The device consists of an optical light source, a fiber optic structure Singlemode-Multimode-Singlemode (SMS) with a multimode 45 mm length, an audio generator, an output acoustical signal, an oscilloscope, and an optical power meter. Rayleigh scattering -based distributed acoustic sensing (DAS) systems use fiber optic cables to provide distributed strain sensing. In DAS, the optical fiber cable becomes the sensing element and measurements are made, and in part processed, using an attached optoelectronic device. Such a system. This paper gives a thorough look at how an intrinsic fiber optic acoustic sensor with a step index SMS structure works, what factors should be considered when designing it, how the experiments should be done, and how well it works. The sensor is specifically designed to accurately monitor both the. Radiation absorption excites an orbital electron to a higher energy level. It has many unique advantages, including, large coverage, high time-and-space resolution, convenient implementation, strong environment.
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