High-gain extended L-band EDFA with pre-amplified double-pass configuration

An extended L-band EDFA with a pre-amplified double-pass configuration is demonstrated. The main amplifier contains an Er/Yb/P co-doped fiber pumped by two 1480 nm laser diodes. And the pre-amplifier is formed by a conventional erbium-doped fiber pumped by a 980 nm laser diode. The 20- and 30-dB gain bandwidths reach 65 nm (1556-1621 nm) and 58 nm (1558-1616 nm), respectively, with a maximum gain of 48.8 dB at 1566 nm and a gain of 20.1 dB at 1621 nm. The noise figure is 5.61±1.75 dB in the range of 1565-1610 nm. Besides, the saturated output power is up to 20.58 dBm tested at 1605 nm.