Signal to Noise Ratio Enhancement in Multimode Fiber Based Phase Sensitive Optical Time Domain Reflectometry

Signal to noise ratio (SNR) plays a considerably important role in distributed acoustic sensing (DAS) applications. Gradually, single mode fiber (SMF) shows limitations gradually in SNR improvements. In this article, we propose a SNR enhancement phase-sensitive optical time domain reflectometry (Φ-OTDR) system for DAS. The main element is that multimode fiber (MMF) has been used as the fiber under test (FUT) instead of SMF. We demonstrate the advantages of MMF in SNR by comparing the above two fiber links launched into a Φ-OTDR system under various acoustic signal. The potential of MMF has been proved in this article.