Supercontinuum generation in photonic crystal fibers infiltrated with nitrobenzene

A photonic crystal fiber made of fused silica glass and infiltrated with nitrobenzene (C6H5NO2) was proposed as a new nonlinear medium for supercontinuum generation (SG). The guiding properties of the fiber structure were studied numerically, including estimation of the effective refractive index, attenuation, and dispersion of the fundamental mode. Based on the obtained results, three optimized structures were selected and tested numerically for SG. With numerical simulations of nonlinear propagation, we demonstrated the feasibility of spectrally broad and coherent SG in the proposed structures. For the first we obtained a supercontinuum (SC) in the range of 0.8-1.8 µm, for the second in the range of 0.8-2.1 µm, and for the third 1.3-2.3 µm. The pulse energy was in the range of 0.06-0.5 nJ while the pulse duration was 90 fs or 120 fs. For all structures an SC was formed in the first centimeter of the light propagation and conveniently allowed to assume short segments of the fibers. The proposed fibers are good candidates for all-fiber SC sources constituting an attractive alternative to glass-core fibers, since the nonlinearity of nitrobenzene is significantly higher than that of silica. The proposed solution may lead to new low-cost all-fiber optical systems for SG.