Highly coherent supercontinuum generation in CS2-infiltrated single-core optical fiber

As is generally known, the broadband near-infrared supercontinuum (SC) is significant for applications such as pump-probe spectroscopy, nonlinear spectroscopy, frequency combs and nonlinear optical parametric amplification. We present the first detailed demonstration of approximate near-infrared, octave-spanning SC generation in an all-normal dispersion CS2 single-hole liquid core optical fiber (LCOF). By solving the generalized nonlinear Schrodinger equation, the SC can be calculated at different parameters. The influence of important parameters-including but not limited to the fiber core diameter, pump wavelength, pump power and pulse width-on the supercontinuum generation (SCG) of a CS2-infiltrated LCOF can be analyzed for the optimization of near-infrared SCG. The results show that at low pump power (such as P-0 = 4 kW), the SC generated by using two pump wavelengths (1.55 mu m and 1.95 mu m) has spectral flatness, good coherence and is octave-spanning. However, the bandwidth is severely affected by the large pulse duration T-0, and the coherence is seriously influenced by the pulse duration T-0 > 1200 fs at the pump wavelength of 1.55 mu m. The effect of pulse duration on the first-order coherence is greater at short pump wavelengths (1.55 mu m) than long wavelengths (1.95 mu m). Under high power conditions (such as P-0 = 20 kW), the coherence of the SC generated remains good at the two-pump wavelength. This study explores an optimized scheme for obtaining a broadband SC with high coherence and fine spectral flatness suitable for specific applications.