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), an erbium doped fiber amplifier (EDFA) gain equalizer was fabricated by writing three long period gratings with designed properties in hydrogen-loaded standard singlemode fibers. The LPGs were written by a KrF excimer laser at 248nm with amplitude masks. The gain variation of ±3dB in the EDFA is reduced to ±0.3dB with a bandwidth of 30nm and the total insertion loss of the device is less than 0.3dB.