DBR光纤激光器拍频传感及其组网技术研究

研究了基于单纵模分布Bragg反射(DBR)光纤激光器的拍频解调传感技术,并对其组网技术进行了探讨。由于光纤本身的固有双折射,DBR光纤激光器能够产生两种正交偏振模式的激光,而这两种偏振模式的频率差拍会在射频域形成对温度变化极为敏感的拍频(beatfrequency)。实验结果表明:在20～100℃的温度范围内,激光器拍频随温度的增加呈线性减小,其线性拟合度高达0.99981,拍频灵敏度为0.51063MHz/℃。这种偏振式光纤激光器具有高输出功率、高信噪比、低解调成本和窄输出线宽等特点,有助于构建大规模的光纤有源传感网络。参考近年关于光纤传感网络的报道,提出一种有源光纤环形传感网络的构想。

Investigation of DBR fiber laser sensing based on beat frequency interrogation and its networking technique

In this paper,a single-longitudinal-mode distributed Bragg reflector(DBR) fiber laser based on beat frequency interrogation is presented and its networking technique is also discussed.Due to the inherent fiber birefringence, the output laser consists of two orthogonal polarization modes highly sensitive to the change of temperature.Experimental results indicate that the beat frequency linearly decreases with the increase of temperature from 20 ℃ to 100 ℃, and the linearity is 0.999 81.Besides,its sensitivity reaches 0.510 63 MHz/℃.The proposed polarimetric fiber laser possesses several advantages,such as high output power,high signal-to-noise ratio, low cost and narrow laser line width, all of which are good for the construction of large-scale fiber sensing networks.Based on recent reports on fiber sensor networks, an active fiber ring sensing network is proposed, and the future work is the realization of this network scheme.