An inline time division multiplexed (TDM) fiber Bragg grating (FBG) interferometric sensor array for low frequency bands was presented. The length of the sensing fiber for each element was 58.78 m and the TDM number was 8, both of which are the largest to the best of our knowledge. Besides, in order to pick up phases stably in this ultra-long array with low background noise, a polarization switching (PS) and crosstalk suppressing method was adopted in which a hybrid interference complex synthesis and phase generated carrier (ICS-PGC) algorithm played an important role. A unified demonstration of the ICS-PGC method suitable for 8 or more TDM channels was presented. Experiments showed that even when the PGC modulation frequency was limited to be 6 kHz, the measured noise level could achieve −92 dB@100 Hz, making the system attractive for low frequency sensing applications.

提出了一种用于低频段的在线时分复用（TDM）光纤布拉格光栅（FBG）干涉传感器阵列。每个元素的传感光纤长度为58.78 m，TDM数量为8，这是我们所知最大的。此外，为了在背景噪声低的超长阵列中稳定地拾取相位，采用了极化切换（PS）和串扰抑制方法，其中采用了混合干扰复合和相位产生载波（ICS-PGC）算法。重要的角色。给出了适用于8个或更多TDM通道的ICS-PGC方法的统一演示。实验表明，即使将PGC调制频率限制为6 kHz，所测得的噪声水平也可以达到-92 dB @ 100 Hz，