Impact of nonlinear pump interactions on broadband distributed Raman amplification

A perturbation method for analysis of TDM-pumped fiber Raman amplifier

“…The above relations prove that reducing the interaction time of signal and pumps will reduce the corresponding effective Raman gain coefficient. Solutions of the partial differential equations (8) and (9) are written in the following form: …”

“…This results in almost linear wavelength variation of the optical signal to noise ratio, with a weak OSNR for short wavelength channels [10]. Furthermore, in fibers with a zero-dispersion wavelength close to long wavelength pumps, four wave-mixing (FWM) between pumps can produce some strong unwanted frequencies in the signal band [9,10]. In order to overcome the above-mentioned deficiencies of the conventional multi-wavelength pumped wide-band FRAs, time division multiplexed (TDM) pumping has been suggested and verified theoretically and experimentally [11][12][13][14][15][16][17][18][19].…”

Survey of systems experiments demonstrating dispersion compensation technologies

“…4(a). The "mediumdispersion" fiber types have an advantage for Raman amplification over earlier generations of NZDSF fiber in that the dispersion zero is at a shorter wavelength outside the 1400-1480 nm range of the required Raman pump lasers for C-and L-band operation so that there is less pump-to-pump [27] and pump-to-signal [2.24] four-wave mixing. Figure 4(b) shows the gain distribution across the L-band from the co-and counter-propagating span amplification and from the DCF amplification, and the total gain.…”

Transmission of 20 × 10 GE channels over 334 km in a cascade of three TDM-pumped RFAs

“…Pump-to-pump interactions are also reflected in the necessity for higher pump power of short wavelength pump sources compared to the longer wavelength ones. Moreover, strong products of four-wave mixing between the pumps can fall in the signal band when dispersion shifted fibre (DSF) is used as transmission medium [11].…”