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.

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In this paper, we propose three solid-core photonic crystal fibers based on silica, with hexagonal, circular and square lattices as a cladding, composed of 8 rings of air-holes surrounding the core, infiltrated with ethanol. Using a commercial software we simulated the light propagation in these structures. The size of the air-holes was from 1 µm to 4 µm. We have shown that the fibers with the hexagonal lattices are optimal for supercontinuum generation since their dispersion characteristics are flat and the smallest.

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.

Octave spanning all-normal dispersion supercontinuum generation (SCG) was experimentally demonstrated in a solid, suspended-core fiber (SCF) infiltrated with water. Replacement of air with water in the cladding air-holes leads to a dramatic modification of the dispersion profile of the fiber, significantly flattening the characteristic over the visible and much of the near-infrared wavelength range at normal values. In such a fiber infiltrated with water, all-normal dispersion supercontinuum was generated with the spectral coverage from 435 nm to 1330 nm using femtosecond pumping with the output peak power of 150 kW and 800 nm central wavelength. The SCF without water infiltration – air in the cladding region – had a zero-dispersion wavelength at 760 nm and enabled the generation of the anomalous dispersion dynamics-based SCG in the wavelength range from 450 nm to 1250 nm. We also numerically calculated the coherence of simulated supercontinuum pulses with one-photon-per-mode noise seeds and point out that the all-normal dispersion SCG in suspended-core fiber infiltrated with water has the potential for high temporal coherence, while the fiber without water infiltration shows gradual decoherence of generated supercontinuum pulses with increasing pump power, over similar peak power range.

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We present a theoretical study of the kinetic equation for acoustic phonons in semiconductor quantum well with parabolic potential well under intense laser field. Using this method, we find the expression for the phonon rate coefficient for the general case, the condition of the acoustic phonon rate and the influence of the parameters of laser on this rate coefficient. We numerically calculate the rate of acoustic phonon excitation by the absorption of laser field energy at different temperature.