Research On Design Of Organic Liquid-Core Photonic Crystal Fibers And Generation Of Supercontinuum

Supercontinuum(SC)has excellent characteristics,such as wide spectrum,high power density,and good coherence,and so on,and it has been widely used in communication,medical treatment,measurement,etc.With the development of scientific research,people have put forward more requirements on the performance of the SC.Photonic crystal fiber(PCF)is considered as an ideal medium for the SC generation because of its unique characteristics including endless single-mode transmission,enhanced mode field confinement,adjustable dispersion and nonlinearity,etc.In recent years,the liquid-core PCF has attracted great attention.Some organic liquids,such as nitrobenzene and toluene,have good transmission properties in the near-infrared region,and suitable linear refractive index and high nonlinear coefficient,so they are considered as the ideal liquids for filling the core of the PCF.This paper investigates and designs the organic liquid-core PCF,and demonstrates the generation and application of the SC by using the designed PCF.The main research works and achievements are summarized as follows:1.The transmission characteristic of the nitrobenzene-core PCF is investigated.The nitrobenzene-core PCF with an all-normal dispersion profile is designed.The simulation results show that the nonlinear coefficient of the designed PCF at wavelength 1560 nm is as high as 1.43 W-1 m-1,which is 100 times larger than that of the traditional silica PCF.2.The effect of the different fiber length on the SC under the all-normal dispersion is investigated.The research result indicates that the longer the fiber length,the wider the SC.The effects of the pump wavelength,pulse width,and peak power on the SC are also investigated.The simulation results show that the wider SC can be generated when the pump wavelength is longer,the pulse width is narrower,and the peak power is higher.Based on the above results,the highly coherent SC within the wavelength range of 1-2.3 ?m is obtained.And the effect of the noise on the SC is analyzed.Based on the generated SC,the octave-spanning and flat OFC is obtained.3.The transmission characteristic of the toluene core PCF is investigated.A toluene-core PCF with a near-zero flat dispersion profile is designed.The effect of the slow nonlinearity on the SC coherence is investigated when the PCF is pumped near the zero-dispersion wavelength in the anomalous dispersion region of the PCF.It is proved that the slow nonlinearity can improve the coherence of the SC through affecting the soliton splitting effect.4.The effect of the different fiber length on the SC under the anomalous dispersion is investigated.The research result indicates that the longer the fiber length,the wider the SC.The effects of the pump wavelength,pulse width,and peak power on the SC are also investigated.The simulation results show that the wider SC can be generated when the pump wavelength is longer,the pulse width is narrower,and the peak power is higher.Based on the above results,the highly coherent SC within the wavelength range of 1.1-2.1 ?m is obtained.And the effect of the noise on the SC is analyzed.Based on the generated SC,the octave-spanning and flat OFC is obtained.This paper simulates the generation and application of the SC by utilizing the high nonlinearity and slow nonlinearity of the organic liquids.The related results and achievements have enriched the research and generation technology of the SC.It can promote the research and application of the nonlinear optics to generate the highly coherent and octave-spanning SC.