Development of a cascaded Raman fiber laser with 6.5W output power at 1480nm supported by detailed numerical simulations

Wavelengths around 1480 nm can be used to pump Er-doped systems [1] in order to overcome small efficiencies and huge heat loads typically related with pumping wavelengths in the 976 nm region. Additionally, Er-doped fibers suffer from fundamental limits in doping concentration, so that pump sources with high brightness to enable core pumping are preferred over multimode (976nm or 1480nm) laser diodes. One possible way to reach the 1480nm region with single-mode beam quality is to use a cascaded Raman fiber laser, in which a 1117 nm pump wavelength is shifted in multiple steps towards 1480 nm via the Raman effect. Several experimental [2] and theoretical studies [3,4] on high power cascaded Raman fiber lasers have been reported. Nevertheless, it´s still a challenging process to develop such a system, especially, if no numerical simulation is available to support the optimization of the system. In this contribution, we report on the development of an all-fiber cascaded Raman laser supported by a detailed numerical analysis and on the comparison of simulated and measured results.