受激布里渊散射(SBS)的抑制是实现光纤参量放大的重要技术要求,已有文献报道多采用对抽运光进行相位调制的方法,将光功率分散到多个频率分量上来达到这一目的。提出一种二次调相的方法,在已有2 GHz相位调制的商品光源上施加365 MHz的二次相位调制,将高非线性光纤(HNLF)的受激布里渊散射阈值由未加任何调制时的10 dBm至少提高到23.5 dBm,达到了参量放大的要求。在此基础上,进行了连续波(CW)抽运的光纤参量放大实验。实验中采用长度为1450 m,非线性系数γ=11.9 W-1km-1,色散斜率S=0.0155 ps/(nm2?km)的高非线性光纤,使用外腔可调谐激光器(ECL)作为信号光源,小信号增益带宽达到26 nm(增益>10 dB),峰值增益达到24 dB。同时还观察到了由于非线性拉曼放大作用造成的长波长信号光增益大于短波长信号光增益的不对称性。

Suppression of the stimulated Brillouin scattering (SBS) is an important technology for realization of fiber parametric amplification. Phase modulation is employed in the early literatures to meet this purpose. A new method is proposed that a secondly phase modulation is applied on a modulated optical source. Based on this technique, by adding a 365 MHz phase modulation to the 2 GHz phase modulated laser source, the stimulated Brillouin scattering threshold is improved from 10 dBm to 23.5 dBm. Continuous wave (CW) pump optical parametric amplification is demonstrated experimentally in a 1450 m-long highly nonlinear fiber (HNLF), with the nonlinear coefficient γ=11.9 W-1km-1, dispersion slope S=0.0155 ps/(nm2?km). Using an external cavity laser (ECL) as the signal, 26 nm bandwidth (gain>10 dB) and 24 dB maximum gain for small signal are obtained.