Yang Shuo, Hu Di, Wang Anbo
Opt Lett. 2017 Oct 15;42(20):4219-4222. doi: 10.1364/OL.42.004219.
The Letter reports the inscription of fiber Bragg gratings (FBGs) in a single-crystal sapphire optical fiber via a point-by-point method by 780 nm infrared-femtosecond laser pulses. Compared to phase mask exposure, the use of the point-by-point method for the inscription provides a flexible way to fabricate sapphire FBGs and to make wavelength division multiplexing in sapphire fiber more practicable. The multiplexing of three cascade gratings is demonstrated, and their performance up to 1400°C is tested. The permanent enhancement of reflectivity by a factor of about 5 after heat treatment and the nearly linear temperature response with a slope of 25.8 pm/°C are demonstrated.
该信函报道了通过逐点法利用780纳米红外飞秒激光脉冲在单晶蓝宝石光纤中写入光纤布拉格光栅（FBG）。与相位掩膜曝光相比，采用逐点法写入为制造蓝宝石FBG提供了一种灵活的方式，并使蓝宝石光纤中的波分复用更具实用性。文中展示了三个级联光栅的复用，并测试了它们在高达1400°C时的性能。结果表明，热处理后反射率永久性提高了约5倍，且温度响应近似线性，斜率为25.8皮米/°C。
