Research And Simulation Of Broadband Fiber Source

With the high-speed development of the optical communication and optical sensor,broadband high power optical source grows in importance.Broadband flatness optical source has important applications in optical communications.Besides,ultra-broadband optical source with stable center wavelength is important in fiber optic gyroscope.Due to the doped fiber optical source has a number of advantages,such as,stable emission spectrum,wider bandwidth,higher power,which caused extensive research.Doped fiber optical source has great potential to be applied in optoelectronics devices.Doped fiber source has been studied in detail in this paper.The luminescent properties of Re element and transitional metal has been studied in detail,based on this,we build a numerical model with energy level rate equations and power transfer equations for the Nd³⁺-Er³⁺-Tm³⁺co-doped,Bi³⁺-Bi²⁺-Bi⁺-Ti³⁺co-doped,Pr³⁺doped fiber source.We choose ASE as the research object,model is solved by MATLAB to examine the effect of the fiber parameters and pump power on the power of the ASE.This dissertation contains three main parts.The re-doped fiber source has been studied in detail in the first part.We selected the Nd³⁺,Er³⁺,Tm³⁺that emit in the near-infrared region covering the O,C,S band respectively.We use Nd³⁺-Er³⁺-Tm³⁺co-doped to achieve greater bandwidth covering multiple communications bands.We show the schematic energy level and absorption or emission cross section of each element,and build a numerical model for the Nd³⁺-Er³⁺-Tm³⁺co-doped fiber source considering energy transfer and cross-relaxation.Model is solved to analysis the factors affecting the power of the ASE.We mainly study the Bi and Ti in the second part.Under excitation of280nm and 800nm,the Bi(Bi³⁺,Bi²⁺,Bi⁺)has an ultra-broadband emission spectrum range from blue-green,orange,red,white to the near-infrared region which covers the spectral range of the traditional three primary colors?RGB?and also the telecommunications windows.Ti³⁺ion also has wide emission range in 0.6 to 0.9?m range.So,we can use Bi-Ti co-doped to achieve broadband fiber source.We show the schematic energy level.Emission and absorption spectrum are given to calculate the emission and absorption cross section using McCumber theory.Finally build a numerical model for the Bi³⁺-Bi²⁺-Bi⁺-Ti³⁺co-doped fiber source.Model is resolved to analysis the factors affecting the power of the ASE.Taking into account the complexity of element co-doped,we choose the Pr³⁺that has wide emission range in the near-infrared region in the third part.Through experiments we found that under excitation of 450nm,Pr³⁺has an ultra-broadband wavelength range from 1300nm to 1650nm covering the E,S,C and L telecommunications windows.We calculate the absorption of emission cross section based on the experimental data.Based on this,we build a numerical model for the Pr³⁺doped fibersource,and the newton iterative method is used to solve the rate equations,Runge-Kutta method is used to solve power transfer equations,afterwards we analysis the factors affecting the power of the ASE.