Theoretical And Experimental Study On ASE Light Source, EDFA And Fiber Laser

The rapid development of optical communication, the mature of technology of manufacturing fiber optic and semiconductor lasers provided the foundation of the development of fiber lasers and EDFAs (Erbium-Doped Fiber Amplifiers). As the emission spectrum of Erbium ions covers 1550nm, which is the low loss window in fiber optic communication, the study on EDFA and fiber laser is crucial for the development of technology of fiber optical communication.In this paper, the theoretical and experimental study on EDFA, ASE (Amplified spontaneous emission) light source and Erbium-doped fiber ring laser are made. At the beginning of this paper, the fundamental principle, structure, the property of gain and noise of EDFA are introduced. And the numerical simulation in theory is made, according to the parameters of Erbium-doped fiber and laser diode at wavelength 980nm used in the experiment. The factors affecting the gain of EDFA are analyzed so that the optimized design is realized. Then the EDFA designed is tested. Through the experiment, an EDFA of gain 35dB is obtained. The result deviates a little from the theoretical one. And the reasons caused the deviation are discussed in detail. Due to the existence of ASE effect, there is noise in EDFA, that is to say even there is no input signal, we can get an output spectrum at theterminal. Based on this principle, the spectra of ASE covering conventional band and Long band are tested. So that we obtain an ASE light source of output power 0.8228mW when it is pumped by 30 mW , and the width of spectrum is 43nm, the ripple is 0.08dB. In the following, the theoretical simulation on the Erbium-doped fiber ring laser is carried out. According to the results, the optimized design of it is realized. Then the property of the laser is tested. It emits 0.3798mW power when pumped by 32.04mW and the center wavelength is 1547nm, the width of the spectrum is 0.8nm and its efficiency is 3.87% ,which is accord with the theoretical result. During the experiment, some interesting phenomenon are found, then a brief discussion and some assumption for the further study are made.