8 research outputs found
Transient gain dynamics in saturated counter-pumped raman amplifiers
No full textThe transient gain dynamics in saturated counter-pumped Raman amplifiers were analyzed. The strong power of the signal leading edge at the amplifier output was found to deplete the injected pump. It was shown that the gain dynamics were determined by the time behavior of a single state variable
Optimal placement of isolators in Raman amplified optical links
No full textExplicit formulae for the optimal placement of isolators inside distributed Raman
ampliers for the minimization of signal Double Rayleigh Backscattering are provided, and the
achievable improvement in optical signal to noise ratio is assessed
Transient gain dynamics in saturated Raman amplifiers
No full textThis paper provides a detailed analysis of transient gain dynamics in saturated Raman amplifiers
fed by wavelength division multiplexed (WDM) signals. Such dynamics are due to a pump saturation
effect, known as pump-mediated signal-to-signal crosstalk, which is equivalent to the well-known
cross-gain modulation in EDFAs. We provide for the first time a simple block-diagram model of the
Raman amplifier, whose state is represented by the relative pumps depletion sensed by the signals.
With such model, we are able to prove that the time constants of the Raman gain transients are of the
same order as the pump–signal walk-off times. For counter-propagating pumps, the model is very
accurate in predicting both the steady-state gain and the transient gain dynamics, with more than an
order of magnitude improvement in computation time with respect to the direct solution of the signals
and pumps propagation equations. The value of such model is therefore in the simulation of dynamic
WDM networking scenarios in which the input powers have large swings in time. The model also
extends to the co-propagating pump and well captures the time constants involved in the transients,
although the accuracy in the predicted power levels is worse than that of the counter-propagating
pump case
Impulsive pump depletion in saturated Raman amplifiers
No full textThe analytical results available for counter-propagating pump
distributed Raman amplifiers in the undepleted pump
approximation are shown to be easily extended to the signalsaturated
case by using effective values of both input pump and
sign a 1 s
