Gain-Clamped 4-LP-Mode Erbium-Doped Fiber Amplifier With Low Temporal Gain Variation.

We demonstrate a ring-resonator-based gain-clam ped 4-LP-mode erbium-doped fiber amplifier (EDFA). In this study, we show that a gain-clamped EDFA can reduce temporal modal gain variation simultaneously in all modes. We experimentally evaluate the transient response of a 4-LP-mode EDFA and succeed in reducing the modal gain variation for all modes at 1530 and 1550 nm from 4.0 to 1.1 dB and from 2.8 to 0.7 dB, respectively, by using a gain-clamping technique. [ABSTRACT FROM AUTHOR]