The Study Of Multi-wavelength Fiber Laser Based On Fiber Taper And Stimulated Brillouin Scattering

The 2?m multi-wavelength fiber laser has attracted researchers' attention in recent years as it has great prospects of application in WDM systems,optical fiber sensing and other fields.But overall,the research on 2?m multi-wavelength fiber laser is still in its infancy,and needs researchers' further exploration.Based on the sinusoidal spectral response characteristics of taper fiber and the effect of stimulated brillouin scattering(SBS),this dissertation studies the 2?m multi-wavelength fiber laser,which can be divided into the following three parts.Part One: Numerical Investigation.Firstly,based on the nonlinear schrodinger equation,we establish the transmission model of light pulse in a single-mode optical fiber and thulium doped fiber gain.Then,according to the principles of saturable absorbe and the filtering mechanism of fiber taper,the corresponding theoretical models are established respectively.Finally,based on the mathematical model of fiber taper mode-lock fiber laser,the dual wavelength output is simulated respectively when the positive and negative net dispersion values of the laser.Part Two: Experiment on Multi-Wavelength Mode-locked Fiber Laser with Taper Fiber.Firstly,a linear cavity structure is established to verify the filter performance of fiber taper.The experimental results show that tapered fiber has a nearly sinusoidal spectral response curve with a period of 7.3nm.Besides,the experiment demonstrates that fiber taper is insensitive to the polarization state.Then,based on the filter property of fiber taper,the CNT mode-lock ring cavity structure is established.When the laser cavity has a negative net dispersion with adjustment of the pump power,we get the dual-wavelength output of CW/multi-soliton,soliton/multi-soliton and soliton/soliton.When we change the net dispersion value to positive by adding the DCF,in different pump power,we obtain the dual-wavelength output of CW/bound dissipative soliton,dissipative soliton/bound dissipative soliton,and dissipative soliton/dissipative soliton.In both cases,the wavelength interval is 22.4 nm.Besides,by stretching the fiber taper,we make the tuning of dual-wavelength reach 7.2 nm,which is the maximum value of tuning.Part Three: Experiment Based on Simulated Brillouin Scattering Multi-Wavelength Fiber Laser.Firstly,based on saturated absorption,we establish a ring cavity structure narrow linewidth fiber laser,and obtain the stable narrow linewidth single longitudinal laser.Then,we use the self-made narrow linewidth fiber as the brillouin pump sources,to establish the experiment system of stimulated brillouin scattering multi-wavelength fiber laser.By using the 700 m SMF-28 e,200 m SM2000 and 100 m UHNA7 as brillouin gain medium,we stimulate 3 order,4 order and 5 order stokes light respectively,whose corresponding wavelength intervals are 0.105 nm,0.11 nm and 0.09 nm.