Optimization of the two-stage single-pump erbium-doped fiber amplifier with high amplification for low frequency nanoscale pulses

Abstract

We report the two-stage single-pump configuration of an erbium-doped fiber amplifier, in which a Sagnac interferometer is introduced to reduce the most important contribution of amplified spontaneous emission ͑ASE͒ noise, providing significant improvement on the amplifier performance. A Sagnac interferometer, made from a highbirefringence fiber loop, is included between the first and second stages. It is designed to provide transmittance with a period of 46 nm that allows us to adjust the minimum transmission around 1530 nm ͑peak of ASE noise͒ and maximum transmission at 1550 nm ͑signal wavelength͒. For optimizing the configuration, we measure the erbium-doped fiber parameters and simulate the amplification of the signal along the fiber. In the experiment, a significant absorption coefficient for pump and signal is found. The absorption looks to be too strong for the background absorption, and we suppose that it may be caused at least partly by excitedstate absorption ͑ESA͒. Including the absorption coefficient allows very good correspondence between simulation and experiment. Experimental results show that with a simple configuration, we obtain up to 53-dB amplification with only 73 mW of pump power.

Stimulated Raman Scattering for All Optical Switches

“…This diode laser is directly modulated by the pulse generator to generate pulses with duration of 2 ns. The pulses from the diode laser are amplified by an Erbium Doped Fiber Amplifier (EDFA) for power of several tens of Watts [21]. The pump pulses are introduced to the Coupler 1 (85/15), whose 85% port is spliced with the first stage comprising Fiber 1 + Fiber 2.…”

Neodymium, erbium, and ytterbium co-doped fiber amplifier

“…2,3 The ASE is emitted by the amplifier in both directions and at different wavelengths, and therefore reduces the amplifier gain. 4 The ASE at the signal wavelength degrades the system performance, since it increases the noise figure. 2 Another important issue in fiber amplifiers is Rayleigh backscattering (RBS), 5 which can interfere with the amplifier's performance.…”