Determination of homogeneous linewidth by spectral gainhole-burning in an erbium-doped fiber amplifier with GeO2:SiO2 core

Spectral gain hole-burning was observed at low temperatures in an erbium-doped fiber amplifier with GeO₂:SiO₂ core. At the peak wavelength λ=1.535 μm, homogeneous linewidths determined from the observed hole widths have a power-law dependence on temperature. At room temperature, the extrapolated homogeneous linewidth is 4 nm and the inhomogeneous linewidth is 8 nm     

Study of spectral dependence of gain saturation and effect ofinhomogeneous broadening in erbium-doped aluminosilicate fiberamplifiers

The special dependence of gain saturation and the effect of inhomogeneous broadening are investigated in erbium-doped aluminosilicate fiber amplifiers. Experimental data are compared with calculated results using two theoretical models, one assuming completely homogeneous saturation and the other including inhomogeneous gain broadening. Both the homogeneous model and the more accurate inhomogeneous model provide, without the use of fitting parameters, good agreement with experimental data     

Analysis of gain difference between forward- and backward-pumpederbium-doped fiber amplifiers in the saturation regime

In saturated erbium-doped fiber amplifiers (EDFAs), signal gain and power conversion efficiency are known to be greater in the backward pumping configuration. This study shows that the difference between pumping schemes is primarily an effect of amplified spontaneous emission. It is concluded that the highest conversion efficiency achievable in highly saturated EDFAs is predicted with fair accuracy by ASE noise-free models, but is approached most nearly with backward-pumped EDFAs     

Spectral noise figure of Er3+-doped fiber amplifiers

The erbium-doped fiber amplifier noise figure spectrum and its evolution under various pumping regimes is analyzed. The analysis shows that noise figures in the range ±0.15 dB around the 3-dB quantum limit are possible within a spectral band of 50 nm. This demonstrates the possibility of quantum-limited amplification for broadband wavelength-division multiplexed (WDM) signals     

Characterization and modeling of amplified spontaneous emission in unsaturated erbium-doped fiber amplifiers

The generation of amplified spontaneous emission (ASE) in erbium-doped fiber amplifiers (EDFAs) is characterized. A theoretical model, leading to closed-form analytical expressions for the backward and forward ASE power spectra, is developed for the unsaturated gain regime. This study shows that for the unsaturated gain regime, both power and spectral distributions of the ASE can be well described through the closed-form expressions, which require only measurable experimental parameters.<>     

High-gain optical amplification of laser diode signal by Raman scattering in single-mode fibres

The letter reports, for the first time, a 45 dB amplification gain of a laser diode signal emitting at 1.24 ?m, in a single-mode fibre, with low pump power, using the stimulated Raman scattering effect.     

Signal-to-noise ratio in Raman active fiber systems: Application to recirculating delay lines

An analysis of photon count statistics of noise in Raman fiber amplifiers and passive optical components is presented. The resuits are used for evaluating the output signal-to-noise ratio (SNR) of Raman active recirculating delay lines. It is found that the quadratic dependence of the noise on the number of recirculations causes the SNR to decay with increasing optical delays. Ultimate system performance capabilities, as determined by the SNR quantum limit, are discussed.     

Dynamic gain compensation in saturated erbium-doped fiber amplifiers

Dynamic compensation of low-frequency gain fluctuations in saturated erbium-doped fiber amplifiers is demonstrated. This compensation, based on a simple feedback-loop scheme makes it possible to reduce transient gain fluctuations efficiently across the whole amplifier bandwidth using only a low-power optical feedback signal. Such an, automatic gain control technique could be applied to suppress data packet interference due to traffic bursts in multiple-access networks, as well as in the implementation of long-haul fiber systems using erbium fiber amplifiers.<>     

An Explicit Analytical Solution for the Transcendental Equation Describing Saturated Erbium-Doped Fiber Amplifiers

Analytical modeling of erbium-doped fiber amplifiers (EDFA) in all operating regimes (i.e., small-signal, signal-saturated, self-saturated, uni- or bidirectionally pumped) requires solving a transcendental equation derived by Saleh et al. in 1990. In this paper, we describe an approximate, although accurate, explicit analytical solution for such a transcendental equation. The use of this explicit solution alleviates computational time constraints and should therefore permit extensive multidimensional or parametric studies of EDFAs. It could be advantageously applied to the study of multiwavelength amplified network systems, with new potentials for interactive computer-assisted design.