论文部分内容阅读
理论分析和模拟计算了少模光纤布拉格光栅基模及高阶模的耦合与传输特性,得到在相同外部折射率变化情况下,少模光纤基模与高阶模耦合对应的布拉格波长变化,比正、反向基模之间耦合对应的布拉格波长变化显著增大。实验上制作了少模光纤布拉格光栅,测量了基模之间以及基模与高阶模之间对应的布拉格波长随外部折射率、温度变化的情况,得到与理论分析相符的结果。而对于温度变化对折射率测量结果干扰的问题,提出了通过计算布拉格波长差来克服温度影响的方法。这些结果为采用布拉格光纤光栅测量外部折射率变化提供了一种新的途径。
Theoretical analysis and simulation of the coupling and transmission characteristics of the fundamental mode and the higher-order mode of the mode-less fiber Bragg grating are given. The change of the Bragg wavelength corresponding to the coupling of the fundamental mode and the higher-order mode of the mode-less fiber is obtained under the same external refractive index change, The Bragg wavelength changes corresponding to the coupling between the fundamental modes are significantly increased. Experimentally, a small mode fiber Bragg grating was fabricated. The corresponding Bragg wavelength of the fundamental mode and the fundamental mode and the higher mode mode were measured with the change of external refractive index and temperature. The results were in good agreement with the theoretical analysis. However, for the problem that the temperature changes the measurement result of the refractive index, a method of overcoming the influence of temperature by calculating the wavelength difference of Bragg’s is proposed. These results provide a new way to measure the change of external refractive index with Bragg fiber grating.