摘要
In order to study the beam cleanup effect of the stimulated Raman scattering （SRS） in the graded-index multi-mode fiber （GIMF）, a continuous wave all-fiber laser at 1117.8 nm and a pulsed fiber amplifier at 1064 nm are built up as the seed and pump source in the Raman fiber amplifier （RFA）. In unseeded SRS process, a pump beam with M^2x = 6.7 and M^2 = 6.7 is transferred into a Stokes beam with M^2x = 1.5 and M^2 = 1.7 in y y the multi-mode fiber with a 62.5 μm graded-index core （numerical aperture =0.29）. In the RFA, a seed light with M^2y = 6.7 and M^2y = 7.3 is amplified to a signal light with M^2x = 1.8 and M^2y = 2.0. The experimental y y results are explained by the simulation on the mode evolution during SRS procession and Raman amplification in the GIMF. The results show that both the SRS and Raman amplification effect in the GIMF have beam cleanup effect.
In order to study the beam cleanup effect of the stimulated Raman scattering （SRS） in the graded-index multi-mode fiber （GIMF）, a continuous wave all-fiber laser at 1117.8 nm and a pulsed fiber amplifier at 1064 nm are built up as the seed and pump source in the Raman fiber amplifier （RFA）. In unseeded SRS process, a pump beam with M^2x = 6.7 and M^2 = 6.7 is transferred into a Stokes beam with M^2x = 1.5 and M^2 = 1.7 in y y the multi-mode fiber with a 62.5 μm graded-index core （numerical aperture =0.29）. In the RFA, a seed light with M^2y = 6.7 and M^2y = 7.3 is amplified to a signal light with M^2x = 1.8 and M^2y = 2.0. The experimental y y results are explained by the simulation on the mode evolution during SRS procession and Raman amplification in the GIMF. The results show that both the SRS and Raman amplification effect in the GIMF have beam cleanup effect.
