Study On Widely Tunable Erbium Doped Fiber Ring Laser

Tunable Erbium-Doped Fiber Laser(EDFL) is the key test device in the Optical Communication System(OCS) based on Dense Wavelength Division Multiplexing(DWDM). At the same time,it has been increasingly used in fiber optic sensor systems,gas detection systems,spectral analysis and other fields.Due to its potential application value,the EDFL has been developed rapidly and been one of the hottest topics in the fiber laser research fields.The main contents of the thesis include the numerical simulation and experimental studies on tunable EDFRL.The theoretical model of the EDFRL is established through the derivation and simplification of the rate equation and propagation equation of EDFRL pumped by a 980nm semiconductor laser.The shooting method and fourth order Runge-Kutta method are applied in numerical simulation of the EDFRL.By the numerical simulation,the factors of influence on the characteristics of the EDFRL are analyzed and studied in detail. And the results are used to guide the experimental studies on the EDFRL.After a brief historical overview and an introduction to the development status of EDFL technology,a theoretical background of the EDFRL is presented.Through building the model and numerical simulation,the influence factors on the characteristics of the EDFRL,such as the cavity loss,the length of EDF,the coupling ratio are studied.The experimental study on the EDFRL is also carried out and a comparison between the experimental research and numerical simulation is made.The results show that the theoretical simulation could accurately reflect the characteristics of the EDFRL.By optimizing the structure and parameter of the laser,a continuously tuning range over 135nm,the output power of 3mW with 3dB linewidth of 0.03nm and the optical signal to noise ratio of over 50dB are achieved.