机械感生长周期光纤光栅的实验

摘要

为了研究机械感生长周期光纤光栅 (MLPFGs) 的特性,利用机械微弯法写制了长周期光纤光栅.采用机械先加工技术制作了周期性压力槽,通过设计机械写制结构,制作了MLPFGs,并实验验证了周期性压力槽的周期、周期数以及外加应力等参数与MLPFGs透射谱的关系.最后, 研究了温度对带有涂敷层和无涂敷层单模光纤写制的MLPFGs的影响.实验表明:MLPFGs的最大谐振峰值可达16 dB,插入损耗＜0.5 dB; 通过改变压力槽的周期,实现了谐振波长＞14 nm的调谐范围;带有涂敷层和无涂敷层单模光纤写制的MLPFGs谐振波长的温度灵敏度分别为 0.057 nm/℃,0.086 nm/℃,谐振峰值的温度灵敏度分别为 0.230 dB/℃,0.312 dB/℃.该写制结构能较好地控制MLPFGs的透射谱,同时结构简单、易擦除、成本低,在光纤传感领域具有一定的应用价值.%With the aim to study the characteristics of Mechanically Induced Long-period Fiber Gratings (MLPFGs), the MLPFGs are fabricated based on the micro-curve principle. The grooved plates are made by the mechanical line processing technology and the MLPFGs are fabricated by pressing a plate with periodic grooves against a short length of fiber.Then, the relationship between MLPFG spectra and fabricated parameters, such as groove periods, period numbers, and pressures are studied. Finally, the influences of the temperature on the MLPFGs made from jacketed and unjacketed fibers are researched. Experimental results indicate that the produced MLPFGs have the insertion loss less than 0.5 dB and the loss peak as high as 16 dB. Moreover,a large tunability of the resonant wavelengths (>14 nm) has been achieved through adjusting the pressure grooves' period.The temperature sensitivities of the resonant loss peaks are 0.230 dB/℃ and 0.312 dB/℃, and the temperature sensitivities of the resonant wavelengths are 0.057 nm/℃ and 0.086 nm/℃ for jacketed and unjacketed fibers, respectively. These results show that this technique is able to control the grating isolation loss peaks and have a certain potential application value in the fiber sensing region for its characteristics by easy erasure and low costs.