Theoretical Research And Experiments Of Liquid-filled Hollow Core Fibers

The hollow core leaky optical fiber provides sufficient length for the interaction between light and filled-in matter.Therefore,it is convenient to provide an efficient platform to study many scientific problems in optics.Up to now,hollow core leaky optical fibers have been widely used in nonlinear optics and fiber sensing,and demonstrated frequency conversion,high order harmonic generation,supercontinuum generation,gas/liquid lasers,biomedical sensors,etc.This paper focuses on the study of transmission properties of liquid-filled hollow core fiber,and application in liquid lasing.First of all,the research background and significance of this topic are introduced.The research progresses of hollow fiber and liquid-filled hollow fiber at home and abroad are summarized.The light guiding mechanism of hollow leaky optical fiber and the full vector finite element method used for simulation are described.Secondly,by solving the wave equation,the analytical formula for the dispersion and attenuation constant of the dielectric filled hollow core leaky waveguide fiber are derived.The results of the analytical formula are completely consistent with the numerical results obtained by the full vector finite element method.The r elationship between the attenuation constant and the refractive index of the filling medium is explained by using the Fresnel equations.Thirdly,the transmission characteristics of liquid-filled hollow resonant fiber are studied by full vector finite element method.Two kinds of hollow core anti-resonant fibers with different parameters are fabricated by stack-and-draw method,and the transmission spectra of the hollow core anti-resonant fibers are measured when filled with air.The transmission spectrum and loss of the liquid-filled hollow core anti-resonant fiber are obtained by filling deionized water and anhydrous ethanol respectively.Finally,by establishing a mathematical model of the rate equation of liquid-core fiber laser,the effects of filling medium concentration,pump power and resonator mirror reflectivity on the output laser are optimized theoretically.In the experimental part,Rhodamine 6G dye solvent is injected into hollow core anti-resonant fiber and pumped by 532 nm pulsed laser.The laser output with low threshold and high slop efficiency in visible light band is obtained.