate glass solid-core photonic crystal fiber (PCF) with cladding air-holes infiltrated with carbon tetrachloride (CCl₄) is experimentally investigated and numerically verified. The liquid infiltration results in additional degrees of freedom that are complimentary to conventional dispersion engineering techniques and that allow the design of soft-glass ANDi fibers with an exceptionally flat near-zero dispersion profile. The unique combination of high nonlinearity and low normal dispersion enables the generation of a coherent, low-noise SC covering 0.93–2.5 µm requiring only 12.5 kW of pump peak power delivered by a standard ultrafast erbium-fiber laser with 100 MHz pulse repetition rate (PRR). This is a much lower peak power level than has been previously required for the generation of ANDi SC with bandwidths exceeding one octave in silica- or soft-glass fibers. Our results show that liquid-composite fibers are a promising pathway for scaling the PRR of ANDi SC sources by making the concept accessible to pump lasers with hundreds of megahertz of gigahertz PRR that have limited peak power per pulse but are often required in applications such as high-speed nonlinear imaging, optical communications, or frequency metrology. Furthermore, due to the overlap of the SC with the major gain bands of many rare-earth fiber amplifiers, our source could serve as a coherent seed for low-noise ultrafast lasers operating in the short-wave infrared spectral region.

This study proposes a photonic crystal fiber (PCF) made of fused silica glass with the core infiltrated with 1,2-dibromoethane ( C 2 H 4 B r 2 ) as a new source of supercontinuum light pulses. Due to the modifications of the PCF’s structure geometry, a number of computer simulations investigating their optimized structures has been carried out. This aimed at achieving flat near-zero dispersion and zero dispersion wavelength matching of the pump wavelength for efficient spectral broadening. Based on the obtained results, the structural geometries of two C 2 H 4 B r 2 -core PCFs were optimized using numerical modeling for broadband supercontinuum (SC) generation. The first fiber structure with a lattice constant 1.5 µm and filling factor 0.4 has all-normal dispersion profile. The SC with a broadened spectral bandwidth from 0.64 to 1.70 µm is generated by pump pulses centered at a wavelength of 1.03 µm, 120 fs duration, and energy of 1.5 nJ. The second proposed structure—with lattice constant 1.5 µm and filling factor 0.65—has anomalous dispersion for wavelengths longer than 1.03 µm. We obtained high coherence of the SC pulses in the anomalous dispersion range over wavelengths of 0.7–2.4 µm with the same pump pulse as the first fiber and with input energy of 0.09 nJ. These fibers would be interesting candidates for all-fiber SC sources operating with low-energy pump lasers as cost-effective alternatives to glass core fibers.

We report an experimental study on transmission of orbital angular momentum mode in antiresonant fibers generated with a dedicated all-fiber optical vortex phase mask. The vortex generator can convert Gaussian beam into vortex beams with topological charge l = 1. Generated vortex beam is directly butt-coupled into the antiresonant fiber and propagates over distance of 150 cm. The stability and sensitivity of the transmitted vortex beam on the external perturbations including bending, axial stress, and twisting is investigated. We demonstrate distortion-free vortex propagation for the axial stress force below 0.677 N, a bend radius greater than 10 cm.

This work presents a polarization-maintaining (PM) highly nonlinear Ge ₂₀ As ₂₀ Se ₁₅ Te ₄₅ chalcogenide photonic crystal fiber (PCF) designed for broadband mid-infrared (MIR) supercontinuum (SC) generation. Through optimization of the PM-PCF’s geometrical parameters, the proposed fiber exhibits ultra-flat normal dispersion properties for the fundamental mode with the x -polarization component. In contrast, the y -polarization fundamental mode, the proposed PCF provides flat anomalous dispersion properties at a pump wavelength of 9.8 μ m. The effects of input energy and pulse width on the spectral profiles and coherence properties of the SC spectrum are investigated. The result is a highly coherent SC extending from 4.98 µ m to 15.08 µ m (a bandwidth of 10.1 µ m) and from 2.9 µ m to 25.2 µ m (a bandwidth of 22.45 µ m) in the MIR region when a pump pulse with a wavelength of 9.8 μ m is used for the designed fiber with the x -polarization and y -polarization factors, respectively. The proposed PM-PCF-based SC source shows potential as a candidate for nonlinear applications, including frequency metrology, optical sensing, and optical tomography.