Dual wavelength microwave frequency fiber interferometer system for distributed localization based on time delay estimation

Distributed optical fiber sensors have the advantages of corrosion resistance, anti-electromagnetic interference and adaptability to extreme environments. They can be used in perimeter security, pipeline monitoring, seismic detection and other fields. A novel optical fiber sensor called microwave frequency fiber interferometer has been proposed for low frequency sensing applications such as submarine seismic monitoring. However, the MFFI can only achieve integrated sensing and cannot achieve distributed localization of disturbances. In order to solve the problem that MFFI cannot achieve distributed localization and make it more suitable for long distance sensing applications, we propose a dual wavelength MFFI system based on wavelength division multiplexing to achieve distributed localization through time delay estimation algorithm. Our proposed system and algorithm make up for the inability of MFFI to achieve distributed localization and can be used in more sensing applications.