Erbium doped fiber amplifier gain flattening using long-period fiber gratings

Based on theoretical and experimental studies on the optical properties of long-period gratings (LPGs), all erbium doped fiber amplifier (EDFA) gain e qualizer was fabricated by writing three long period gratings with designed properties in hydrogen-loaded standard single-mode fibers. The LPGs were w ritten by a. KrF excimer laser at 248 nm with amplitude masks. The gain var iation of +/-3 dB in the EDFA is reduced to +/-0.3 dB with a bandwidth of 3 0 nm and the total insertion loss of the device is less than 0.3 dB.