Study On Dissipative Soliton Fiber Laser

As one of the most important inventions of the twentieth Century, the laser technology is not only change people’s way of life,but also provide a powerful tool for the human exploration the essence characteristics of the material. So in the later forty or fifty years development, various types of lasers appeared, for example the solid-state laser, liquid laser, gas laser, semiconductor laser, dye laser, excimer laser and fiber laser etc. Among them, the fiber laser with its high conversion efficiency, compact structure, high beam quality, high stability, economical characteristics are favored by more and more scholars. However, in the history of the development of fiber laser, the traditional soliton generate in linear system, optical pulse is exist in the fiber core which has small mode field area, the high peak power density can be produced when small pump power input in laser, while the high peak power density will increase the nonlinear effect of the transfer process, the accumulation of excessive nonlinear phase shift can cause light wave breaking, so the traditional soliton energy is not too high. Dissipative soliton generate in nonlinear system, its production is mainly decided by the comprehensive effect of gain, loss, dispersion and nonlinear effect etc.The dissipative soliton formation is completely different from the conventional pulse, it can be generation without light wave breaking, and break limiting of energy of traditional soliton fiber laser.The main research contents in this paper are as follows:1.The theoretical research expounds the specific mechanism of dissipative soliton in characteristics of dissipative soliton in passively mode-locked fiber laser, At the same time, there is a more detailed description about effect of dispersion, nonlinearity effect and gain for the dissipative soliton. On this base, the Ginzburg-Landau equation which describe pulse transmission characteristics of lock mode fiber laser is introduced.2.Through experiment and numerical simulation achieve stable dissipative soliton output in dispersion-managed fiber laser which using carbon nanotubes as the saturable absorber. Common dissipative soliton spectrum shape is approximated as rectangular and having a sharp edge. Dissipative soliton pulse chirp is approximately linear in the experiment. In addition, theoretical analysis and numerical simulation the pulse characteristics, the generation mechanism and evolution law of this type of dissipative soliton. In the range of error, numerical simulation results agree with experimental results.3.Numerical simulation is used to research the dissipative soliton in dispersion-managed fiber laser, and study the evolution process of dissipative soliton with different net cavity dispersion. At the same time, changes of dissipative soliton characteristics are studied in the numerical simulation when changing the saturable absorber parameters. Finally, adding the bandpass filter in the system and changing the bandwidth of the bandpass filter to study its effect on the dissipative soliton characteristics.4.Numerical simulation is used to study the formation mechanism of the stable dark soliton and bright-dark soliton in all normal dispersion fiber laser. Finally, changes of dark soliton and bright-dark soliton characteristics are studied in the numerical simulation when changing the saturable absorber parameters and length of single mode fiber.