In this manuscript, an optically passive fiber Bragg grating (FBG) interrogation system able to perform high-frequency measurement is proposed. The idea is mainly based on the use of an arrayed waveguide grating (AWG) device which is used to discriminate the fiber optic sensor (FOS) wavelength encoded response under test in function of its output channels. As made clear by the theoretical model studied in the proposed manuscript, the Bragg wavelength shift can be detected as in linear dependence with the proposed interrogation function which changes with the voltage produced by two (or more) adjacent AWG output channels. To prove the feasibility of the system, some experimental analyses are conducted with a custom electrical module characterized by high-speed and low-noise operational amplifiers. As static measurements, three FBGs with different full width at half maximum (FWHM) have been monitored under wide-range wavelength variation; while, as dynamic measurement, one FBG, glued onto a metal plate, in order to sense the vibration at low and high frequency, was detected. The output signals have been processed by a digital acquisition (DAQ) board and a graphical user interface (GUI). The presented work highlights the characteristics of the proposed idea as competitor among the entire class of interrogation systems currently used. This is because here, the main device, that is the AWG, is passive and reliable, without the need to use modulation signals, or moving parts, that affect the speed of the system. In addition, the innovative multi-channel detection algorithm allows the use of any type of FOS without the need to have a perfectly match of spectra. Moreover, it is also characterized by a high dynamic range without loss of sensitivity.

中文翻译：

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基于阵列波导光栅的 FBG 询问系统的多通道方法

在这份手稿中，提出了一种能够执行高频测量的光学无源光纤布拉格光栅 (FBG) 询问系统。该想法主要基于阵列波导光栅 (AWG) 设备的使用，该设备用于根据其输出通道来区分被测光纤传感器 (FOS) 波长编码响应。正如在拟议手稿中研究的理论模型所表明的那样，可以检测到布拉格波长偏移与所提出的询问函数呈线性相关，该函数随两个（或更多）相邻 AWG 输出通道产生的电压而变化。为了证明该系统的可行性，使用具有高速和低噪声运算放大器特征的定制电气模块进行了一些实验分析。作为静态测量，在宽范围波长变化下监测了三个具有不同半高宽 (FWHM) 的 FBG；同时，作为动态测量，检测到一个 FBG 粘在金属板上，以检测低频和高频振动。输出信号已由数字采集 (DAQ) 板和图形用户界面 (GUI) 处理。所提出的工作突出了所提出的想法作为当前使用的整个审讯系统类别中的竞争者的特征。这是因为这里的主要设备，即 AWG，是无源且可靠的，无需使用影响系统速度的调制信号或移动部件。此外，创新的多通道检测算法允许使用任何类型的 FOS，而无需完美匹配光谱。