| Supercontinuum has the advantages of wide output spectrum,high brightness and good stability.In recent years,it has become a hot topic due to its potential applications in many fields such as spectroscopy,optical coherence tomography and optical measurement.In order to achieve spectral broadening and generate new frequency components,a material with high nonlinear,low linear and nonlinear losses is required.Tellurite glass has a wide infrared transmission window,high nonlinear coefficient and ultra-fast optical response time,and these excellent optical properties make it an ideal choice for middle infrared supercontinuum generation.In this paper,we designed and prepared tellurite glass by investigating the materials commonly used to produce supercontinuum,tested a series of tellurite materials,and completed the supercontinuum study of tellurite fiber.The specific work is as follows:1.Study the component design and preparation process of tellurite glass,prepare three components of tellurite glass materials,and test the performance indexes of the prepared samples.The transmission spectra of the tested samples were even,and the transmittance of the three samples exceeded 80%.There was no obvious oxide impurity absorption peak in the transmission spectra of the tested glass samples.The optical path of the prepared tellurite glass was used to construct the optical path for the ultra-continuous experiment,and the ultra-continuous broadening of the tellurite glass material was obtained.2.The third order nonlinearity of tellurite glass is studied.The basic theory of third-order nonlinear test was studied,and then the experimental device was set up for the third-order nonlinear test.The third-order nonlinear refractive index n2 of the tellurite glass sample was about5.9×10-19m2/W,and the nonlinear absorption coefficient=1×10-11m/W.The study of material nonlinear coefficient is a very important part in the supercontinuum experiment of glass materials,which will lay a solid foundation for the follow-up supercontinuum experiment.3.Supercontinuum spectrum simulation of tellurite glass fiber is carried out through COMSOL Multiphysics software.The mode field distribution diagram of single-mode fiber is obtained by waveguide design,and its influence on supercontinuum spectrum broadening is studied by changing certain parameters,such as the peak power and pulse width of pump light source,and the length of fiber,etc.The single mode fiber was made of tellurite glass,and the fiber with core diameter of 190μm-360μm was obtained. |
