A small signal average gain of 11.1 dB and the gain excursion low 1.0 dB was achieved with the forward pumping in the region from 1 560 to 1 610 nm.Taking into count the low gain,we utilize the way by inserting an auxiliary laser to enhance the small signal gain.With the same gain band and gain excursion,we achieved small signal average gain of 12.8 dB and 11.2 dB by inserting an -25 dBm signal in the wavelength of 1 532 nm and 1 551 nm,respectively.