Zhang Zelin, Lu Yuangang, Pan Yuhang, Bao Xiaoyi, Chen Liang
Opt Express. 2019 Apr 15;27(8):11396-11405. doi: 10.1364/OE.27.011396.
The trench-assisted multimode fiber TA-OM4 is used as a sensing fiber to achieve a higher signal-to-noise (SNR) in Brillouin optical time domain sensors, due to its high stimulated Brillouin threshold and high modulation instability threshold. The Brillouin gain spectrum (BGS), stimulated Brillouin scattering (SBS) and modulation instability (MI) thresholds of TA-OM4 at 1550 nm are characterized and demonstrated theoretically and experimentally. The SNR improvements of TA-OM4 over G655 and G657 at the end of 15.5 km-long fibers, which are respectively 1.1 dB and 2.3 dB are verified experimentally. We achieve a temperature uncertainty of 0.3°C in 15.5 km TA-OM4 with 5 m spatial resolution by use of a Brillouin optical time domain reflectometry (BOTDR) sensor. The good bend resistance and high SBS and MI thresholds of TA-OM4 with better SNR improvements over SMFs works at the extreme bending conditions.
沟槽辅助多模光纤TA-OM4被用作传感光纤，以在布里渊光时域传感器中实现更高的信噪比（SNR），这归因于其较高的受激布里渊阈值和高调制不稳定性阈值。从理论和实验上对TA-OM4在1550 nm处的布里渊增益谱（BGS）、受激布里渊散射（SBS）和调制不稳定性（MI）阈值进行了表征和论证。实验验证了在15.5 km长光纤末端，TA-OM4相对于G655和G657的SNR改善分别为1.1 dB和2.3 dB。通过使用布里渊光时域反射仪（BOTDR）传感器，我们在15.5 km的TA-OM4中实现了0.3°C的温度不确定度，空间分辨率为5 m。TA-OM4具有良好的抗弯曲性、较高的SBS和MI阈值，相对于单模光纤具有更好的SNR改善，可在极端弯曲条件下工作。
