Xu Mingjing, Ma Lin, Yu Fengrui, Zhao Yunhe, He Zuyuan
Opt Lett. 2024 Oct 15;49(20):5953-5956. doi: 10.1364/OL.538595.
We demonstrate femtosecond laser direct writing long period gratings (LPGs) on multicore fibers (MCFs). By adopting the line-by-line inscription technique, LPGs can be independently fabricated at arbitrary cores of the MCF without removing the coating or altering fiber positions. Theoretical and experimental analyses were conducted to assess the laser energy distribution in the MCF and the impact of LPG parameters on filtering characteristics. LPGs inscribed in different cores under the same condition exhibited good spectral consistency, with a coupling efficiency of 90% (10 dB). Fabricated LPGs with various periods achieved multi-wavelength filtering effects in a single piece of the MCF with a widely adjustable wavelength range. The femtosecond laser direct inscription technique for fabricating spatial structures in the MCF demonstrates significant potential for space-division multiplexing (SDM) and wavelength-division multiplexing filtering applications.
我们展示了在多芯光纤（MCF）上用飞秒激光直接写入长周期光栅（LPG）。通过采用逐行写入技术，可以在MCF的任意纤芯上独立制作LPG，而无需去除涂层或改变光纤位置。进行了理论和实验分析，以评估MCF中的激光能量分布以及LPG参数对滤波特性的影响。在相同条件下写入不同纤芯的LPG表现出良好的光谱一致性，耦合效率为90%（10 dB）。制作的具有不同周期的LPG在单根MCF中实现了多波长滤波效果，波长范围可广泛调节。用于在MCF中制造空间结构的飞秒激光直接写入技术在空分复用（SDM）和波分复用滤波应用方面显示出巨大潜力。
