Yuan Tingting, Zhong Xing, Guan Chunying, Fu Jianan, Yang Jing, Shi Jinhui, Yuan Libo
Opt Express. 2015 Dec 28;23(26):33378-85. doi: 10.1364/OE.23.033378.
Long period fiber gratings (LPGs) in a two-core hollow eccentric fiber (TCHF) have been demonstrated experimentally. Two LPGs have been fabricated into the respective core of the TCHF by a high frequency CO2 laser. The coupling characteristics in the TCHF-LPG have been studied using the coupling mode theory (CMT). The resonant peak is mainly caused by the coupling between the core mode LP01 and cladding mode LP81. The experimental results agree well with the simulation results. Furthermore, the sensing properties of the TCHF-LPG have been investigated with respect to bending, temperature and axial strain. Compared with the LPG in the single mode fiber (SMF), the experimental results indicate that the sensitivity of the TCHF-LPGs to bending curvature is low and even very small at some bending directions. In addition, TCHF-LPGs are insensitive to the axial strain while sensitive to the temperature. Therefore, the proposed TCHF-LPGs can efficiently sense the changing temperature that is independent of the strain. Moreover, the TCHF-LPGs can also be applied to two-channel filters without signal crosstalk between two cores.
已通过实验证明了两芯空心偏心光纤（TCHF）中的长周期光纤光栅（LPG）。利用高频CO2激光器在TCHF的各个芯中制作了两个LPG。使用耦合模理论（CMT）研究了TCHF-LPG中的耦合特性。谐振峰主要由芯模LP01与包层模LP81之间的耦合引起。实验结果与模拟结果吻合良好。此外，还研究了TCHF-LPG在弯曲、温度和轴向应变方面的传感特性。与单模光纤（SMF）中的LPG相比，实验结果表明，TCHF-LPG对弯曲曲率的灵敏度较低，在某些弯曲方向上甚至非常小。此外，TCHF-LPG对轴向应变不敏感，而对温度敏感。因此，所提出的TCHF-LPG能够有效地感测与应变无关的变化温度。此外，TCHF-LPG还可应用于两通道滤波器，且两芯之间无信号串扰。
