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。

A full experimental characterization of mechanically induced long-period fiber gratings (MLPFGs) fabricated by pressing a plate with periodic grooves against a short length of fiber is presented. This technique enables a good control over the gratings’ isolation loss peaks and has high repeatability. The spectra characteristics of MLPFGs are studied with the change of the parameters including pressure, period, and temperature. The produced MLPFGs have low insertion loss (<0.2 dB) and the loss peaks can be higher than 20 dB. A large tunability of the resonant wavelength (>14 nm) is achieved through adjusting pressure grooves’ period. The center wavelength temperature sensitivities of 0.057, 0.086 nm/oC, and resonant peak temperature sensitivities of 0.230, 0.312 dB/oC, are achieved for jacketed and unjacketed fibers, respectively. These MLPFGs, which are simple and inexpensive, also offer the unique advantages of being tunable, erasable, and reconfigurable.