Study On Tunable Erbium-doped Fiber Ring Laser

Tunable Erbium-Doped Fiber Laser (EDFL) has the characteristics of wide range, high coupling efficiency, low laser threshold, high signal-to-noise ratio. And it is widely applied to optical fiber communication, spectral analysis, laser medical system. So, the theoretical analysis and experimental study has very important practical value.In this paper, it describes the research purpose and significance of the paper at first. And it describes the history of the optical fiber laser and the developing trend. Then it introduces the energy level structure of erbium, and gains displacement and excited states absorption. And it makes the theoretical analysis, including the choice of pump, the choice of resonators. Through to the rate equations, the propagation equation and boundary conditions are discussed. We realize the ring cavity erbium laser output characteristics of the optical fiber, the optimization for theoretical basis.According to the analysis of the results, we choose to980nm pump source which is used to the system, to take the ring cavity erbium laser optical fiber experimental. We found that the structures and components of the ring cavity are very apparent for the influence of the wavelength range. And We researched the laser output characteristics under three different location of the isolation. Then it gained that the tuning ranges are112nm (1503～1615nm),117nm (1501～1618) and123nm (1498-1621nm). From the experiment data can be seen, the double isolation structure can get to maximize the tuning range.From the experimental results, the best erbium doped fiber length is about8m and the best output coupling ratio is about0.1. And the dependence of the output power and wavelength of EDFRL with pump power, EDF length and output coupling ratio is experimentally researched. Then Through the optical fiber laser are optimized, a new type of tunable Erbium-Doped Fiber Ring Laser (EDFRL) is implemented. Its operating wavelength can be continuously tuned over123nm (1498-1621nm). This is a great significance for the optimization and use of EDFRL.