Simulation And Experiment On Tm-doped Fiber Laser

The wavelength range of thulium doped silica fiber laser spreads from1.5to2.2μm, itcontains a strong absorption in water and biological tissues and two atmospheric window. Itcould effectively avoid the damage caused by the scattered light in minimally invasivesurgery. As the eye safe lasers and its high transmission in atmosphere, it can improve thetarget resolution8-10times respect to other LIDAR when it probe the ground.2micronthulium doped fiber laser are of interest for many application in the remote sensing,biomedicine, optoelectronic countermeasure and so on. Besides it can be used as the ideapump source for the3-5μm mid-infrared laser.The main content of this thesis contains:(1) Introduce the application of OSLO software on lens coupling system simulation,discuss the application of ABCD law in coupling the gauss beam into the fiber byaspheric lenses, get the lens focal length suitable for the Tm doped fiber with theconstrained optimization function(2) Analyze the relationship between phase mask period and the Bragg wavelength.Combined with the simulation on FBG reflectivity spectra, inscribing FBG on thedouble cladding Tm-doped fiber with the fs laser using phase mask method, theBragg wavelength lies at1971nm(3) With the simplified rate equation and boundary condition, modeling the Tm dopedfiber laser with MATLAB, simulate the distribution of laser and relative populationdensity during the Tm doped fiber with different ways of pumping.(4) Establish the space coupling fiber laser system, finally get the1971nm wavelengthlaser with10.7W output power. The M2factor was estimated to be1.58by theknife-edge method.