Mompó Juan José, Urricelqui Javier, Loayssa Alayn
Opt Express. 2016 Jun 13;24(12):12672-81. doi: 10.1364/OE.24.012672.
We demonstrate a simple technique to provide conventional Brillouin optical time-domain analysis sensors with mitigation for pump pulse attenuation. The technique is based on operating the sensor in loss configuration so that energy is transferred from the probe wave to the pump pulse that becomes amplified as it counter-propagates with the probe wave. Furthermore, the optical frequency of the probe wave is modulated along the fiber so that the pump pulse experiences a flat total gain spectrum that equally amplifies all the spectral components of the pulse, hence, preventing distortion. This frequency modulation of the probe brings additional advantages because it provides increased tolerance to non-local effects and to spontaneous Brillouin scattering noise, so that a probe power above the Brillouin threshold of the fiber can be safely deployed, hence, increasing the signal-to-noise ratio of the measurement. The method is experimentally demonstrated in a 100-km fiber link, obtaining a measurement uncertainty of 1 MHz at the worst-contrast position.
我们展示了一种简单的技术，可为传统的布里渊光时域分析传感器提供泵浦脉冲衰减缓解措施。该技术基于在损耗配置下操作传感器，以便能量从探测波转移到泵浦脉冲，泵浦脉冲在与探测波反向传播时被放大。此外，探测波的光频率沿光纤进行调制，使得泵浦脉冲经历平坦的总增益谱，该增益谱能同等地放大脉冲的所有光谱成分，从而防止失真。探测波的这种频率调制带来了额外的优势，因为它提高了对非局部效应和自发布里渊散射噪声的耐受性，这样就可以安全地部署高于光纤布里渊阈值的探测功率，从而提高测量的信噪比。该方法在100公里的光纤链路中进行了实验验证，在对比度最差的位置获得了1兆赫兹的测量不确定度。
