Li Shufeng, Yuan Pei, Li Ting, Li Bingxiang, Xu Ran, Yang Yiyao, Zhu Lianqing
Opt Lett. 2024 Feb 1;49(3):454-457. doi: 10.1364/OL.509893.
Compact fiber Bragg grating (FBG) interrogator is a widely investigated topic in the field of fiber optic sensing. Here we report a dense spectral arrayed waveguide grating (AWG) chip designed for FBG interrogation. By integrating a multimode interference (MMI) coupler with the AWG, bilateral input phase-differential optical signals were achieved at the input port of the AWG. This chip effectively doubles the output channel count without altering the device footprint, while concurrently reducing the channel spacing without modifying the bandwidth and spectral slope of the output spectrum. We further optimized the method for selecting interrogation channels. The results demonstrate that the dynamic range of the interrogation reaches 13.5 nm with an absolute wavelength resolution of 4 pm and an absolute accuracy better than 20 pm.
紧凑型光纤布拉格光栅（FBG）询问器是光纤传感领域中一个被广泛研究的课题。在此，我们报道一种为FBG询问而设计的密集光谱阵列波导光栅（AWG）芯片。通过将多模干涉（MMI）耦合器与AWG集成，在AWG的输入端口实现了双边输入相差光信号。该芯片在不改变器件占地面积的情况下有效地使输出通道数翻倍，同时在不改变输出光谱带宽和光谱斜率的情况下减小了通道间距。我们进一步优化了选择询问通道的方法。结果表明，询问的动态范围达到13.5 nm，绝对波长分辨率为4 pm，绝对精度优于20 pm。
