Infrared 1000-nm-Supercontinuum by Means of Self-Frequency Shift of Raman Solitons Supported by Four-Wave Mixing

Infrared spectroscopy is deployed in various fields of science and technology such as organic and inorganic chemistry, monitoring of greenhouse gases, food industry, artwork conservation, and analysis of polymers and semiconductor microelectronics [1]. The supercontinuum generation based on self-frequency shift (SFS) of Raman solitons in various optical fibres is a technology to provide promising spectra for infrared spectroscopy applications. However, these spectra are restricted in range due to the limitations of Raman gain spectrum and optical absorption in silica fibres beyond the C band. Thus, they hardly spread over 300 nm if starting from around 1550 nm [2]. However, as I show here using numerical simulations of the Generalised Nonlinear Schrödinger Equation, if the SFS of Raman solitons is supported by the effect of four-wave mixing (FWM), the range of such supercontinuum can increase up to 1000 nm counteracting the limits of Raman gain and optical absorption.