Gain-flattened optical limiting amplifier modules for wavelength division multiplexing transmission

By integration of a bidirectional erbium-doped fiber amplifier and a three- port optical circulator with several fiber Bragg gratings (FBGs), two gain- flattened optical limiting amplifier (OLA) modules are proposed and experim entally demonstrated. They rely on the use of central wavelength misalignme nt and bending loss methods, respectively. They cart effectively cover the whole useful 1.55-mu m band. Both modules can provide gain-flattening chara cteristics over a large input dynamic range. The FBGs-integrated OLA config uration has potential application in wavelength division multiplexing light wave communication systems.