Gain-enhanced double-pass long-wavelength-band erbium-doped fiber amplifier using backward pumping

Abstract

We propose and demonstrate a novel high-gain-efficiency long-wavelength band ͑L-band͒ erbium-doped fiber amplifier with a double-pass backward-pump configuration, in which the strong backward C-band amplified spontaneous emission is effectively utilized. The L-band gain is greatly enhanced in comparison with the copumped configuration. Without using any excessive components, the new configuration can provide the same gain as the conventional configuration, but only using 40% pump power. Meanwhile, the noise figure is also effectively improved under the low pump power.