Opt Lett. 2019 Nov 1;44(21):5202-5205. doi: 10.1364/OL.44.005202.
An interrogation technique for large-capacity densely spaced fiber Bragg grating (FBG) arrays is demonstrated using incoherent optical frequency domain reflectometry (I-OFDR). A distributed-feedback laser diode under chaotic oscillation, modulated by a frequency-swept microwave, is adopted as the optical source. The reflected sensing signals are converted into electrical signals and subsequently mixed with the original microwave. Fast Fourier transform is applied to the generated beat signal to obtain the position of individual FBGs, while thermal tuning of the lasing wavelength leads to the demodulation of wavelength. By using the chaotic source, interference among the reflected sensing signals is reduced, leading to a significantly improved spatial resolution of 10 cm, with a multiplexing capacity of 3640 and wavelength demodulation accuracy of 15 pm.
利用非相干光频域反射计（I-OFDR）演示了一种用于大容量密集光纤布拉格光栅（FBG）阵列的检测技术。采用混沌振荡的分布反馈激光二极管，由扫频微波进行调制作为光源。反射传感信号被转换为电信号，并与原始微波进行混频。对产生的拍频信号进行快速傅里叶变换，以获得各个 FBG 的位置，而激光波长的热调谐则实现了波长的解调。通过使用混沌源，减少了反射传感信号之间的干扰，从而显著提高了空间分辨率，达到 10 cm，复用容量为 3640，波长解调精度为 15 pm。
