Studey On Er: Yb Codoped DFB Fiber Lasers

Compared with semiconductor lasers, distributed feedback fiber lasers have many advantages, just like compatibility with fiber, stability of output power, more purity optical spectrum, and lower relative noise intensity, and very narrow line width, more broader tunable range.The thesis simulated the reflection spectrum and delay spectrum of no-phase shifted DFB fiber lasers andπ/ 2 -phase shifted DFB fiber lasers. On the basis of phase shifted DFB fiber lasers, simulated some characteristic of parameters in Er³⁺ doped DFB fiber lasers, such as Er³⁺-ion inversion and output, and then studied the influence on output power when pump power and loss, length of fiber grating with different value, and preliminary research the optimum fiber length of fiber grating in making of Er³⁺ doped DFB fiber lasers. However, the value of Er³⁺-ion inversion in Er³⁺ doped DFB fiber lasers is not high, and that is seriously limited the output power of DFB fiber lasers.Considering the Er³⁺-ion inversion in Er³⁺ doped DFB fiber lasers is not high, the thesis take use the method of Er³⁺/Yb³⁺ co doped to improve the Er³⁺-ion inversion. Analyzed the energy exchange between Er³⁺-ion and Yb³⁺-ion,simulated some characteristic of parameters in Er³⁺/Yb³⁺ co doped F-P fiber lasers, like the distribution of forward and backward wave, the intensity of Er³⁺ -ion. Then introduced the F-P model to replace the T-matrix model to computing the Er³⁺-ion inversion in Er³⁺/Yb³⁺ co doped DFB fiber lasers, after that simulated some characteristic of parameters in Er³⁺/Yb³⁺ co doped DFB fiber lasers. At last the thesis compared the Er³⁺-ion inversion in Er³⁺/Yb³⁺ co doped DFB fiber lasers and it in Er³⁺ doped DFB fiber lasers, and then analyzed the influence of pump power, internal loss and length of fiber grating in Er³⁺/Yb³⁺ co doped DFB fiber lasers.The result indicated that F-P model could be used in DFB fiber lasers to computing the Er³⁺-ion inversion in Er³⁺/Yb³⁺ co doped DFB fiber lasers. The Er³⁺/Yb³⁺ co doped method could be made the value of Er³⁺-ion inversion higher, so the value of output power in Er³⁺/Yb³⁺ co doped DFB fiber lasers is improved.