This lesson demonstrates generating the transients based on add-drops in signals in a Raman amplifier. In this example, we simulate a counter-pumped Raman amplifier for a small number of signals. They have relatively high optical powers of 8 kW and 200 W, respectively, which is realistic for nanosecond pulses, for example. The multimode fiber is assumed to have a parabolic refractive index. allenging problems for designing Raman ampli ̄ers or lasers is to develop a numerical method that meets all the requirements such as accuracy, robustn ty. The techniques applied in literature for solving propagation equations are mainly based on the ̄nite di®erences, shooting or in some cases. fier behaviors with diverse pump configurations. Incorporating frequency-dependent loss, Raman gain, and inter-signal Raman gain, it enables accurate evaluation of signal evolution and. Here, we simulate the propagation of an ultrashort pulse in a fiber amplifier, where the substantial fiber nonlinearity leads to stimulated Raman scattering (SRS). Note that for this purpose one could also use a nice Power Form, allowing users to get such results without any scripting on their. OptiAmplifier is an optical amplifier and laser design software, developed to address all aspects of EDFA/Raman amplifier engineering. The software applications include. used to predict Raman amplifier characteristics, and then, as an example of d utset, however, it will be more desirable, from the standpoint of decreasing initial invsetment, to effect bandwidth upgrading as the need arises.