Small core As2Se3-based photonic crystal fibers (PCFs) are accurately characterized for compact, high power, ultrabroadband, and coherent supercontinuum generation within few millimeters fiber length. Bandwidths of ~5.3？μm, 5？μm, and 3.2？μm were calculated for hole-to-hole spacings 3.5？μm, 4.5？μm, and 5.5？μm, respectively. The spectral broadening in the chalcogenide PCF is mainly caused by self-phase modulation and Raman-induced soliton self-frequency shift. The results show that small core As2Se3 PCFs are a promising candidate for mid-IR SCG up to ~8？μm. 1. Introduction Supercontinuum generation (SCG) brings into play the nonlinear effects of Kerr and Raman, in combination with dispersion profiles of optical fibers, to broaden the bandwidth of an optical signal [1, 2]. Silica fibers have been the main source of SCG to date [3]. However, the longest wavelength that can be generated in silica fibers is below 2.5？μm due to material losses. Thus, SCG beyond this wavelength requires fibers with longer infrared (IR) transmission windows, along with an appropriate choice of dispersion and nonlinearity [4, 5]. Midinfrared photonics is seeing an increasing number of applications across a variety of disciplines such as astronomy and spectroscopy [6]. Price et al. [7] have shown theoretically that it is possible to generate a mid-IR supercontinuum from 2 to 5？μm using a bismuth-glass photonic crystal fiber (PCF). Domachuk et al. [8] have experimentally generated a mid-IR supercontinuum with a spectral range of 0.8 to 4.9？μm using a tellurite PCF with the same structure. Shaw et al. have reported experimental work that demonstrates supercontinuum generation from 2.1 to 3.2？μm in an As2Se3-based chalcogenide PCF with one ring of air holes in a hexagonal structure [9]. Hu et al. presented results of optimization of the SC bandwidth in an As2Se3-based PCF [10]. Compared to tellurite glass, chalcogenide glasses have shown their greater interest because of their larger refractive index and higher nonlinear index, leading to a greater modal confinement and a higher nonlinearity [11, 12]. In a recent paper, we studied SCG in one specific As2Se3-based PCF structure having a hole diameter ？μm and a hole-to-hole spacing ？μm [13]. However, such a study remains incomplete because it does not answer the question how a specific set of values for various dispersion coefficients can affect the generated bandwidth of the SC. In this paper we identify specific dispersion profiles and correlate them with generated SC bandwidth. Our numerical simulations indicate that designed
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