Supercontinuum Generation In Liquid-Filled PCF

Since 1970,Alfano and Shapiro firstly observed the supercontinuum generation (SCG), which has attracted wide attention.High brightness, wide width, and good coherence are the characteristics of SC, which has been found numerous applications in diverse fields. The endless single-mode propagation, enhanced modal confinement, and flexibly adjustable group velocity dispersion and nonlinearity characteristics of photonic crystal fiber make it excellent medium for SCG. In recent years, the core of PCF filled with various liquids including carbon disulfide (CS2), water, carbon tetrachloride (CCL4), and benzene have aroused widespread concern. These liquids not only have a high nonlinear coefficient, but also have good transparency in the infrared region. The nonlinear coefficient of CS2 is very high, and the transparency in the infrared region is very well, and more importantly,there is a distinct nonlinear——slow nonlinearity in CS2. In this paper, the core of the PCF is filled with CS2 to study the SCG.The main work of this paper is as follows:1 The structure of the photonic crystal fiber is designed2 The influence of the slow nonlinearity on the spectrum and coherence of the supercontinuum is simulated. It is proved that the slow nonlinearity really will enhance the coherence of the supercontinuum and affect the dynamics of the soliton. Moreover, the slow nonlinearity can prolong the splitting length of the soliton.3 The influence of temperature, pump pulse width, peak power,fiber length, self-shake and nonlinear dispersion effect on the supercontinuum and its coherence were studied under the effect of slow nonlinearity.4 Considering all these factors, highly coherent and octave spanning supercontinuum is generated.