Abrupt and asymptotic transience in DWDM systems using backward-pumped fiber Raman amplifier

Abrupt power transience in wide (C+L)-band dense wavelength division multiplexing systems caused by stimulated Raman scattering during channel add/drop is investigated both theoretically and experimentally. It is found that adding L- or C-band channels leads to abrupt decrease or increase in surviving C- or L-band channels and is constructively or destructively added to the asymptotic transience in a system using backward-pumped fiber Raman amplifiers. Dropping of L- or C-band channels also leads to reversed consequences. The impact of channel add/drop on the steady-state Raman gain in such systems is also investigated.