Simulation of a distributed fiber optic sensor as a delay line in an optoelectronic oscillator feedback loop

In various industries, it is crucial to monitor the longitudinal and transverse deformations and vibrations of distributed metal and reinforced concrete structures, as well as the movement of surrounding earth materials, in real-time to track their condition. Currently, optical control systems are commonly used for this purpose. However, there remains a significant need to develop new methods for polling distributed sensors to enhance the efficiency of these sensor systems. In this article, the authors describe an interrogator based on an integrated optoelectronic oscillator (OEO) designed to detect fiber deformations. The optical fiber serves as a sensitive element; any deformation results in a change in the signal frequency at the OEO's output. By analyzing the frequency value at the OEO's output, it is possible to determine the extent of the deformation and assess the external impact on the structure. To validate this concept, a numerical model of the interrogator was developed using Ansys Lumerical software. The simulation results confirm the proposed method's applicability and effectiveness in distributed monitoring systems.