基于超磁致伸缩材料的光纤光栅调谐范围研究

研究了基于超磁致伸缩材料实现对光纤布拉格光栅的动态调谐这一方案理论上可获得的最大调谐范围．利用超磁致伸缩换能器的输出特性，进行了超磁致伸缩换能器用于光纤布拉格光栅调谐的实验研究．分析了实验中影响可获得调谐范围的各种因素，如实际可获得的超磁致伸缩材料的特性、光纤布拉格光栅的特性以及换能器结构的设计．进一步讨论了在理论界限的前提下改进该方案可获得调谐范围的措施，并以施加预应力为例进行了实验验证．结果表明，通过给予超磁致伸缩材料合适的预应力，可以较明显地改善最大调谐范围．

On Tunable Range of Giant Magnetostrictive Based Fiber Bragg Grating Tuning

The achievable tuning range of the giant magnetostrictive based fiber Bragg grating tuning scheme is studied.Employing a giant magnetostrictive rod as the electrical-mechanical energy transducer,the analysis is further validated with experimental results.While a maximum tuning range on the order of 2.2 nm is viable theoretically,far smaller tuning range may result experimentally.Factors that may have affected the achievable tuning range negatively are pointed out,such as the magnetostrictive properties of the transducer,the properties of the fiber Bragg grating,the design of the magnetostrictive transducer,etc.Some possibilities to improve the tuning range experimentally are discussed and experimented.Results show that while the magnetostrictive property of the transducer is the most important factor that limits the achievable tuning range fundamentally,further improvement is possible through the application of appropriate prestrain to the magnetostrictive transducer.