Fan Xinyu, He Zuyuan, Hotate Kazuo
Opt Express. 2006 Jan 23;14(2):556-61. doi: 10.1364/opex.14.000556.
The first experimental observation of a dynamic grating in polarization-maintaining erbium-doped fiber (PM-EDF) is reported and a novel fiber-optic strain- and temperature-sensing mechanism based on the dynamic grating in PM-EDF is demonstrated experimentally. The dynamic grating is written with light beams in one primary polarization axis of the PM-EDF, and read with a light beam in the other primary polarization axis. The readout Bragg reflection wavelength of the grating differs from the writing wavelength and the wavelength difference is proportional to the birefringence between the two polarization axes. Making use of the dependence of the birefringence on strain or temperature, strain- and temperature-sensing is realized by measuring the Bragg reflection wavelength (frequency) shift. In order to detect the weak reflection from the dynamic grating, a dual-stage synchronous detection scheme is adopted in the experiment. The results show a strain-sensitivity of 1.4 MHz/microepsilon and a temperature-sensitivity of 60 MHz/ C, respectively.
报道了保偏掺铒光纤（PM-EDF）中动态光栅的首次实验观测，并通过实验证明了基于PM-EDF中动态光栅的新型光纤应变和温度传感机制。动态光栅由光束写入PM-EDF的一个主偏振轴，并由另一主偏振轴上的光束读取。光栅的读出布拉格反射波长与写入波长不同，且波长差与两个偏振轴之间的双折射成正比。利用双折射对应变或温度的依赖性，通过测量布拉格反射波长（频率）的偏移来实现应变和温度传感。为了检测来自动态光栅的微弱反射，实验中采用了双级同步检测方案。结果表明，应变灵敏度分别为1.4 MHz/με，温度灵敏度为60 MHz/℃。
