Research On Gain Flattening Of EDFA Based On VOA+GFF

Electroless relay transmission is under broad application in the national skeleton long-distance communication system. EDFA has become one of the key techniques in the long-distance optical communication. Along with the age of'light replacing cuprum'coming and continuous accretion of bandwidth requirement, DWDM has become the primary mode of long-distance transmission. This dissertation is focused on the characteristics of erbium-doped fiber amplifier (EDFA) used in dense wavelength division multiplexing (DWDM), which include:1. All kinds of the methods of gain flattening and the highest level achieved until now of EDFA in the world are expounded overall.2. The fundamental and the basic structure of EDFA system is studied in theory. The key concepts in EDFA system are expounded, including gain, noise figure and gain tilt. The relationships between gain/noise figure and EDF length/pump power, gain tilt and signal power/pump power of EDFA are numerically simulated.3. An EDFA of 980nm pumped, 2-stage cascade based, dynamic gain flattening based on VOA+GFF is designed, according to the design principle of EDFA.4. A gain flatness of±0.1dB within 30nm is achieved through the experiment based on LPG GFF when its output is 15.1dBm,through a mass of experiments. Dynamic gain flattening regulation is needed, because the gain flatness varies with diverse signal power.5. The regulation means of gain tilt based on VOA is put forward; and is proved to be effective. By the means of GFF + VOA, the gain flatness of EDFA system can be maintained at 0.1dB all along with diverse signal power.