The amplification effects on forward and backward stimulated Brillouin scattering (SBS) lines in the forward pumped S-band distributed G652 fiber Raman amplifier (FRA) have been studied. There is a pump threshold power of Stokes backward stimulated Brillouin scattering (B-SBS) line in the forward pumped G652 FRA, it is about 1 mW. The Stokes B-SBS lines are amplified by FRA and fiber Brillouin amplifier (FBA). The gain of amplification is given as Ga = GR GB where GR is Raman gain and GB is Brillouin gain. In experimental work, the saturation gain of the first order Stokes backward SBS line is about 58 dB and the saturation gain of 25-km G652 forward FRA is about 25 dB, so the gain of FBA is about 33 dB. The forward stimulated Brillouin scattering (F-SBS) is generated and amplified in S-band G652 FRA. The stimulated threshold powers of the forward first order Stokes SBS (SB-1), second order Stokes SBS (SB-2), and third order SBS (SB-3) in the forward pumped FRA are 2.3, 1.6, and 1.6 mW, respectively. In experimental work, the saturation gains of SB-1, SB-2, and SB-3 are about 38, 62, and 60 dB, respectively. The saturation Raman gain of 25-km G652 forward FRA is about 8.8 dB, so the Brillouin gains of SB-1, SB-2, and SB-3 are about 29.2, 53.2, and 51.2 dB, respectively. The forward and backward cascaded SBS lines have been observed.
© 2005 Chinese Optics LettersPDF Article