Impact of amplified spontaneous emission noise on the SRS threshold of high-power fiber amplifiers

Abstract

Impact of amplified spontaneous emission (ASE) noise on the stimulated Raman scattering (SRS) threshold of high-power fiber amplifiers is demonstrated numerically through a spectral evolution approach. The simulation results confirm that ASE noise among the Raman wavelength band could reduce the SRS threshold of high-power fiber amplifiers significantly. As for ASE noise originated the main amplifier, it becomes stronger and reduces the SRS threshold at shorter operation wavelength below 1052 nm. As for ASE noise originated from the seed laser, it reduces the SRS threshold at different operation wavelength on the condition that the Raman ratio is over -90 dB in the seed laser. The theoretical method and results in this work could provide a well reference to extend the operation wavelength of high-power fiber lasers.

Experimental investigation of the stimulated Raman scattering effect in high-power nanosecond superfluorescent fiber source

“…The severe SPM results in a rapid spectral expansion on both wings of the central wavelength, even extending to the Raman wavelength band [ 34 ] . When the signal carrying the noise of the Raman wavelength band is amplified in the main amplifier, the SRS threshold will be reduced, leading to severe SRS [ 35 , 36 ] . It can be seen from Figure 4(a) that the wider the ns-SFS seed’s FWHM linewidth, the wider the spectral range of the amplified 18 W signals due to the SPM.…”

Design and optimization methods towards a 10 kW high beam quality fiber laser based on the counter tandem pumping scheme

“…To overcome SRS limitations, many effective approaches have been proposed [14][15][16][17][18][19][20] . For tandem-pumped YDFLs, one common and practical method is to enlarge the fiber core, as the Raman Stokes gain is inversely proportional to the fiber core area.…”