Amplification effect on stimulated Brillouin scattering in the S-band forward G652 fiber Raman amplifier

摘要

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 G_a = G_R · G_B where G_R is Raman gain and G_B 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.