【摘要】：The average power of fiber lasers has been scaled deeply into the kW regime in the past years. However, stimulated Raman scattering(SRS) is still a major factor limiting further power scaling. Here, we have demonstrated for the first time, to the best of our knowledge, the suppression of SRS in a half 10 kW tandem pumping fiber amplifier using chirped and tilted fiber Bragg gratings(CTFBGs). With specially self-designed and manufactured CTFBGs inserted between the seed laser and the amplifier stage, a maximum SRS suppression ratio of 15 dB in spectrum is observed with no reduction in laser efficiency. With one CTFBG, the effective output power is improved to3.9 kW with a beam quality M2 factor of ～1.7 from 3.5 k W with an M2 factor of 2; with two CTFBGs, the effective laser power reaches 4.2 kW with an increasing ratio of 20% and an M2 factor of ～1.8, and further power improvement is limited by the power and performance of the 1018 nm pump sources. This work provides an effective SRS suppression method for high-power all-fiber lasers, which is useful for further power scaling of these systems.
F.Miyahara;H.Fukasawa;R.Hashimoto;T.Ishikawa;M.Itoh;T.Iwata;H.Kanda;J.Kasagi;H.Kato;T.Kinoshita;K.Maeda;M.Matsuzawa;T.Michigami;K.Motiduki;K.Murakami;T.Nakabayashi;K.Nawa;T.Nomura;K.Okamura;H.Okamura;H.Okuyama;Y.Onodera;Y.Saito;T.Sasaki;H.Shimizu;T.Shishido;S.Suzuki;K.Suzuki;Y.Tajima;S.Takita;T.Takahashi;H.Ueno;S.Yamaguchi;H.Yamazaki;H.Y.Yoshida;;π~0 Photoproduction on Deuteron for Photon Energies from 0.6 to 1.15 GeV[J];原子核物理评论;2009年S1期