Research On Ultrafast Soliton Fiber Laser Based On Carbon Nanotubes

Ultra-fast fiber lasers based on passive mode locking have advantages of simple structure,high stability and easy integration,it has been widely concerned by researchers.At the same time,mode-locked pulses under different dispersion conditions have their own excellent characteristics and important applications in optical fiber communication,industrial processing and ultra-fast precision detection.This paper mainly study the soliton pulse characteristics under the passive mode,through the dispersion management,the output of different dispersion domains are achieved,and based on the principle of self-similar amplification and chirp amplification,the wide spectrum of high power pulse can be realized,these have important research significance and application value in ultrashort pulse and high power fiber lasers.The specific research contents of this paper are as follows:1.In the fiber laser with carbon nanotubes saturable absorbers,the evolution of mode-locked pulses with intracavity dispersion is studied.Based on the dispersion management technology,the conventional soliton is realized in the negative dispersion domain.The spectrum has significant sideband characteristics and Sech2 distribution,and the pulse is stable and easy to obtain,which can be used as a good seed source.In the positive dispersion domain,the dissipative solitons is realized,the spectral shape is similar to rectangle,the pulse is Gaussian distribution,and it can withstand high nonlinearity without splitting.In the near zero dispersion domain,the dispersion management soliton is realized,the spectrum and pulse are Gaussian distribution.2.By adjusting the length of the single-mode fiber,the variation of the conventional soliton sideband with the negative dispersion is been studied.With the decrease of the length of single-mode fiber in the cavity,the number of traditional soliton sideband decreases gradually,the edge of the spectrum becomes smooth,the pulse energy and laser cavity stability are improved.3.Based on the principle of self-similar amplification,a ultrafast fiber laser with wide spectrum and high power output is constructed.The traditional soliton having smooth edge and no chirp can become the initial seed source,preliminarily evolving into parabolic pulse in dispersion optical fiber,with the increase of pump power,the gain of optical fiber spectrum,pulse width and power of monotone increasing,eventually we can obtain the output pulse with 37.4 nm spectral spectrum width and 164.5 mW power pulse.4.Based on the chirp amplification principle,a wide spectrum high power pulse output with spectrum width of 21.4nm and output power of 1.2W is realized.A dispersion management soliton with a certain chirp was selected as the seed source,and a high energy pulse output of 32.55nJ per single pulse was realized in the double-clad fiber through a certain degree of amplification.