Hu Xuehao, Chen Yuhang, Gao Shixin, Min Rui, Woyessa Getinet, Bang Ole, Qu Hang, Wang Heng, Caucheteur Christophe
Research Center for Advanced Optics and Photoelectronics, Department of Physics, College of Science, Shantou University, Shantou 515063, China.
Key Laboratory of Intelligent Manufacturing Technology of MOE, Shantou University, Shantou 515063, China.
Polymers (Basel). 2022 Mar 26;14(7):1350. doi: 10.3390/polym14071350.
We experimentally report fiber Bragg gratings (FBGs) in a single mode step-index polymer optical fiber (POF) with a core made of TOPAS and cladding made of ZEONEX using 520 nm femtosecond pulses and a point-by-point (PbP) inscription method. With different pulse energies between 9.7 nJ and 11.2 nJ, 12 FBGs are distributed along the cores of two pieces of POFs with negative averaged effective index change up to ~6 × 10 in the TOPAS. For POF 1 with FBGs 1–6, the highest reflectivity 45.1% is obtained with a pulse energy of 10.6 nJ. After inscription, good grating stability is reported. Thanks to the post-annealing at 125 °C for 24 h, after cooling the grating reflectivity increases by ~10%. For POF 2 with FBGs 7–12, similar FBG data are obtained showing good reproducibility. Then, the FBGs are annealed at 125 °C for 78 h, and the average reflectivity of the FBGs during the annealing process increases by ~50% compared to that before the annealing, which could be potentially applied to humidity insensitive high temperature measurement.
我们通过实验报告了采用520纳米飞秒脉冲和逐点（PbP）写入方法，在一种单模阶跃折射率聚合物光纤（POF）中写入光纤布拉格光栅（FBG）的情况。该聚合物光纤的纤芯由TOPAS制成，包层由ZEONEX制成。在9.7纳焦至11.2纳焦之间的不同脉冲能量下，12个FBG分布在两根POF光纤的纤芯上，在TOPAS中平均有效折射率变化为负，高达约6×10。对于带有FBG 1 - 6的POF 1，在脉冲能量为10.6纳焦时获得了最高反射率45.1%。写入后，报告了良好的光栅稳定性。由于在125°C下进行24小时的后退火，冷却后光栅反射率提高了约10%。对于带有FBG 7 - 12的POF 2，获得了类似的FBG数据，显示出良好的可重复性。然后，将FBG在125°C下退火78小时，退火过程中FBG的平均反射率比退火前提高了约50%，这可能潜在地应用于对湿度不敏感的高温测量。
